LES AMIBES INTESTINALES PDF

Resources Causal Agents Several protozoan species in the genus Entamoeba colonize humans, but not all of them are associated with disease. Entamoeba histolytica is well recognized as a pathogenic ameba, associated with intestinal and extraintestinal infections. Other morphologically-identical Entamoeba spp. While the discussed species are morphologically-identical, E. Non-pathogenic amebae e. Endolimax nana, Iodamoeba buetschlii, other Entamoeba species are important because they may be confused with E.

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Resources Causal Agents Several protozoan species in the genus Entamoeba colonize humans, but not all of them are associated with disease. Entamoeba histolytica is well recognized as a pathogenic ameba, associated with intestinal and extraintestinal infections. Other morphologically-identical Entamoeba spp. While the discussed species are morphologically-identical, E. Non-pathogenic amebae e. Endolimax nana, Iodamoeba buetschlii, other Entamoeba species are important because they may be confused with E.

Life Cycle View Larger Cysts and trophozoites are passed in feces. Cysts are typically found in formed stool, whereas trophozoites are typically found in diarrheal stool. Infection with Entamoeba histolytica and E. Exposure to infectious cysts and trophozoites in fecal matter during sexual contact may also occur. Excystation occurs in the small intestine and trophozoites are released, which migrate to the large intestine.

Trophozoites may remain confined to the intestinal lumen A: noninvasive infection with individuals continuing to pass cysts in their stool asymptomatic carriers. Trophozoites can invade the intestinal mucosa B: intestinal disease , or blood vessels, reaching extraintestinal sites such as the liver, brain, and lungs C: extraintestinal disease. Trophozoites multiply by binary fission and produce cysts , and both stages are passed in the feces. Cysts can survive days to weeks in the external environment and remain infectious in the environment due to the protection conferred by their walls.

Trophozoites passed in the stool are rapidly destroyed once outside the body, and if ingested would not survive exposure to the gastric environment. Geographic Distribution Pathogenic Entamoeba species occur worldwide and are frequently recovered from fresh water contaminated with human feces.

The majority of amebiasis cases occur in developing countries. In industrialized countries, risk groups include men who have sex with men, travelers, recent immigrants, immunocompromised persons, and institutionalized populations. Amebic colitis, or invasive intestinal amebiasis, occurs when the mucosa is invaded. Symptoms include severe dysentery and associated complications. Severe chronic infections may lead to further complications such as peritonitis, perforations, and the formation of amebic granulomas ameboma.

Amebic liver abscesses are the most common manifestation of extraintestinal amebiasis. Pleuropulmonary abscess, brain abscess, and necrotic lesions on the perianal skin and genitalia have also been observed.

Figure A: Cyst of E. Notice the chromatoid bodies with blunt, rounded ends arrow. Figure B: Cyst of E. Figure C: Cyst of E. Figure D: Cyst of E. Notice the chromatoid body with blunt, rounded ends arrow. Note the chromatoid body with blunt ends red arrow. Three nuclei are visible in the focal plane black arrows , and the cyst contains a chromatoid body with typically blunted ends red arrow. The chromatoid body in this image is particularly well demonstrated.

Two nuclei are visible in the focal plane black arrows , and the cyst contains a chromatoid body with typically blunted ends red arrow.

Figure A: Immature cyst of E. The specimen was preserved in poly-vinyl alcohol PVA and stained with trichrome. PCR was performed on this specimen to differentiate between E. Image taken at x oil magnification and contributed by the Kansas Department of Health and Environment.

Figure C: Immature cyst of E. The cyst has large vacuoles and the chromatin around the nucleus is clumpy. Figure D: Immature cyst of E.

These cysts range in size from Pathogenic Entamoeba trophozoites have a single nucleus, which have a centrally placed karyosome and uniformly distributed peripheral chromatin. Figure A: Trophozoite of E. Figure B: Trophozoite of E. This typical appearance of the nucleus is not always observed as some trophozoites can have nuclei with an eccentric karyosome and unevenly distributed peripheral chromatin. Figure C: Trophozoite of E. Figure D: Trophozoite of E. The vacuolated cytoplasm seen in this image may be the result of less than optimal preservation.

