Rehabilitation strategies for leprosy should contain physical virus 43215 order generic nitrofurantoin canada, psychological antibiotic resistant gram positive bacteria buy discount nitrofurantoin 50mg on line, social antibiotic eye drops for stye generic nitrofurantoin 50 mg with amex, and economic aspects antimicrobial humidifiers discount nitrofurantoin 50 mg with visa. Up to now virus model 50mg nitrofurantoin with amex, most leprosy control programs have been focused on physical rehabilitation only right antibiotic for sinus infection cheap 100 mg nitrofurantoin visa. These are specifically adapted for the local needs and differ among countries and from area to area antibiotic kinds purchase cheap nitrofurantoin online. In 1997 two million people worldwide were the body and how does it spread a) within the infected with M infection heart purchase nitrofurantoin canada. What is the host response to the infection and organisms, 1?8 mm long and approximately what is the disease pathogenesis? These antibodies in combination with nonappreciable lost genes coding for the metabolic pathways cellular immune response result in widespread have been replaced in M. The borderline forms of leprosy are characterized aerosol spread or exposure to nasal and oral mucosa. How is the disease diagnosed and what is the combination of dapsone 100 mg and clofazimine differential diagnosis? Classification of leprosy according to Comparative genomics of the leprosy and tubercle bacilli. Immunol Cell Biol, Mycobacterium leprae to endothelial cells of epineurial and per 2000, 78: 318?324. Lepr Rev, 1995, genes related to drug resistance in Mycobacterium leprae isolates 66: 134?143. Which of the following laboratory tests are used for the establishment or confirmation of the diagnosis of C. Case 23 Mycobacterium tuberculosis A 63-year-old man lived in a hostel for the homeless and sold magazines outside a railway station. He had been finding it difficult to cope with this recently, as he had been feeling weak, had lost weight, and often had a fever at night. One month ago, he started coughing up blood and feeling breathless, which had really worried him. He was not registered with a primary health-care provider but a friend told him about a walk-in practice for homeless people. Next day he went to the practice and was seen by the physician on duty, who found that the patient had a low-grade fever and detected bronchial breathing when he listened to his chest. There is also some taken since the doctor suspected that the patient had consolidation adjacent to the mediastinum on the right. It is a weakly gram positive mycobacterium classified as an acid-fast bacillus? because the dye that is used to stain it is resistant to removal by acid. Overlying this is a layer of arabinogalactan, which is covalently linked to Figure 2. Ziehl-Neelsen stain of the outer layer composed of mycolic acid, long chain fatty acids specific for sputum: note the red bacilli the mycobacterial genus, with other components such as glycophospho (arrowed) against a green lipids and trehalose dimycolate (also called cord factor as on staining the background stain. Running vertically through the only genus of medically important whole of the cell wall and linked to the cytoplasmic membrane is lipoara bacteria that stains red with the Ziehl binomannan (Figure 3). The mycolic acid layer is impervious to many substances necessitating the presence of porin mycolic acid channels to allow entry of hydophilic compounds. Mycobacterium leprae, the causative agent of leprosy and a close relative of the tubercle bacillus, cannot be grown on artificial media and can only be propagated in armadillos. This means that clinical decisions affecting treatment of tuberculosis and leprosy and the diagnosis of these conditions do not rely primarily on culture. The slow growth also raises problems in determining the actual species causing illness (as the treatment may vary depending on the causative agent) and in determining antibiotic resistance. The usual medium for the isolation and growth of mycobacteria is Lowenstein-Jensen, which con tains egg yolk and a dye (malachite green) that inhibits the growth of more rapidly growing bacteria (Figure 4). Entry into the alve olar macrophages is mediated through a variety of surface receptors expressed by these phagocytic cells. These include surface complement receptors, scavenger receptors, and Fc-g receptors. Growth of Mycobacterium receptors also recognize mycobacterial compounds but are not involved in tuberculosis. Although the organism can multiply extracellularly to some does not produce a pigment (A) but the extent within the alveolus, the organism is able to survive and multiply growth of another mycobacterial species within the macrophages (due to mechanisms that prevent killing within produce a yellow pigment (B). Eventually macrophages die by programmed cell death (apoptosis) and release mycobacteria. Dendritic cells also take up mycobacteria and become activated, which induces their migration to draining lymph nodes where they prime/activate T cells. The site of infection in the lungs tends to be at the base and close to the pleura. After up to 3 weeks and usually before cell-mediated immunity develops to any great extent, the microorganisms are released from the macrophages and spread via the bloodstream to draining regional lymph nodes, for example hilar or mediastinal, as well as to every organ in the body (principally the lung apices, meninges, kidneys, and bones). Macrophages can also carry viable microorganisms around the body and how much of the spread is via this mechanism is unclear. Thus most indi viduals are able to control the initial infection, showing either no symp toms or mild clinical manifestations similar to those seen for a common cold. However, most infected individuals carry the organism in a latent state for life under the control of an effective immune system (see below). Some may develop active disease many years after primary infection, often when they become immunosuppressed (reactivation). The aerosols produced contain droplet nuclei and survive for quite long periods of time outside the body. It is estimated that each infected person infects on average 20 other individuals. Repeated contact with an infected individual, particu larly in a closed environment, produces higher transmission rates than casual contact. The number of times an index case coughs is also directly related to the transmission rate. It is estimated that someone is newly infected every second and that the mortality from tuberculosis could be as high as 4 million per annum in 2020. In an infectious process, normally bacteria that are taken up by macrophages are killed within the phagolysosome. However, mycobacteria can live and divide within the macrophages by inhibiting maturation of their phago somes to prevent fusion with lysosomes and phagolysosome formation (through some of their cell wall glycolipids such as the cord factor or tre halose dimycolate) and are thus not exposed to the bactericidal content of the lysosome. The host may also respond by inducing a mechanism called autophagy,? which is not only the recycling system of the host cell but also a mechanism to target intracellular microorganisms to lysosomes. Although difficult to prove, in some primary infected individuals the organ ism is likely to be completely eliminated from the body. Not being able to eliminate the organism com killing mechanisms in the macrophages so pletely results in the production of a connective tissue layer to wall off? the that some mycobacteria can be killed. This is the containment phase (latent Modified from Lydyard, Whelan and Fanger infection with dormant mycobacteria) of the disease. Post infection, 3?5% of individuals get active disease within the first year but this might rise to 15?35% in subsequent years depending on several conditions, especially immunosuppression (e. Whether or not someone gets active or quiescent disease depends upon the following factors. Histologically, a granuloma is a collection of activated macrophages called epithelioid cells and a center that frequently shows an area of tissue necro sis. In tuberculosis, the necrosis is characteristically cheesy? and is called caseous necrosis. This is a classic form of chronic inflammation through persist ence of the infectious agent. In this form there is an equilibrium set up granuloma formation between the immune system and the organism that keeps live organisms in check. Some of the granulomas multinucleated giant cell cavitate (decay into a structureless mass of cellular debris), rupture, and spill epithelioid cell thousands of viable, infectious bacilli into the airways (if they are in the lung). T cells Reactivation can also take place within granulomas at other sites in the body leading to active disease, for example in the brain causing meningitis. Strong T-cell immunity and high dosage: there is greater tissue damage and caseation. What is the typical clinical presentation and what epithelioid cells, and multinucleate complications can occur? The most common clinical presentation is of a temperature, chronic pro ductive cough that may be streaked with blood (hemoptysis), and weight loss. Adjacent granulomas in lymph nodes may fuse to produce a sizeable lump, which can be seen in a chest X-ray in the medi astinum or tissue destruction and cavities produced by dead tissue (cavita tion, see Figure 1). The tissue destruction in the lungs resulting in cavita tion can lead to loss of lung volume and erosion of bronchial arteries (cav itation, see Figure 1). Spread of the organism through the body can lead to granulomas developing in other organs such as brain, bone, liver, and so forth; perhaps the most common complication being the space-occupying? effects of granulomas, for exam ple in the brain, where it can lead to seizures. Tuberculosis can thus pres ent with protean manifestations such as adrenal failure (Addisons disease) and fractures if it occurs in bone, for example vertebral collapse (Potts dis ease) (see Further Reading: Lydyard et al, 2000). The infection then moves to including T cells the lung parenchyma where monocytes and T cells are recruited through cytokines produced by the infected macrophages. The organism grows slowly within the 2 active lung disease 3 immunity resident and moncyte derived 5% of individuals immune system eliminates macrophages and the organisms M. The patient develops symptoms at 95% of individuals this stage and can infect other people. How is this disease diagnosed and what is the differential co-infection), reactivation of the growth of diagnosis? This results in further spread and treatment of tuberculosis and the diagnosis of this condition do not rely growth of the organism. However, culture remains the gold standard for con other than the lung, for example the brain firming diagnosis of tuberculosis. If reactivation determining the actual species causing illness (as the treatment may vary occurs in the lung, the individual becomes depending on the causative agent) and in determining the strain of infectious. Therefore diagnosis is principally a clinical decision and treatment is started on that basis. More rapid growth and detection can be achieved in automated machines by detecting metabolic products of radioactively labeled substrates, but this can still take 7?14 days. Differential diagnosis For the differential diagnosis, it is important that the typical symptoms of weight loss, chronic cough, and fever may also be present with tumors of the lung, for example adenocarcinoma, squamous cell carcinoma, oat cell carcinoma. The antigen(s) is unknown in some cases of granulomatous disease, for example sarcoidosis. Management Infected patients in hospital should be isolated in a negative pressure room (where the air pressure outside the room is greater than that in the room thus any airflow is into the room). Health-care workers should wear close-fitting masks if they are involved in activities likely to induce coughing/expectora tion by the patient, for example physiotherapists. Once the patient has been on adequate treatment for 2 weeks they can come out of isolation. Some countries and some physicians start with quadruple therapy including ethambutol as part of the initial regimen. This length of treatment (espe cially since patients may feel better before the end of treatment) may lead to lack of compliance, a primary factor leading to the increase in drug resist ance, as suboptimal treatment can lead to the development of secondary drug resistance. Patients who are thought to have drug-resistant tuberculo sis may be started on the above three drugs plus ethambutol until the actual sensitivity of the isolate is determined, when an appropriate combination of drugs can be given. The contacts of patients with active tuberculosis should be screened by an X-ray or given prophy laxis if appropriate. Close contacts of children with primary tuberculosis should be screened as there is likely to be a source that should be identi fied. In many areas the prevalence of tuberculosis is highest in the disad vantaged and homeless (see above). This is also the group that has high levels of drug-resistant tuberculosis (see References: Patel, 1985). Failure of therapy either due to inappropriate treatment or lack of compliance is important in development of drug-resistant strains. Review of Antibacterial, Antifungal and Antiviral Drugs, 5th edi Murphy K, Travers P, Walport M. Consensus statement: Global bur culosis in developing countries: implications for new vaccines. Molecular genetic meth with tuberculin skin test for diagnosis of Mycobacterium tubercu ods for diagnosis and antibiotic resistance detection of losis infections in a school tuberculosis outbreak. Toll-like houses, night shelters and common hostels in Glasgow: a 5 year receptor-2 mediates mycobacteria-induced proinflammatory prospective study. ArticleId=604 Bernd Sebastian Kamps and Patricia Bourcillier: Global Tuberculosis Control Report 2008, World Health tuberculosistextbook. Which of the following are typical signs of pulmonary True (T) or False (F) for each answer statement, or by tuberculosis? Case 24 Neisseria gonorrhoeae A 15-year-old heterosexual male was brought to the coming to the hospital when she developed fever, shaking emergency room by his sister. Her symptoms worsened dysuria and noted some pus-like? drainage in his and she presented with fever of 42? Urine abdominal pain, and a swollen right knee, with blood appeared clear and urine culture was negative, although pressure 120/80 and pulse 150/min and regular. The date urinalysis was positive for leukocyte esterase and multiple of her last menstrual period, which was described as white cells were seen on microscopic examination of normal, was 1 week before admission. He gave a history of being sexually active with five oriented as to time, person, and place. He claimed that he examination was unremarkable except for tender and his partners had not had any sexually transmitted abdomen and rigidity, and decreased bowel sounds; the diseases. His physical exam was significant for a yellow right knee was red, hot, tender, and swollen. A examination showed some white discharge of the cervical Gram stain of the discharge was performed in the os (Figure 3) A swab was obtained from her cervix for emergency room (Figure 2). He was asked to provide the names and addresses of his Laboratory findings: sexual partners to the Health Department so that they? In many cases infection is asymptomatic, but may cause painful urination or a purulent discharge, as seen here. In severe cases it may also cause inflammation of the testicles and prostate gland, and infertility. Gram stain of a cervical smear showing extracellular and intracellular gram-negative diplococci. The cocci are often found in pairs where their adjacent sides are flattened giving them a coffee bean appearance. Their habitat is the mucous membranes of mam mals and many species are commensals of these surfaces. Neisseria are oxidase-positive, catalase positive, and produce acid from a variety of sugars by oxidation. The protein PilC is located at the tip of the pilus and is the adhesin that mediates initial attachment of the bacterium to the surface of mucosal epithelium. By recombination of pilS sequences into the pilE gene the bacterium can express a high number of antigenically distinct pili. In phase variation the bacterium has the ability to turn pilus expression on or off at a high frequency. Among the outer membrane proteins are a family of opacity-associated pro teins (Opa), so named because they give rise to an opaque colony phenotype. Opa proteins are important in the ability of the organism to adhere tightly to epithelia. They also dictate the tissue tropism of the gonococcus and its ability to invade epithelial cells. There are as many as 12 genes encoding Opa proteins and they undergo phase variation such that a neisserial popu lation will contain bacteria expressing none, one or several Opa proteins. There are two hypervariable domains within the extracellular portion of the molecule that give rise to new Opa variants as a result of point mutation and by modular exchange of domains between different Opa proteins. The Opa proteins of the gonococcus and the meningococcus can be divided into two major groups based on the cellular receptors to which they bind. However, neisserial porins can inhibit neutrophil actin polymerization, degranulation, expres sion of opsonin receptors, and the respiratory burst. While it is logical to assume that IgA1 protease contributes to the viru lence of the gonococcus by subverting the protective effects of sIgA it should be realized that half of sIgA is of subclass 2 that is resistant to IgA1 protease. Moreover, it has been demonstrated that experimental urethral infections of male volunteers with an IgA1 protease-negative mutant of N. A role for IgA1 protease may lie in its ability to cleave lysosome-associated mem brane protein 1 (h-lamp-1). As their name implies h-lamp-1and h-lamp-2 are found in the membranes of mature lysosomes but also in the mem branes of phagosomes/endosomes. Their functions are not fully under stood but they are thought to protect the membrane from the action of degradative enzymes within the lysosome and appear to be required for fusion of lysosomes with phagosomes. It has been shown that gonococcal IgA1 protease can cleave the less glycosylated form of h-lamp-1 found in epithelial cell phagosomes/endosomes, which may enable the bacteria to escape into the cytosol of the cell and prolong their intracellular survival. Entry and spread within the body In uncomplicated gonorrhea the bacteria adhere to urethral epithelium of males and to the cervical epithelium and urethral epithelium of females. From this site the gonococci may seed the bloodstream and from there the joints and skin. In women the cervical infection may ascend to the fallopian tubes (salpingitis), which can lead to scarring, ectopic pregnancy, sterility, and chronic pelvic pain. Person to person spread the gonococcus is a sexually transmitted pathogen and it is acquired and spread horizontally (person to person) by vaginal, anal or oral intercourse.
The hepatic architecture 3 usually remains intact antibiotics for sinus infection and sore throat buy 100 mg nitrofurantoin free shipping, and little evidence of hepatic immune-mediated antibiotic resistance results from purchase nitrofurantoin 100mg overnight delivery. Acute renal failure is associated with (50 to 100 mg/mL and a normal glucose level virus 76 generic 100mg nitrofurantoin free shipping. Renal Live leptospires are placed on a slide infection minecraft server discount nitrofurantoin 100 mg fast delivery, and the highest biopsy demonstrates acute interstitial nephritis infection prevention jobs buy generic nitrofurantoin 100 mg on line, and serum dilution at which more than 50% of the spiro immune-complex glomerulonephritis may also be seen bacteria jokes for kids cheap 50 mg nitrofurantoin overnight delivery. This hemorrhagic pneumonia is as 3 days into the illness antibiotics queasy buy discount nitrofurantoin online, but usually take 2 weeks 5w infection generic 100 mg nitrofurantoin visa, and generally associated with a bloody cough, and chest continue to rise for 3 to 4 weeks. A single titer above 1:800 in combination endothelium and intra-alveolar hemorrhage. Cardio with appropriate symptoms is considered indicative of vascular collapse can develop suddenly. The mortality active disease, and a single titer of 1:200 or a persistent rate for severe leptospirosis ranges from 5% to 40%. In severe disease, penicillin detected after 1 to 2 weeks, but can take up to treatment has been shown to reduce the duration of ill 3 months. For mild leptospirosis, oral doxycycline or the sensitivity of culture is low, and therefore the amoxicillin may be administered. When exposure in diagnosis must usually be made by measuring acute endemic areas is anticipated, prophylaxis with oral and convalescent antibody titers. Some strains?for example, Rick diagnostic),titer above 1:800 plus symptoms ettsia rickettsii?produce a phospholipase that dis indicates active disease, 1:200 is suggestive. Other strains immunoglobulin M antibodies is commer multiply and survive within the phagolysosome by cially available and has good sensitivity and blocking the release of toxic enzymes into the speci? Treat with intravenous penicillin, ampicillin, or rickettsial diseases are spread to humans by arthro ceftriaxone for severe disease, oral doxycycline pods: ticks, mites, lice, and? It occurs throughout the United States, Mex are ingested by adjacent cells, forming plaques of ico, and Central and South America. Small endemic areas are ated immunity, resulting in infiltration of lympho also found in Long Island and Cape Cod. In the south, the dog to endothelial and vascular smooth muscle cells results tick (Dermacentor variabilis) is the primary vector, in a vasculitis that can involve the lungs, heart, and and in states west of the Mississippi the wood tick central nervous system. Discrete areas of hemorrhage (Dermacentor andersoni) is primarily responsible for can be found in these organs and also in the skin, transmitting disease. A recent outbreak in Arizona was intestine, pancreas, liver, skeletal muscle, and kidneys. Decreased intravascu After the tick has attached to the host for between lar volume can induce antidiuretic hormone secretion several hours and a day, it injects the rickettsiae into and hyponatremia. Once exposed to the warmer temperature cipitate acute tubular necrosis and renal failure. Acute onset of nonspecific symptoms: fever, discharged with a diagnosis of viral gastroenteritis. Four days later, she was seen at a second emergency Abdominal pain may mimic cholecystitis or room with complaints of persistent fever, anorexia, appendicitis. Spotted-fever group rickettsiae were detected by A rash usually develops within 5 days of the onset immunohistochemical staining of autopsy speci of illness, and in case 13. On questioning, the parents reported that their 10% of patients, a rash may never appear. Patients often seek medical attention ticks had been frequently observed on the family?s before the rash develops, and therefore, as in the above pet dogs and often were manually removed by case, the physician may fail to consider the diagnosis. As the disease progresses, headache may become an increasingly prominent complaint. Conjunctivitis may be noted, complain of fever, headache, malaise, myalgias, and and fundoscopic examination may reveal manifestations nausea. Respi cholecystitis, appendicitis, or bowel obstruction?or as ratory complaints may become prominent, and chest in case 13. In severe cases, gangrene of the digits can also Therapy with doxycycline is the treatment of develop as a consequence of occlusion of small arterioles. Transaminase values and bilirubin levels least 3 days after the patient has defervesced. A diffuse macu the development of petechial skin lesions may raise the lar-papular rash develops within 3 to 5 days of the onset possibility of meningococcemia or leptospirosis. During the spring and summer months, patients in endemic areas must always be treated for Rocky Mountain