Figure E: Trophozoite of E. Trophozoites of E. Erythrophagocytosis ingestion of red blood cells by the parasite is classically associated with E. Note that erythrophagocytosis is rarely observed on stained smears. The ingested erythrocytes appear as dark inclusions. The parasite above shows nuclei that have the typical small, centrally located karyosome, and thin, uniform peripheral chromatin. Figure B: Trophozoites of E.

The parasites above show nuclei that have the typical small, centrally located karyosome, and thin, uniform peripheral chromatin. Figure F: Trophozoite of E. Figure A: Numerous E. Arrows indicate examples of trophozoites with visible nuclei. Figure B: Closer view of E. Morphologic differentiation among these is possible, but potentially complicated, based on morphologic characteristics of the cysts and trophozoites.

In culture, differential growth characteristics of E. Historically, differentiation of E. Molecular methods are currently recommended for distinguishing pathogenic Entamoeba species.

Microscopic Detection Microscopic identification of cysts and trophozoites in the stool is the common method for diagnosing pathogenic Entamoeba species.

This can be accomplished using: Fresh stool: wet mounts and permanently stained preparations e. Concentrates from fresh stool: wet mounts, with or without iodine stain, and permanently stained preparations e.

While useful for cysts, concentration methods may not be useful for demonstrating trophozoites. Microscopy also has a low sensitivity if only one stool sample is analyzed, and requires personnel trained in morphological diagnosis. Collection and analysis of three consecutive stool samples within ten days improves the chances for detection.

Also, E. Trophozoites can also be identified in aspirates or biopsy samples obtained during colonoscopy or surgery. Antibody detection is most useful in patients with extraintestinal disease i. Antibody detection is of limited diagnostic value on patients from highly endemic areas that are likely to have prior exposure and seroconversion, but may be of more use on patients from areas where pathogenic Entamoeba spp.

Antigen detection during active infections may be useful as an adjunct to microscopic diagnosis in detecting parasites and can distinguish between pathogenic and nonpathogenic infections. Antibody detection The indirect hemagglutination IHA test has been replaced by commercially available EIA test kits for routine serodiagnosis of amebiasis. Antigen consists of a crude soluble extract of axenically cultured organisms. The EIA test detects antibody specific for E. If antibodies are not detectable in patients with an acute presentation of suspected amebic liver abscess, a second specimen should be drawn days later.

If the second specimen does not show seroconversion, other agents should be considered. Detectable E. Also, patients who have lived in highly endemic areas are likely to be seropositive due to past exposures. Although detection of IgM antibodies specific for E. No commercial antibody detection kits exist for E. Antigen Detection Antigen detection may be useful as an adjunct to microscopic diagnosis in detecting parasites and to distinguish between pathogenic and nonpathogenic infections.

However, utility is limited for frozen or fixed specimens and for post-treatment specimens. Recent studies indicate improved sensitivity and specificity of fecal antigen assays with the use of monoclonal antibodies which can distinguish between E. At least one commercial kit is available which detects only pathogenic E. Some assays also can distinguish E. Comparison of real-time PCR rationales for differential laboratory diagnosis of amebiasis.

J Clin Microbiol ; Laboratory Safety Cysts in unfixed stool samples are potentially infective. Suggested Reading Ali, I. Intestinal amebae. Clinics in Laboratory Medicine, 35 2 , pp. Heredia, R. Entamoeba moshkovskii perspectives of a new agent to be considered in the diagnosis of amebiasis. Acta Tropica, 3 , pp.

ETRADE ROTH IRA APPLICATION PDF

Les dangers de l'amibiase intestinale et - les m├ęthodes de traitement de la maladie

Tauzil Year of fee payment: Your request to send this item has been completed. Method of treating secretory diarrhea with enteric formulations of proanthocyanidin polymer. Preview this item Preview this item. You can move intestinals window by clicking on the headline. Privacy Policy Terms and Conditions. The majority of individuals with ameba infection are asymptomatic, but do pass cysts asymptomatic intraluminal amebiasis This is true for all cases of E.

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Du jamais vu : des amibes cultivent leur nourriture

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