spotted fever pending culture results. Serology provides a retrospective diagnosis: Proteus vulgaris are not only nonspecific, but also indirect immuno? Mortality has been reported as 22% untreated, disease responds rapidly to antibiotic therapy, and 6% with treatment. The number of skin lesions varies, and they can involve the face, mucous membranes, palms, and 1. The disease spontaneously resolves within 2 to ettsia conorii, which is clinically similar to Rocky Mountain spotted fever: 3 weeks and is never fatal. Treatment with doxycycline or tetracycline is associated with resolution of symp a) Forms a black eschar called a tache noire at toms within 24 to 48 hours. This group of diseases received the name typhus? because the illness caused by species of Rickettsia that clinically mimics typhoid fever (see Chapter 8). This disease, called African this disease has been called louse-borne typhus? and tick-bite fever, is found mainly in rural regions of epidemic typhus. The disease is usually mild, but can be associated with the louse harbors high concentrations of Rickettsia persistent neuropathy. When unwitting host scratches the site and inoculates the mouse populations are reduced by extermination infected feces into the wound or onto mucous mem campaigns, the mites are more likely to infest humans branes. This disease is not considered by the end of the 1980s, infections have been reported many U. Rare cases have been reported in ico, where it may be initially mistaken for Dengue the eastern and central United States. Rickettsialpox is also found in South Africa, thought to have been transmitted by lice or? The prog macular, but quickly progress to a maculopapular nosis for Brill?Zinsser disease and? Peripheral gangrene can much better than for primary louse-borne typhus, develop as a consequence of small-vessel occlusion. Central nervous system involvement can lead to A third form of typhus called scrub typhus is drowsiness and confusion, and in severe cases, grand caused by R. These Louse-borne typhus has been associated with 30% to insects crawl on vegetation and then attach themselves 70% mortality. This disease is most often contracted by agricultural workers and military personnel in endemic areas. The incubation period is similar to that of the other rickettsial diseases (6 to 21 days); however, the onset is usually gradual rather than sud About the Epidemiology, Pathogenesis, den. Headache, high fever, chills, and anorexia are the and Clinical Manifestations of Typhus most common symptoms. The once-popular prowazekii, milder, but similar to primary Weil?Felix Proteus agglutination test is no longer disease. In a) Found in Japan, eastern Asia, Australia, and some regions in which antibiotic resistance has devel some Paci? Early treatment aborts the antibody chigger bite site in half of patients; rash response, and as a consequence, relapse may occur common. Finally, it induces clustering of transferrin receptors in the phagolyso Both species of Ehrlichia are transmitted to humans some membrane, allowing it to compete effectively for by ticks, and the seasonal nature of these diseases is iron, a vital nutrient for bacterial growth. Most teria divide by binary fusion, they cluster together, cases of human monocytotropic ehrlichiosis are asso forming intracellular inclusions called morulae. This tick also infests the whitetail deer, (also called neutrophils or granulocytes) and uses the natural reservoir for E. Both pathogens not only invade been estimated to be 5 per 100,000 population; peripheral leukocytes, but also infect the bone mar however, in certain endemic areas, incidences as high as row, causing disruption of the normal maturation 660 per 100,000 have been reported. In addition to processes and blocking production of leukocytes, red hikers and outdoor workers, golfers are at risk for con blood cells, and platelets. Human granulocytotropic anaplasma was first reported in 1994, and therefore the understanding of its epidemiology is evolving. Presumptive diagnosis must be made by clinical ers, outdoor workers, and golfers are at risk. Weil?Felix Proteus agglutination is no longer transmits Lyme disease and babesiosis. Treat with doxycycline or chloramphenicol; Massachusetts, Connecticut, New York, and patient may relapse, requiring re-treatment. Both forms of Ehrlichia present with the grad ual onset of fever, chills, headache, myalgias, anorexia, A 49?year-old white man presented to the hospital and malaise. Fever mental status, coma, and seizures are accompanied by increased to between 39. The granulocytotropic form can also be asso An epidemiologic history indicated that the ciated with respiratory insuf? Rhabdomyolysis patient was an avid hunter and had been hunting has also been described. Meningoencephalitis has not with his father on several occasions during the last been described in granulocytotropic anaplasma. Hypotension can develop pneumonia?that had developed at the same time as with either infection and mimic other forms of his current illness. He appeared epidemiology strongly suggested the diagnosis of septic and somewhat lethargic and inattentive. Tender cervical lymphadenopathy was noted, but Platelet counts can drop below 20,000/mm3 in severe the neck was supple. A few hyperpigmented macular disease and can be associated with gastrointestinal lesions over the anterior shins were observed, but 3 bleeding. If the diagnosis of Ehrlichia is being considered, a the patient was treated with doxycycline and Wright stain of the peripheral blood and a buffy coat defervesced within 48 hours. One week after hospital smear should be carefully examined for the presence discharge, his serum IgG and IgM titers came back of morulae. These intracellular inclusions are seen in the peripheral monocytes of only a small percentage positive for E. The percentage of granulocytes con taining morulae varies from 1% to 44%, with higher Case 13. Incubation period is 7 days, and mortality is 5% (mainly elderly and immunocompromised). See color image on color plate 2 ciency, rhabdomyolysis, and neutropenia resulting in gram-negative sepsis. As in rickettsiosis, serologic testing of cases of the monocytic form, but in 2% to acute and convalescent serum is the usual method for 11% of cases of the granulocytic form. Titers above 1:64, combined with a rise of at least a b) Moderate transaminase elevations are seen. Chloramphenicol has no either oral or intravenous chloramphenicol (500 mg activity in vitro, and therefore doxycycline is four times daily) is also effective, even though in vitro also recommended for children. Because of these concerns, doxy cycline is preferred over chloramphenicol in children (see Table 13. Q fever is rare in the United States, 20 to 60 Q fever is usually a self-limiting disease; however, cases being reported annually. Outbreaks occur world the occasional patient who develops Q fever endo wide, but may be missed because of the nonspeci? In some areas, the incidence of Q fever has been estimated to be 50 per 100,000 population. About the Epidemiology and When symptoms are reported, most patients develop a Pathogenesis of Q fever self-limiting? Disease is rare in the United States, and is more Some patients complain of a nonproductive cough, and commonly seen in Spain, France, England, a few rales may be detected on pulmonary exam. Hepatitis may be asymptomatic or be associ a) Organism is excreted in urine, feces, birth products of the animals. Liver biopsy typi b) Placenta is highly infectious,and aerosolized cally reveals doughnut-like granulomas consisting of a organisms survive for prolonged periods. Coxiella burnetii is a small, pleomorphic gram common manifestations include a maculopapular rash negative rod that changes its outer lipopolysac (10% of patients), myocarditis, and pericarditis (1%), charides: and meningitis or encephalitis (1%). A chronic infection persisting for longer than b) Phase I outer antigens when infecting the host. Enters the host through the respiratory tract ily involves the heart, causing symptoms of subacute and survives within phagolysosomes of bacterial endocarditis. Most cases of endocarditis develop in a) Induces mononuclear cell infiltration, patients with valvular damage or a prosthetic valve. Valve replacement is commonly required as a consequence of severe valve dysfunction, and mortality in Q fever endocarditis is high (65% to 45%). However, if untreated, infection is asso Legionella and Francisella, and is a proteobacteria. The ability of the fluorescence antibody testing remains the primary organism to hide within these acidic compartments method of diagnosis. In and IgA (above 1:100) antibody titers against phase I patients with damaged heart valves, C. Diagnosis is made by determining Cat scratch disease is most commonly contracted by immunoglobulin G (IgG) and M (IgM) antibod young people under the age of 21 years. Kittens have a very high c) Polymerase chain reaction is sensitive and incidence of asymptomatic bacteremia with Bartonella speci? About the Epidemiology b) Treat with doxycycline and hydroxychloro quine for 18 months to 4 years or life for of Bartonella Infections chronic endocarditis. Cat scratch disease is caused by Bartonella henselae: a) Transmitted primarily by young cats and,less commonly, by cat? Tetracyclines have been b) Common throughout North America; higher shown to shorten the duration of fever in acute disease incidence in warm, humid areas. In cells and multiply within a vacuole, forming intracellular addition to cat scratches, this disease may be transmit clusters similar to the morulae of Ehrlichia. The other species that Because Bartonella grows in both the intracellular and causes the latter disease, B. It is transmitted by human body lice (Pedicu granulomatous reaction consisting of macrophages and lus humanus) and causes disease in areas where sanitation histiocytes, and an acute in? Bar tonella enter the host through a break in the skin caused A 21-year-old white man presented to the emergency by a cat scratch or insect bite. The bacteria multiply at room with a 2-hour history of severe right lower this site and subsequently spread to the local lymphatic abdominal pain, nausea, vomiting, and loose stools. His abdomen was lar and other surface proteins mediate attachment to red soft and nontender;normal bowel sounds were heard. Emergency surgical exploration revealed enlarged, matted right inguinal lymph nodes. Induces both a granulomatous and an acute inflammatory reaction that attracts Cat scratch disease usually presents as a single enlarged, polymorphonuclear leukocytes and prevents warm, and painful lymph node near the site of skin inoc dissemination. Less common manifestations include optic neuritis, encephalopathy that can result in About the Clinical Manifestations seizures and coma, lytic bone lesions, granulomatous lesions of the liver and spleen, pneumonia, erythema of Cat Scratch Disease nodosum, and thrombocytopenic purpura. Bacillary Angiomatosis a) Axillary node is most common,but the involved Bacillary angiomatosis develops predominantly in indi node depends on the site of inoculation. Rarer manifestations include conjunctivitis, encephalopathy, and lesions in the liver and the skin lesions usually begin as cluster of small red spleen. They can be mistaken for Kaposi?s sarcoma, pyogenic granuloma, cherry angiomas or hemangiomas. Skin biopsy reveals multiple small blood vessels, enlarged acute lymph node swelling that caused the sudden onset endothelial cells, and polymorphonuclear leukocyte of severe pain, raising the possibility of a strangulated in? Enlargement of a single node is the rule (85% disease has been called bacillary peliosis. Epitrochlear, supraclavicular, submandibular, and inguinal are other likely sites. The lymphadenopathy usually resolves over a period of 1 to 4 months, but can persist for several years if not treated with antibiotics. About the Clinical Manifestations On careful questioning, the patient may report a of Bartonella quintana skin lesion in the region where the lymph node drains. Organism is the major cause of bacillary develops that becomes erythematous and then papular. Bacteremic illness is rare (seen in some home phadenopathy in about half of cases. Conjunctivitis less individuals); characterized by recurrent occasionally develops when the eye is the portal of entry, 5-day fever, shin pain, malaise. Symptoms of fever, malaise, and bone pain involv About the Diagnosis and Treatment ing the anterior shins usually begin 5 to 20 days after of Bartonella Infections exposure. Organisms grow on conventional media, but common presentation, and it is the basis for the name slowly; clinical laboratory must be alerted. Blood cultures frequently yield false negatives, continue to have asymptomatic bacteremia lasting because organisms adhere to the sides of the weeks to months. Biopsies are frequently unnecessary; Warthin? should be considered in cases of culture-negative Starry stain shows black rods. Treatment: Bartonella grows slowly on fresh blood agar, rabbit-heart a) Azithromycin is the drug of choice, 5 days; infusion agar, and chocolate agar. If Bartonella is alternatives are clarithromycin, doxycycline, suspected, the physician should contact the clinical or cipro? Oral clarithromycin, oral doxy ally not required for diagnosis, and the histopathology cycline, or oral cipro? Pallisading epithelioid cells are com (500 mg daily) or gentamicin (5 mg/kg daily) combined monly seen, and a positive Warthin?Starry silver stain with oral or intravenous rifampin (600 mg daily) are demonstrating black bacilli provides strong evidence for likely to be the most effective regimen. The skin test was pre typical? or viously considered to be a useful diagnostic tool, but it atypical? is no longer recommended.
Laboratory criteria for diagnosis Demonstration of malaria parasites in blood films (mainly asexual forms) antibiotic resistance conjugation 50mg nitrofurantoin otc. In Africa infection xp king buy nitrofurantoin 50mg otc, tickborne relapsing fever and rabies are often mis-diagnosed as malaria antibiotics pancreatitis generic nitrofurantoin 100mg mastercard. The typical malarial paroxysm begins with rigors lasting 1 to 2 hours antibiotic resistant bv order nitrofurantoin 100 mg on-line, followed by high fever antibiotics for sinus infection in pregnancy buy 50mg nitrofurantoin visa. Plasmodium malariae persists without symptoms in the blood antimicrobial conference 2013 buy nitrofurantoin in united states online, rather than the liver virus hitting schools discount 100 mg nitrofurantoin otc. Malaria in Haiti Time and Place: Highest rates are registered during May to November antimicrobial infection nitrofurantoin 50 mg fast delivery. The true incidence of malaria has been estimated at approximately 200,000 cases per year 41 (2010 publication) Individual years: 42 2010 11 cases (including 8 expatriates) were identified following an earthquake. Pseudomonas aeruginosa: aerobic gram-negative bacillus (virtually all cases) Reservoir Human Vector None Vehicle Endogenous Incubation Period Variable Diagnostic Tests Culture ofotic exudate and biopsy material. Synonyms Clinical 1 Severe pain and tenderness in the mastoid area are accompanied by drainage of pus from the external canal. Phasmidea, Filariae: Mansonella ozzardi Reservoir Human Vector Fly (black fly = Simulium) or midge (Culicoides) Vehicle None Incubation Period 5m 18m (range 1m 2y) Diagnostic Tests Identification of microfilariae in skin snips or blood. Filaria ozzardi, Mansonella ozzardi, Microfilaria bolivarensis, Ozzardiasis, Tetrapetalonema ozzardi. Prevalence surveys: 3 16% were reported in Bayeux (1980 publication) 4 Mansonella ozzardi infection has been identified among Haitian refugees in Florida. Paramyxoviridae, Paramyxovirinae, Morbillivirus: Measles virus Reservoir Human Vector None Vehicle Droplet Incubation Period 8d 14d Diagnostic Tests Viral culture (difficult and rarely indicated). Masern, Massling, Mazelen, Meslinger, Morbilli, Morbillo, Rubeola, Rugeole, Sarampion, Sarampo. Acute illness: Symptoms begin to appear about 10 to 12 days after exposure to the virus, with fever followed by cough, rhinorrhea, and/or 1 conjunctivitis. Complications: 3 Complications of measles include diarrhea, otitis media (10%), pneumonia (5%), encephalitis (0. Measles pneumonia accounts for approximately 17% of bronchiolitis obliterans in children (Beijing, 2001 to 2007) 9. Individual years: 2001 37% of all cases for the Americas Notable outbreaks: 2000 An outbreak (992 cases, or 57% of all cases for the Americas region) was reported most from Artibonite and 10 metropolitan Port-au-Prince. Burkholderia pseudomallei An aerobic gram-negative bacillus Reservoir Soil Water Sheep Goat Horse Pig Rodent Monkey Marsupial Vector None Vehicle Water: Contact, ingestion, aerosol Breast milk (rare) Incubation Period 3d 21d (range 2d 1y) Diagnostic Tests Culture of blood, sputum, tissue. X at least 14 days May be combined with Typical Adult Therapy Sulfamethoxazole/trimethoprim p. X at least 14 days May be combined with Typical Pediatric Therapy Sulfamethoxazole/trimethoprim p. May present as: lymphangitis with septicemia; or fever, cough and chest pain; or diarrhea; bone, Clinical Hints central nervous system, liver and parotid infection are occasionally encountered; case-fatality rate 10% to over 50% (septicemic form). Renal failure occurs in up to one-third of hospitalized patients with melioidosis, and carries a poor prognosis. Most patients with overt infection present with pneumonia which may include pulmonary nodules, consolidation, necrotizing 31 lesions, pleural effusion, pleural thickening and mediastinal abscesses. In nonendemic regions, patients present with reactivated disease occurring months to years after initial exposure to the organism. Aseptic meningitis, Encephalitis viral, Meningite virale, Meningitis, viral, Meningo-encefalite virale, Viral encephalitis, Viral meningitis. Typical Adult Therapy Bactericidal agent(s) appropriate to known or suspected pathogen + dexamethasone Typical Pediatric Therapy As for adult H. Potential: (bacterial meningitis case): a child with a clinical syndrome consistent with bacterial meningitis. As a group, the bacterial meningitides are characterized by signs of sepsis, fever, headache, meningismus and neutrophilic 1 2 pleocytosis. Meningococcal infection, cases Notes: Individual years: 4 1995 Included 55 fatal cases. Notable outbreaks: 1994 An outbreak (100 cases, approximate 9 fatal) of group C meningococcal infection was reported in Quanaminthe (Northeast Department) References 1. Microspora: Enterocytozoon, Encephalitozoon (Septata), Vittaforma (Nosema), Agent Pleistophora, Trachipleistophora, et al. Reservoir Rabbit Rodent Carnivore Non-human primate Fish Dog Bird Vector None Vehicle? Brachiola, Encephalitozoon, Enterocytozoon, Microsporidium, Nosema, Pleistophora, Trachipleistophora, Vittaforma. Moniliformida: Moniliformis moniliformis, Oligocanthorhynchida: Agent Maracanthorhynchus hirudinaceus. Reservoir Pig (Maracanthorhynchus), rat and fox (Moniliformis), Vector None Vehicle Insect (ingestion) Incubation Period Unknown presumed 15 to 40 days Diagnostic Tests Identification of worm in stool. Pyrantel pamoate has been used against Moniliformis moniliformis Typical Adult Therapy 11 mg/kg p. Pyrantel pamoate has been used against Moniliformis moniliformis Typical Pediatric Therapy 11 mg/kg p. Acanthocephalan worms, Macracanthorhynchus, Moniliform acanthocephalan, Moniliformis moniliformis. Typical Adult Therapy Respiratory isolation; supportive Typical Pediatric Therapy As for adult Measles-Mumps-Rubella Vaccines Mumps Rubella Mumps Fever, parotitis, orchitis (20% of post-pubertal males), meningitis (clinically apparent in 1% to 10%), Clinical Hints oophoritis, or encephalitis (0. Bof, Epidemic parotitis, Fiebre urliana, Infectious parotitis, Kusma, Oreillons, Paperas, Parotidite epidemica, Parotiditis, Parotite epidemica, Passjuka. Acute illness: the prodrome of mumps consists of low-grade fever, anorexia, malaise, and headache. Neurological manifestations: Central nervous system involvement is the most common extrasalivary gland manifestation of this disease. Mumps Infectious Diseases of Haiti 2010 edition Epididymo-orchitis: Epididymo-orchitis is the most common extra-salivary gland manifestation in adults, developing in 20 to 30% of infected postpubertal males. Additional manifestations of mumps: 6 Other features of mumps include oophoritis, fetal wastage, migratory polyarthritis, monoarticular arthritis and arthralgia, electrocardiographic changes (with or without overt myocarditis), nephritis, thyroiditis, mastitis, prostatitis, hepatitis, cholecystitis and thrombocytopenia. Nocardia spp, Madurella mycetomatis, Actinomadura pellitieri, Agent Streptomyces somaliensis, et al Reservoir Soil Vegetation Vector None Vehicle Contact Wound Soil Incubation Period 2w 2y Diagnostic Tests Bacterial and fungal culture of material from lesion. Excision as indicated Typical Pediatric Therapy As for adult Painless, chronic, draining, fistulous subcutaneous nodule usually involving lower extremity; Clinical Hints osteolytic lesions may be noted on x-ray; usually no fever; most patients are males age 20 to 40 (ie, occupational exposure). Dark granules characterize Madurella infection, while pale colored granules are seen in Acremonium infection. Rare instances of mycetoma of the scalp due to Microsporum canis have been reported. Diagnosis is based on radiological and ultrasonic imaging, histology, culture and serology. Actinomycetes, Mycobacterium marinum An aerobic acid-fast bacillus Reservoir Fresh and salt water (eg, swimming pools, aquaria) Fish (ornamental, salmon, sturgeon, bass) Vector None Vehicle Water per areas of minor skin trauma Incubation Period 5d 270d (median 21d) Diagnostic Tests Mycobacterial culture from lesion. Althernative Minocycline (Age >= 8) Violaceous papule, ulcer, plaque, psoriaform lesion; onset weeks after exposure (swimming pool, Clinical Hints aquarium); commonly involves the elbow, knee, hand or foot. Actinomycetes, Mycobacterium scrofulaceum An aerobic acid-fast bacillus Reservoir Water (lakes, rivers) Soil Raw milk Plant material Vector None Vehicle Water Soil? Through areas of minor trauma Incubation Period Unknown Diagnostic Tests Culture of tissue or aspirates. Drugs (Isoniazid Rifampin streptomycin Cycloserine) are rarely indicated Typical Pediatric Therapy As for adult Painless lymphadenopathy, most commonly unilateral and submandibular (true tuberculosis involves Clinical Hints the lower neck and produces a strongly positive tuberculin reaction and/or suggestive chest X ray). Synonyms Clinical Mycobacterium scrofulaceum is a common cause of lymphadenitis, most commonly among children ages 1 to 3 years. An aerobic acid-fast bacillus Reservoir Water Soil Fish Mammal Bird Vector None Vehicle Air Water Contact Ingestion Trauma Incubation Period Variable Microscopy & culture of tissue, secretions, blood. Inform laboratory if Diagnostic Tests suspected Drug, route and duration appropriate to clinical setting and species [in Therapy module, scroll Typical Adult Therapy through upper left box] Typical Pediatric Therapy As for adult Pneumonia, or chronic granulomatous infection of various tissues; systemic disease may complicate Clinical Hints immune suppression; M. Mycobacterium abscessus, Mycobacterium avium, Mycobacterium avium-intracellulare, Mycobacterium immunogenum, Mycobacterium jacussii, Mycobacterium xenopi, Segniliparus. Mycobacterium kansasii infection is characterized by productive cough, dyspnoea, and chest pain. Mycobacterium malmoense infection is usually characterized by pulmonary disease suggestive of tuberculosis, or pediatric 9 cervical lymphadenopathy. Note: Over 110 species of Mycobacterium have been associated with human infection. Mycoplasmatales Mycoplasma genitalium, Mycoplasma hominis, Mycoplasma Agent fermentans, Mycoplasma penetrans, Ureaplasma urealyticum Reservoir Human Vector None Vehicle Secretion, Sexual transmission Incubation Period Unknown Diagnostic Tests Culture (urine, pharynx). Infection by hemotrophic Mycoplasma species (formerly Epirythrozoon) is characterized by fever, anemia and hemolytic 31 jaundice. Mycoplasma pneumoniae Reservoir Human Vector None Vehicle Droplet Incubation Period 6d 23d Diagnostic Tests Culture (sputum, throat). Typical Adult Therapy Removal of maggot Typical Pediatric Therapy As for adult Pruritic or painful draining nodule; fever and eosinophilia may be present; instances of brain, eye, Clinical Hints middle ear and other deep infestations are described. Streptococcus pyogenes, Clostridium perfringens, mixed anaerobic and/or gram Agent negative bacilli Reservoir Human Vector None Vehicle Endogenous Incubation Period Variable Diagnostic Tests Clinical features. Hyperbaric oxygen in Typical Adult Therapy more severe infections Typical Pediatric Therapy As for adult At least 7 syndromes in this category: most characterized by local pain and swelling, skin Clinical Hints discoloration or edema, gas formation, foul odor and variable degrees of systemic toxicity. Clinical forms of necrotizing skin and soft tissue infection (in alphabetical order): Clostridial cellulitis usually follows local trauma or surgery, and has a gradual onset following an incubation period of 3 or more days. Infected vascular gangrene is a complication of peripheral vascular insufficiency and has a gradual onset beginning 5 or more days after the initiating event. Non-clostridial anaerobic cellulitis is usually associated with diabetes mellitus or a preexisting local infection. Synergistic necrotizing cellulitis is associated with diabetes, renal disease, obesity or preexisting perirectal infection. Clostridium septicum (occasionally Clostridium tertium, Clostridium sporogenes, Agent Clostridium sordellii or Clostridium tertium) Reservoir Human Vector None Vehicle Endogenous Incubation Period Unknown Diagnostic Tests Typical findings in the setting of neutropenia. Broad spectrum antimicrobial coverage, which should include clostridia and Pseudomonas Typical Adult Therapy aeruginosa. Role of surgery is controversial Broad spectrum antimicrobial coverage, which should include clostridia and Pseudomonas Typical Pediatric Therapy aeruginosa. Role of surgery is controversial Fever, abdominal pain, diarrhea (occasionally bloody) and right lower quadrant signs in a neutropenic Clinical Hints (leukemic, etc) patient; may spread hematogenously to extremities; case-fatality rate 50% to 75%. An aerobic gram positive bacillus (acid-fast using special Agent technique) Reservoir Soil Vector None Vehicle Air Dust Wound Contact Incubation Period? Typical Adult Therapy Sulfamethoxazole/trimethoprim dosage and duration of therapy appropriate to clinical severity Typical Pediatric Therapy As for adult Pneumonia, lung abscess, brain abscess, or other chronic suppurative infection; often in the setting Clinical Hints of immune suppression. Typical Adult Therapy Local and systemic antimicrobial agents appropriate for species and severity Typical Pediatric Therapy As for adult Proptosis, chemosis, extraocular palsy, or hypopyon associated with sinusitis, bacteremia, eye Clinical Hints trauma or surgery. Involves the eye (endophthalmitis); periosteum (periorbital infection); orbit (orbital cellulitis); orbit + eye (panophthalmitis). Bacterial keratitis, Ceratite, Cheratite, Endophthalmitis, Eye infection, Keratite, Keratitis, Orbital infection, Panopthalmitis, Queratitis. Keratitis can be caused by viruses (Herpes simplex, zoster, smallpox), bacteria, fungi, protozoa (Acanthamoeba) or helminths (Onchocerca volvulus) 5. Poxviridae, Parapoxvirus: Orf virus Reservoir Sheep Goat Reindeer Musk ox Vector None Vehicle Contact Infected secretions Fomite Incubation Period 3d 6d (range 2d 7d) Diagnostic Tests Viral culture (skin lesion or exudate). Typical Adult Therapy Supportive Typical Pediatric Therapy As for adult Skin pustule or ulcer following contact with sheep or goats; most lesions limited to finger or hand; Clinical Hints heals without scarring within 6 weeks. Chlamydiaceae, Chlamydiae, Chlamydophila [Chlamydia] psittaci Reservoir Parakeet Parrot Pigeon Turkey Duck Cat Sheep Goat Cattle? Dog Vector None Vehicle Bird droppings Dust Air Aerosol from cat [rare] Incubation Period 7d 14d (range 4d 28d) Diagnostic Tests Serology. Headache, myalgia and pneumonia, often with relative bradycardia, hepatomegaly or splenomegaly; Clinical Hints onset 1 to 4 weeks following contact with pigeons, psittacine birds or domestic fowl; case-fatality rate without treatment = 20%. Chlamydophila abortus, Chlamydophila psittaci, Ornitose, Papegojsjuka, Parrot fever, Psitacosis, Psittacosis, Psittakose. A more common presentation consists of atypical pneumonia, with nonproductive cough, fever, headache and pulmonary 2 infiltrates. Chlamydophila abortus, a related species which affects goats, cattle and sheep, had been associated with rare instances of abortion, stillbirth and even maternal death in humans. Staphylococcus aureus, facultative gram-negative bacilli, Candida albicans, Agent etc Reservoir Endogenous Introduced flora (trauma, surgery) Vector None Vehicle Trauma Hematogenous Extension from other focus Incubation Period Variable Diagnostic Tests Radiography, including bone scan. Typical Adult Therapy Systemic antimicrobial agent(s) appropriate to known or suspected pathogen. Surgery as indicated Typical Pediatric Therapy As for adult Limb pain or gait disturbance; obscure fever; prior skin infection; may be hematogenous, or arise Clinical Hints from contiguous (soft tissue, joint) infection; X-ray changes are not apparent for at least 10 days in acute infection. Diabetes and vascular insufficiency: Usually mixed infection (Staphylococcus aureus, Staphylococcus epidermidis, Gram negative bacilli, Anaerobes). Hematogenous: Usually single organism (Staphylococcus aureus, Enterobacteriaceae). Typical Adult Therapy Antimicrobial agent directed at likely pathogens Typical Pediatric Therapy As for adult Vaccine Pneumococcal conjugate Acute bacterial otitis media often represents the final stage in a complex of anatomic, allergic or viral Clinical Hints disorders of the upper airways; recurrent or resistant infections may require surgical intervention. Reservoir Human Vector None Vehicle Droplet Incubation Period 3d 8d Diagnostic Tests Viral culture (respiratory secretions). Typical Adult Therapy Supportive Typical Pediatric Therapy As for adult Upper respiratory infection often croup or laryngitis. Parvoviridae, Parvovirinae: Erythrovirus B19 Reservoir Human Vector None Vehicle Droplet Incubation Period 4d 14d (range 3d 21d) Serology. Nucleic acid amplification (testing should be reserved for the rare instance of complicated Diagnostic Tests infection). Typical Adult Therapy Supportive Typical Pediatric Therapy As for adult Erythema infectiosum (erythema of cheeks; lacelike or morbilliform rash on extremities); febrile Clinical Hints polyarthralgia, or bone marrow aplasia/hypoplasia may be present. Parvovirus B19 infection Infectious Diseases of Haiti 2010 edition during the preceding 1 to 7 days. Intrapartum infections: Intrauterine infections can lead to specific or permanent organ defects in the fetus (e. Reservoir Human Vector Louse Vehicle Contact Incubation Period 7d Diagnostic Tests Identification of adults and "nits. Crab louse, Lausebefall, Pediculose, Pediculus capitus, Pediculus corporis, Pedikulose, Phthirus pubis, Pidocci. Linguatula serrata Reservoir Herbivore Vector None Vehicle Meat (liver or lymph nodes of sheep/goat) Incubation Period Unknown Diagnostic Tests Identification of larvae in nasal discharge. Typical Adult Therapy No specific therapy available Typical Pediatric Therapy As for adult Pharyngeal or otic itching, cough, rhinitis or nasopharyngitis which follows ingestion of undercooked Clinical Hints liver. Streptococcus pneumoniae, Staphylococcus aureus, et al Reservoir Human Vector None Vehicle Endogenous Incubation Period Variable Ultrasonography and cardiac imaging techniques. Typical Adult Therapy Antimicrobial agent(s) appropriate to known or anticipated pathogen. Escherichia coli, other facultative gram negative bacilli, Candida albicans, Agent et al Reservoir Human Vector None Vehicle None Incubation Period Variable Diagnostic Tests Urine and blood culture. Synonyms Clinical Symptoms may be overt or subtle, and limited to unexplained fever; indeed, 33% of such lesions are first diagnosed at autopsy. Various (often mixed anaerobic and aerobic flora) Reservoir Human Vector None Vehicle Endogenous Incubation Period Variable Diagnostic Tests Culture of drainage material. Typical Adult Therapy Surgical drainage and antibiotics effective against fecal flora Typical Pediatric Therapy As for adult Anal or perianal pain with fever and a tender mass suggest this diagnosis; granulocytopenic patients Clinical Hints commonly develop small, soft and less overt abscesses often due to Pseudomonas aeruginosa. Synonyms Clinical 1 Perirectal abscess is a self-defined illness usually associated with overt local pain, swelling, tenderness and fluctuance. Various (often mixed anaerobic and aerobic flora) Reservoir Human Vector None Vehicle Endogenous Incubation Period Variable Diagnostic Tests Culture of blood and peritoneal fluid. Typical Adult Therapy Antimicrobial agent(s) appropriate to known or anticipated pathogens. Surgery as indicated Typical Pediatric Therapy As for adult Abdominal pain and tenderness, vomiting, absent bowel sounds, guarding and rebound; diarrhea Clinical Hints may be present in children; search for cause: visceral infection or perforation, trauma, underlying cirrhosis (spontaneous peritonitis) etc. Spontaneous bacterial peritonitis is somewhat more subtle, and should be suspected when unexplained deterioration occurs 2 3 in a patient with ascites or chronic liver disease. Bordetella pertussis An aerobic gram-negative coccobacillus Reservoir Human Vector None Vehicle Air Infected secretions Incubation Period 7d 10d (range 5d 21d) Diagnostic Tests Culture & direct fluorescence (nasopharynx). Bordetella holmesii, Bordetella parapertussis, Bordetella pertussis, Coqueluche, Keuchhusten, Kikhosta, Kikhoste, Kinkhoest, Parapertussis, Pertosse, Syndrome coqueluchoide, Tos convulsa, Tos Synonyms farina, Tosse convulsa, Tussis convulsa, Whooping cough. Acute illness: Following an incubation period of 7 to 10 days (range 6 to 20) the patient develops coryza and cough (the catarrhal stage). Complications: Infants are at increased risk of complications from pertussis, while pertussis among adolescents and adults tends to be milder 5 and may be limited to a persistent cough. Human Bocavirus infection may mimic the symptoms of pertussis Parapertussis is caused by Bordetella parapertussis, and shares many of the clinical features of pertussis. Typical Adult Therapy Surgical drainage and parenteral antibiotics effective against oral flora Typical Pediatric Therapy As for adult Fever, painful swelling and displacement of the tongue, fauces and other intraoral structures; Clinical Hints dysphagia, dyspnea or jugular phlebitis may ensue in more virulent infections. Treponema carateum A microaerophilic gram-negative spirochete Reservoir Human Vector? Acute, pruritic erythematous papules which evolve to chronic, enlarging dyschromic plaques; a Clinical Hints generalized papulosquamous rash may be noted later in the illness; lesions may recur for 10 years in some cases. Results of dark field microscopy and serological tests are indistinguishable from those of syphilis. Human herpesvirus 7 has been implicated Reservoir Unknown Vector Unknown Vehicle Unknown Incubation Period Unknown Diagnostic Tests Clinical features. Typical Adult Therapy Supportive; ultraviolet B exposure is suggested Typical Pediatric Therapy As for adult 3 to 8 week illness; herald patch followed by crops of salmon-colored macules and papules; pruritus; Clinical Hints systemic symptoms rare. Synonyms Clinical Pityriasis rosea is a mild exanthem characterized by oval or round macules or papules which evolve following the appearance of a "herald patch" (80% of cases). Plesiomonas shigelloides A facultative gram-negative bacillus Reservoir Fish Animal Soil Reptile Bird Vector None Vehicle Water Food Incubation Period 1d 2d Diagnostic Tests Stool culture alert laboratory when this organism is suspected.
Microscopy Examination of sputum antibiotics for uti make me feel sick purchase genuine nitrofurantoin on line, blood virus x trailer cheap nitrofurantoin 50 mg on line, cerebrospinal fluid antibiotic nclex questions nitrofurantoin 100mg discount, and other specimens B stained by Gram?s method for gram-positive antibiotics have no effect on quizlet purchase nitrofurantoin australia, bullet-shaped diplococci can provide a rapid preliminary diagnosis antimicrobial cleanser buy nitrofurantoin 50mg without a prescription. Highly mucoid infection 10 order nitrofurantoin amex, a-hemolytic colonies are shown in Figure 4; however infection testicular safe 50mg nitrofurantoin, pneumococcal colonies frequently produce little to no capsule (nonmucoid) antibiotic 250 mg order nitrofurantoin pills in toronto. Capsule swelling and increased refractility result from the interaction of the antibody with the capsule for which it is specific. Differential diagnosis the clinical presentation and findings suggest pneumonia of bacterial etiology because of the acute onset and severity of symptoms. Pneumonia caused by viruses has a more gradual onset and is generally less severe. Optochin susceptibility test for Symptoms of viral pneumonia may include fever, dry cough, headache, and identification of S. Within 12?16 hours, other symptoms may appear, such as a-Hemolytic, gram-positive, catalase shortness of breath, sore throat, increased cough, and mucus with cough. The strain in the top streak has grown up to the disc and is resistant to optochin and, 5. The strains in the center and lower streaks Management show a zone of inhibition indicating that S. About one-third of the strains isolated in the United States are resistant to penicillin and higher rates of resistance have been observed in other countries. Unfortunately, these are the same serotypes that cause the vast majority of infections in children. Cefotaxime, ceftriaxone, and clindamycin are effective antibiotics for treating pneumonia caused by penicillin-resistant pneumococcal isolates that are susceptible to these antibiotics. Clindamycin or vancomycin is recommended when a pneumococcal isolate is resistant to cefotaxime or ceftriaxone. A 23-valent vaccine consisting of capsular polysaccharide from the 23 serotypes that are most commonly isolated from infected patients is recommended for use in children above the age of 2 years and in adults. Therefore, for children younger than 2 years of age, a 7-valent conjugate vaccine is recommended. In this vaccine the capsular polysaccharide is conjugated to a protein carrier to render it T-cell-dependent. The protein carrier used is either tetanus toxoid or diphtheria toxoid, themselves vaccine antigens. The 7-valent conjugate vaccine reduces invasive infection in children, yet has little effect on the incidence of otitis media and colonization. What is the host response to the infection and surrounded by a zone of incomplete hemolysis (a-hemolysis). How is the disease diagnosed and what is the adults is only 60% effective in the elderly and is differential diagnosis? Microscopy: examination of sputum, blood, infection in children, yet has little effect on the cerebrospinal fluid or aspirates stained by Gram?s incidence of otitis media and colonization. Versatility of pneumococcal Strepococcus pneumoniae and its close commensal relatives. Mucosal immunity induced by identification of antibiotic and vaccine targets in Streptococcus pneumococcal glycoconjugate. Clinical implications and treatment of multiresistant Streptococcus pneumoniae pneumonia. Which one of the following statements concerning the pneumococcal conjugate vaccine is correct? A 33-year-old male who developed penetrating head trauma in a motor vehicle accident. Which one of the following bacteria is the most common cause of community-acquired pneumonia? Case 36 Streptococcus pyogenes A 7-year-old boy was well until yesterday when he developed dysphagia, painful anterior lymph nodes, and a fever to 40? Examination of his head, eyes, ear, nose, and throat revealed bilateral tonsillar hypertrophy with grayish-white exudates and punctate hemorrhages (Figure 1). As for other streptococci, the catalase test is used to distinguish them from staphylo cocci, which are the other medically important genus of gram-positive cocci (see Figure 11 in the Staphylococcus aureus case for the catalase test). These are either anchored in the cytoplasmic membrane and traverse the cell wall to the outside or they are anchored Figure 2. M protein is an a-helical coiled-coil fibrillar pro form of growth is most obvious when the tein. The amino acid sequence of the extracellular portion of the molecule bacteria are obtained from liquid samples. The importance of the division of M types into two classes is in determining their propensity to cause second ary complications. While both classes cause suppurative infections and glomerulonephritis, only strains with class I M proteins cause rheumatic fever (see complications later). T antigens form the backbone of pilus-like structures that extend from the cell surface and may be involved in adhesion and invasion. It is interesting that the genes encoding the pili are found on a pathogenicity island (large Figure 3. Also located on the cell surface is the group-specific Hemolysis is caused by two exotoxins carbohydrate on which is based the Lancefield typing system for termed streptolysin O and streptolysin b-hemolytic streptococci. The structure of the capsule is identical to that of the the inoculum is stabbed below the surface mammalian intercellular matrix, thus disguising the organism. What causes the organism to become invasive following a local infection is still not fully understood. However, it has recently been suggested that clotting factors and the level of the pyrogenic exotoxin SpeB might be important. Spread via the hands can result in auto-inoculation, that is spread of the organism to additional parts of the body as well as spread to other persons. This is well illustrated in the case of pyoderma (impetigo), a highly contagious superficial skin infection seen in young children in day-care or kinder garten settings. It appears the fibronection-binding proteins and M protein are important co-operative invasins, but it is clear that other surface adhesion molecules listed in Table 1 are implicated. Fibronectin may serve as a bridging molecule between the bacterial surface and the a5b1 integrin on the host cell membrane. However, they are able to escape the early endosome, perhaps as a result of the action of the pore-forming cytolysin, streptolysin O. Streptococci are opsonized by activation of the alternate and lectin innate complement pathways and the classical pathway in the presence of anti-M protein antibodies in the plasma and tissue fluid. The hyaluronic capsule is poorly immunogenic, antiphagocytic, and serves to mask cell surface antigens from host immunity. M protein binds factor H, a regulatory protein of the alternative pathway of complement, which degrades the complement com ponent C3b, which is a potent opsonin. These cytokines mediate shock and organ failure characteristic of strepto coccal toxic shock syndrome and give rise to the rash associated with scarlet fever. Finally, the immunoglobulin-binding M-like proteins function in blocking phagocytic activity and also degrade complement C3b. Down-regulation of the pyrogenic exotoxin SpeB appears to favor cell surface accumulation of these factors. Local infections Pharyngitis occurs 24?48 hours post-exposure with sudden onset of sore throat, malaise, fever, and headache. Complications of streptococcal pharyngitis are scarlet fever and acute rheumatic fever (see Figure 1). Initially the tongue is covered with a white coating, which is lost to reveal a red, raw surface termed straw berry tongue? (Figure 5B). After about a week the rash fades and is replaced by desquamation (Figure 5C and D). Facial erysipelas manifested as Pyoderma (impetigo) is a highly contagious, superficial infection of exposed severe malar and nasal erythema and skin, typically the face, arms and legs, seen most frequently in young chil swelling. Cellulitis has no Erysipelas is an acute infection of the skin accompanied by lymphadenopa lymphatic component and exhibits nondiscrete margins. The painful, inflamed skin is raised and clearly demarcated from the surrounding healthy skin (Figure 6). Although it can occur on any part of the body the legs are a frequent site of infection because of venous insufficiency and stasis ulcerations. Cellulitis is an infection similar in nature to erysipelas except that it involves not only the skin but the connective tissues (Figure 7). Necrotizing fasciitis is a deep infection of the connective tissue that spreads along fascial planes and destroys muscle and fat. The course of the infection is rapid, often beginning with severe pain without evidence of injury or wound. Over a matter of hours there is swelling and the appearance of a spreading red or dusky blue skin discoloration, often with fluid-filled bullae (Figure 8). Flu-like symptoms such as diarrhea, nausea, fever, confusion, dizziness, and weakness are also apparent. Also, there is a migratory arthritis, subcutaneous nodules, a serpiginous, flat, painless rash (erythema marginatum), and chorea (Sydenham?s chorea). The basis for this cross-reactivity lies in the coiled-coil nature of M protein and its homology with tropomyosin, myosin, keratin, laminin, desmin, vimentin, and other coiled-coil proteins. The of the infection is rapid, often beginning target organ is the kidney, resulting in inflammation of the glomeruli, with severe pain without evidence of injury edema, hypertension, hematuria, and proteinuria. In addition, immune complexes of streptococcal antigens deposit in the glomeruli activating the comple ment cascade. Diagnosis Microscopy: Examination of infected tissues or body fluids stained by Gram?s method can provide a rapid preliminary diagnosis. The first sector of the inoculated plate should be stabbed to promote b-hemolysis (see Figure 3). These tests are based on immunological detection of the Lancefield group A wall carbohydrate antigen. The antigen is extracted from the swab using acid or an enzyme and is detected by antibody immobilized on latex beads (latex agglutination) or on a membrane (Figure 11). The image shows a blood presumptive test for identification of group A streptococci and Enterococcus species. However, it should be noted that during the last few years, erythromycin-resistant S. Streptococcal pharyngitis is self limiting, however, antibiotic therapy is indicated because it prevents the development of rheumatic fever but, interestingly, it does not appear to prevent the development of acute glomerulonephritis. Serious soft tissue infections require drainage and surgical debridement as the first line of therapy. Prevention In April 2007, the American Heart Association updated its guidelines for prevention of endocarditis and concluded that there is no convincing evi dence linking dental, gastrointestinal or genitourinary tract procedures with the development of endocarditis. The prophylactic use of antibiotics prior to a dental procedure is now recommended only for those patients with the highest risk of adverse outcome resulting from endocarditis, such as patients with a prosthetic cardiac valve, previous endocarditis, or those with specific forms of congenital heart disease. The guidelines no longer recommend prophylaxis prior to a dental procedure for patients with rheu matic heart disease unless they also have one of the underlying cardiac conditions listed above. Antibiotic prophylaxis solely to prevent bacterial endocarditis is no longer recommended for patients who undergo a gas trointestinal or genitourinary tract procedure. What is the causative agent, how does it enter opsonization and phagocytosis by means of the body and how does it spread a) within the capsule, M protein, and C5a peptidase. What is the typical clinical presentation and surrounded by a large zone of complete what complications can occur? What is the host response to the infection and in which the infected skin is painful, inflamed, its pathogenesis? Molecular basis of group A group A and group B Streptococcus: implications for reporting streptococcal virulence. Lancet Infect Dis, ulation and regulatory networks in Streptococcus pyogenes and 2005, 5: 685?694. Molecular mechanisms of adhesion, colonization, and invasion of group A streptococci. Which one of the following statements concerning pharyngitis because the disease is self-limiting. It is associated with strains causing severe systemic pharyngitis because it prevents the development of infection. Case 37 Toxoplasma gondii A 32-year-old Nigerian female was admitted to hospital having had two fits. Over about 6 months she had been obtaining over the counter treatment from the local pharmacy for oral thrush. She had a slight fever on admission, no focal neurological signs or papilledema on funduscopy. After deliberation it was considered safe and prudent to perform a lumbar puncture. There were 10 lymphocytes (normal <5), a protein of 940 mg L?1 (normal range 150?450), but no organisms. She was started on phenytoin to control fits and ceftriaxone and metronidazole to treat bacterial brain abscesses. There had been no improvement in her fever or headache and she was presumptively diagnosed with toxoplasmic encephalitis. Treatment was changed to pyrimethamine and sulfadiazine plus folinic acid to help her bone marrow. Many warm-blooded animals can serve as an inter mediate host including, for example, poultry, rodents, cattle, sheep, and pigs. These sporulate (2) and are ingested by the intermediate host when they graze on the ground 1 unsporulated oocysts (3). Humans may ingest oocysts, which passed in feces contaminate foods or water (4) or eat cysts cysts ingested by cat in infected meat (5). Within the intestine of d the intermediate host the oocysts release sporozoites that invade the intestinal 7 2 epithelium. They mature into tachyzoites i that form tissue cysts at various sites in the body (6). These may then be ingested by d cysts in tissues of intermediate hosts i cats to continue the life cycle (7). In humans tissue cysts develop in the same sporulated oocysts way as in the intermediate hosts. Within the intestine of these intermediate hosts, the oocysts release sporozoites that invade the intes tinal epithelium and multiply to form tachyzoites (Figure 4). Tachyzoites may spread to local cells or pass via the lymphatics to regional lymph nodes and then to elsewhere in the body. However, there is a predilection for lymph nodes, skeletal and car diac muscle, the brain, and the eye. At each tissue site tachyzoites enter cells and multiply to form tissue cysts, which contain bradyzoites (Figure 5). Bradyzoites in tissue cysts multiply more slowly and may pass unnoticed in tissues for prolonged periods. Humans are infected when they ingest bradyzoites in tissue cysts within uncooked or poorly cooked meat from the intermediate hosts or eat food including vegetables contam inated with cat feces and oocysts (Figure 3). The prac tice of eating undercooked meats is more common in some countries, such as France, where the prevalence of toxoplasmosis is also higher. Toxoplasmosis observed in vegetarians is presumably through eating veg etables contaminated by oocysts in the soil, which are not completely washed off. In the developing world the quality of filtration and water supplies cannot be guaranteed. Some indication of prevalence comes from studies on seroprevalence per formed in the United States and Western Europe. In the United States about 15% of women of child-bearing age are seropositive, whilst in Western Europe this figure is about 50%. Tissue cyst of Toxoplasma Humans can pass infection vertically from pregnant mother to fetus but gondii in a cardiac myocyte. Alternatively they could eat animals, for example rodents, harboring tissue cysts. Oocysts shed in cat feces are then a source for human ingestion directly or via an intermediate host. Targets for the host immune response are tachyzoites or bradyzoites, which are extracellular, or intracellular organisms within phagocytes or tis sue cells. On binding to extracellular tachyzoites the antibodies fix complement and cause target lysis. There are other microbicidal and microbistatic mechanisms elaborated by macrophages. To enable these mechanisms macrophages require activation by a type 1 cytokine pattern. However, in the brain, astrocytes and microglial cells serve a phagocytic function and are seen to proliferate during acute infection. In the majority of subjects the immune response brings infection under control without any symptoms. In some cases the local inflammatory response may cause problems in lymph nodes (lymphadenopathy), heart muscle (myocardi tis), skeletal muscle (myositis), and the retina (chorioretinitis). However, in the immunocompromised host, immune surveillance is diminished and bradyzoite reactivation goes unchecked leading to local tissue inflammation. If the infection had been acquired before pregnancy there is the possibility that reactivation of tissue cysts will release tachyzoites during pregnancy. However, an immune response will be present and circulating tachyzoites will be quickly destroyed by antibody and complement, thus preventing any fetal infection. The great est risk of congenital abnormality is with infections between 10 and 24 weeks gestation. Fetal infection at a later stage of infection may not cause any immediate problems.
Individuals who are of the nonsecretor genotype (do not secrete blood group antigens into virus 7zip buy nitrofurantoin online pills. The host secretes defensins from the uroepithelium and Tamm Horsfall protein bacteria zapper for face buy nitrofurantoin 50mg on-line, which binds E antibiotics for uti while trying to conceive buy generic nitrofurantoin 100 mg online. The host develops a normal acquired immune response to the presence of the organism in the upper urinary tract antibiotic kills good bacteria purchase nitrofurantoin australia, with the production of immunoglob ulins of all isotypes antibiotics for persistent uti buy nitrofurantoin overnight delivery. Cell-mediated immunity to infection appears to be of little importance in the urinary tract with the exception of cytokine secretion antibiotic abuse discount nitrofurantoin 100 mg with amex. The high numbers of granulocytes that accumulate in some parts of the renal tract cause damage to the host in a bystander effect through release of oxygen free radicals and proteolytic enzymes antimicrobial infection nitrofurantoin 50 mg online. The role of the adaptive immune response in pyelonephritis is poorly understood antibiotics vs antimicrobial purchase nitrofurantoin without a prescription, although sIgA antibodies are produced and may inhibit the binding of the organism. In neonates the symptoms are nonspecific with vomiting, fever, and a floppy? infant. In cases of pyelonephritis the patient will present with fever, rigors, loin pain, frequency, and dysuria and hematuria. Elderly patients may present with a typical picture or with fever, incontinence, dementia or signs suggestive of a chest infection. A colicky? pain radiating from the loin to the groin is suggestive of renal stones which may occur in the absence of infection, although renal calculi are a risk for infection and often associ ated with Proteus, which has an enzyme (urease) that can hydrolyze urea. Complications include renal scarring, septicemia, papillary necrosis, which if bilateral can lead to renal failure, parenchymal abscess, and perinephric abscess. There is no clear relationship between pyelonephritis and the sequential development of chronic interstitial nephritis and hypertension. The organism can be isolated by culturing a mid-stream specimen of urine (see Figure 1) and in 30% of cases the organism will also be found in the blood culture. Work by Kass showed that if the number of organisms in the urine was greater than 105 bacteria per ml then this correlated well with clinical disease and this figure is considered as a significant? bacteri uria. However, this study was in asymptomatic healthy women and it is recognized that urinary infections can occur with fewer organisms in the urine. Microscopy is generally not useful in the diagnosis of infection, although the presence of white cell casts is suggestive but not diagnostic of pyelonephritis. The differential diagnosis of pyelonephritis depends on the context and age of the patients. Dermatological conditions such as shingles (before the appearance of the rash) and musculoskeletal injury may give rise to loin pain but without urinary symptoms or a fever in the case of musculoskele tal injury. Renal vein thrombosis can give rise to severe pain and fever; renal abscess, papillary necrosis, and urolithiasis will give rise to pain and fever. The presence of a sterile? pyuria can indicate renal tuberculosis, urolithiasis or neoplasm. There is no strong reason for treatment of asymptomatic bacteriuria in either nonpregnant women or the elderly. On the other hand in pregnant women and children, particularly in the latter if there are renal congenital abnormalities allowing vesico-ureteric reflux, then treatment is required even in the absence of symptoms. In cases of pyelonephritis, as there is parenchymal disease, a 2-week course of antibiotics is required, for example cefuroxime or a third-generation cephalosporin, an aminoglycoside or a fluoroquinolone depending on the resistance pattern. How is this disease diagnosed and what is the reflux may infect the renal parenchyma. A significant bacteriuria is a single species in what is the disease pathogenesis? Clin Evid, adults: cost of illness and considerations for the economic eval 2005, 14: 429?440. Staphylococcus saprophyticus is a common cause in producing Enterobacter causing pyelonephritis? Case 11 Giardia lamblia A 24-year-old man went on a 3-month backpacking trip loss of appetite, bloating, and flatulence. He drank bottled water and reportedly ate his stools failed to flush away completely in the toilet and well-cooked food in hotels and restaurants. His doctor requested three stool specimens for return he developed frequent watery, nonbloody diarrhea. Causative agent Giardia was discovered in the 17th century by Anton van Leeuwenhoek examining his own stools by microscopy. This protozoan has two stages to its life cycle (Figure 1): (a) a trophozoite (feeding and pathology-causing stage) that is flagellated (with four pairs of flagellae), pear-shaped, with two nuclei, a ventral sucking? disk, and median bodies. It measures 9?21 mm long by 5?15 mm wide; (b) a cyst, with a highly resistant wall that enables it to remain viable outside the body of the host for long periods. The cyst is smooth-walled and oval in shape, measuring 8?12 mm long by 7?10 mm wide. There are two main genotypes of human infective Giardia isolates, A and B, with other geno types restricted to animals other than humans. Entry into the body Cysts are ingested from contaminated water or food and having passed through the stomach begin to open up at one end (excystation), releasing very short-lived excyzoites, which then divide to become trophozoites (Figure 1). The trophozoites attach to the intestinal wall through their ventral sucking? disk and feed on nutrients (Figure 2). They increase in number by binary fission and colonize large areas of epithelial surface causing diar rhea and damage to the epithelium (see Section 2). Cysts in contaminated water, food, or by the fecal?oral route (hands or fomites) cause infection (2). In the small intestine, the cysts give rise to trophozoites (each cyst producing two trophozoites) (3). The trophozoites multiply by binary fission and remain in the lumen of the small bowel contamination of water, food, or where they can be free in the mucus or hands/fomites with infective cysts attached to the epithelial cells by their ventral sucking disk (4). The passed in stool but cyst is the stage found most commonly in they do not survive in the environment nondiarrheal feces (5). The cysts are infectious when passed in the stool or shortly afterwards and if ingested by 1 another person the cycle begins again. Spread within the body Penetration of the epithelial surface by the trophozoites is very rare, as is migration of the trophozoites to systemic sites. Invasion of the gallbladder, pancreas, and urinary tract have been reported but the trophozoites nor mally remain in the intestine/colon. Spread from person to person Cysts can remain dormant for up to 3 months in cold water. Spread is through ingestion of contaminated food and also via the fecal?oral route (hands and fomites), although water is probably the main source. Sexual transmission of Giardia has been described in attached by means of its ventral sucking homosexual males. Giardia is found in a wide variety of different animal discs to microvilli in the human small species and has been regarded as a zoonosis, although there is little evi intestine. Infection is linked to poor hygiene and sanitation and is more prevalent in warm cli mates. It is more commonly found in children where, in developing coun tries, it is estimated that up to 20% are infected. Giardia is widespread in the United States, with carrier rates as high as 30?60% among children in day-care centers, institutions, and on Native American reservations. Infection is most common between July and October in children younger than 5 years and adults aged 25?39 years. In the Western world, giardiasis is more likely to be diagnosed as a cause of diarrhea that occurs or persists after travel to a developing country. Thus the organism is a cause of traveler?s diarrhea,? also called backpack ers diarrhea? and beavers? fever? (since it was originally believed to be transmitted from beavers to man). In a study of prison volunteers? in the 1950s given the same infectious dose, 50% of subjects developed asymptomatic infections, 35% self-limiting symptomatic infections, and 15% troublesome persistent diarrhea. Given that they received the same dose and strain this illustrates the impact of host susceptibility and resistance. Host defenses Intestinal epithelial cells are shed and replaced every 3?5 days and there fore the trophozoites need to constantly detach and reattach to new epithelial surfaces. The mucus produced by the goblet cells also has some protective effect on attachment of the trophozoites, at least in preventing immediate access. Commensal organisms may also play a role in prevent ing attachment/inhibiting proliferation. Immune responses There appears to be little or no mucosal inflammation in human Giardia infection, which indicates that local defense must be occurring without systemic recruitment. Most of the data on immune responses to Giardia come from experimental animal models. Innate immunity Antimicrobial peptides such as defensins and lactoferrin secreted by intes tinal epithelial cells have anti-giardial activity in vitro and may have activity in vivo. Although monocytes/macrophages can kill trophozoites in vitro by oxidative mechanisms, very few are found in the human intestinal lumen during infection. Patients with hypogammaglobulinemia tend to acquire more chronic giardiasis, suggesting that antibody responses to human Giardia do have some protective role. Murine models of giardiasis show that IgA antibod ies play more of an important role in late infection whilst B-cell-inde pendent mechanisms are important in early stages of infection. Specific IgA antibodies are found in human saliva and breast milk and can protect children against infection in early life. These enzymes have been found to be induced following contact of the parasite with the intes tinal epithelial cells. IgG antibodies to Giardia have been shown to kill Giardia trophozoites in vitro through complement. Although it is unlikely that this mechanism could occur in the intestinal lumen it might be one explanation as to why Giardia does not invade. This antigenic variation (at least in mice) is thought to be a mechanism whereby the trophozoites can avoid the immune sys tem. An alternative, but not mutually exclusive, biological explanation for antigenic variation is their adaptation to different intestinal environments. Pathogenesis the mechanism by which giardiasis causes diarrhea and malabsorption is unclear. Initially it was thought that the attachment of the trophozoites acted as a mechanical barrier to absorption but this is unlikely since the size of the absorptive epithelial area in the intestine is enormous. Interestingly, although more common in animal models of giardiasis, biopsies from only 3% of patients with infection showed villus shortening and there was little inflammation. In experimen tal infection of 10 human volunteers with Giardia type B genotype, only 5 individuals developed symptoms and only 2 of these showed any change to the brush border. Thus microvillus shortening and inflammation are not directly correlated with the symptoms and indeed clearance of the organ ism from the intestinal tract. From in vitro studies there is some evidence for Giardia inducing a change in the cytoskeleton of human duodenal cells with increased apoptosis and disruption of tight junctions in monolayers of intestinal cells. Although disruption of tight junctions has not been con firmed by clinical observation, there is evidence for a correlation of infec tion with impairment of both absorption and digestive functions. Giardia infections can produce symptoms that persist long after infection, although again the mechanisms for this are unclear. The clinical effects of Giardia infection range from asymptomatic carrier status to severe malabsorption (see Section 2). Factors contributing to the variations in presentation include the virulence of particular Giardia strains (see Section 2), their genotype (A or B), the numbers of cysts ingested, the age of the host, and the state of the immune system (see later). If symptoms are present, they occur about 1?3 weeks after ingestion of the parasite. A slower onset may occur with development of yellowish loose, soft and foul-smelling stools often floating due to the high lipid content. Initial symptoms usually last 3?4 days or can become chronic leading to recurrent symptoms, severe malabsorption and debilitation may occur. Children with malabsorption syndrome often show failure to thrive and protein-losing enteropathy can be a complication leading to stunted growth of children, commonly seen in Africa. Reduced uptake of lipids across the gut epithelium causes deficiency in lipid-soluble vitamins, which is an additional problem for children. Poor nutrition can also contribute to an increased risk of a person having symptoms with the infection. Clinical diagnosis is often difficult because the same symptoms can occur with a number of intestinal parasites. Giardiasis is therefore diagnosed by the identification of cysts (Figure 3) or trophozoites (Figure 4) in the feces. Usually three stool samples are taken to determine the presence of the par asite. Three samples are taken as shedding of cysts from infected individ uals is highly variable. After the gelatine dis solves in the stomach the weight carries the string into the duodenum. The string is left for 4?6 hours or overnight while the patient is fasting and then examined for bilious staining. This indicates successful passage into the duodenum and mucus from the string can be examined for trophozoites after fixation and staining. Differential diagnosis Other causes of gastroenteritis need to be considered including amebiasis, bacterial overgrowth syndromes, Crohn ileitis, Cryptosporidium enteritis, irritable bowel syndrome, celiac sprue, and tropical sprue. Management There are several drugs that can be used in the treatment of giardiasis. They include three classes: nitroimidazoles (metronidazole (Flagyl?), tinidazole, ornidazole, and nimorazole); nitrofuran derivatives (furazoli done); acridine compounds (mepacrine and quinacrine). Furazolidone (Furoxone) treatment comprises 100 mg, four times daily for 7 days for adults and 25?50 mg four times daily for 7 days for children. One kind of drug alone has not proven to be effective in all cases, but in situations of resistant infections or recurrent infections, combination drug therapy or single medication given long term can be used. Quinacrine, although used less often than metronidazole because of side effects, has a success rate of about 95%. For exam ple, in Europe mepacrine and furazolidine are not used compared with the Americas. In addition, from a worldwide perspective, albendazole (a benz imidazole compound) is used, which has a much broader range of action Figure 5. In developing countries a single dose albendazole preparation stained with commercially is being given to schoolchildren and has been associated with improved available fluorescent antibodies to Giardia school attendance and educational attainment. They feel better for being and visualized under a fluorescence cleared of protozoa and helminths. Pregnant patients Oocysts of Corynebacterium parvum are Treatment of pregnant patients with Giardia is difficult because of the also seen in this preparation. Mildly symp tomatic women should have their treatment delayed until after delivery. If left untreated, however, adequate nutrition and hydration maintenance is important. Outbreaks of giardiasis in developed countries are often traced back to breakdown in filtration systems of drinking water supplies. What is the causative agent, how does it enter individuals infected with Giardia are often the body and how does it spread a) within the asymptomatic and some are able to clear the body and b) from person to person? Host defenses are not well characterized but a trophozoite and a cyst with a highly resistant wall. There are two main genotypes of human Giardia Commensals may also play a role in preventing isolates, A and B, with other genotypes in attachment/inhibiting proliferation. They lose anti-giardial activity in vitro and may have activity in their cell wall in the duodenum and emerge as vivo. Monocytes/macrophages can kill trophozoites trophozoites, which attach to the intestinal wall in vitro by oxidative mechanisms; very few are found through their ventral sucking? disk and feed. Antibody responses to human Giardia do have infected, up to 25% of their family members also some protective role. Individuals can shed cysts in their human saliva and breast milk can protect children feces and remain symptom-free. The mechanism by which giardiasis causes in children where, in developing countries, it is diarrhea and malabsorption is unclear. There is, however, day-care centers, institutions, and on Native evidence for a correlation of infection with American reservations. Water-borne outbreaks impairment of both absorption and digestive appear to be the most common source of infection. In the Western world, giardiasis is often the cause cytoskeleton of human duodenal cells but the of diarrhea that occurs or persists after travel to a significance of this is unclear. These overgrowth syndromes, Crohn ileitis, include: watery diarrhea with abdominal cramps, Cryptosporidium enteritis, irritable bowel severe flatulence, nausea with or without syndrome, celiac sprue, and tropical sprue. Children with ornidazole, and nimorazole); nitrofuran malabsorption syndrome often show failure to derivatives (e. How is the disease diagnosed and what is the avoidance of contaminated food and water, extra differential diagnosis? No known chemoprophylaxis and no human stool samples are taken to determine the presence vaccine as yet. Which of the following are used for the treatment of True (T) or False (F) for each answer statement, or by giardiasis? Case 12 Helicobacter pylori A 50-year-old advertising executive consulted his primary health-care provider because of tiredness, lethargy, and an abdominal pain centered around the lower end of his sternum, which woke him in the early hours of the morning. His uncle had died of stomach cancer and he was worried that he had the same illness. On examination his doctor noted that he seemed a bit pale and that he had a tachycardia. He was slightly tender in his upper abdomen but there was no guarding or rebound tenderness.
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