Apicomplexa Bowel infection Isosporiasis Cryptosporidiosis Sarcosporidiasis Cyclosporiasis Blood & Tissue infection Toxoplasmosis Babesiasis Malaria
Life cycle of sporozoa
Cryptosporidium spp. C.Parvum C.muris C.Baileyi C.Meleagri
Taxonomy of Cryptosporidium Phylum: Apicomplex Sub phylum:sporozoa Class: Sporozoea Subclass: Coccidia Order: Eucoccidia Sub order: Eimeriina Family: Cryptosporidae Genus: Cryptosporidium
Profuse watery diarrhea Pathology Moderate atrophy of intestinal mucosa Enlargment of cyrpts Infiltraion of Mononuclear cells in lamina propia Damage to brush border Malabsorption of fat & CHO
Cryptosporidium parvum oocysts Zeil Nelson staining
Life cycle of sporozoa
CRYPTOSPORIDIUM OOCYSTS
Sarcocystis in the muscle of Mallard
Infective form of cyclospora: When freshly passed in stools, the oocyst is not infective (thus, direct fecal-oral transmission can not occur. Sporulation occur after days or weeks at temperature 22-32 degree
Clinical Features of cyclospora: Average incubation period = 1 week, watery diarrhea, which can be severe. anorexia, weight loss, abdominal pain, nausea and vomiting, myalgias, fatigue low-grade fever,. Untreated infections last for 10-12 weeks
Laboratory Diagnosis of cyclospora: Identification of oocysts in stool specimens by light microscopy. Other methods are also available or under investigation
Specimen processing: fixed in 10% formalin (for direct microscopy, concentration procedures, and preparation of stained smears); fixed in 2.5% potassium dichromate (for sporulation assays and molecular diagnosis);
Treatment: Supportive measures include management of fluid and electrolyte balance, and rest.
Microspora intracellular organism 1-2.5 mic Without mitocondria ribosome similar procaryotes
Causal Agents: Microsporidia, are characterized by the production of resistant spores that vary in size, depending on the species.
coiled inside the spore. The microsporidia spores of species associated with human infection measure from 1 to 4µm and that is a useful diagnostic feature. There are at least 14 microsporidian species that have been identified as human pathogens: Enterocytozoon bieneusi, Encephalitozoon cuniculi, Nosema ocularum, Nosema connori
Life cycle: microsporidia develop by sporogony to mature spores. During sporogony, a thick wall is formed around the spore, which provides resistance to adverse environmental conditions. When the spores increase in number and completely fill the host cell cytoplasm, the cell membrane is disrupted and releases the spores to the surroundings. These free mature spores can infect new cells thus continuing the cycle.
Clinical feature: The clinical manifestations of microsporidiosis are very diverse, varying according to the causal species. diarrhea being the most common.
Encephalitozoon cuniculi: Infection of the GI tract causing diarrhea, and dissemination to ocular, genitourinary and respiratory tracts Acute form in HIV+
Enterocytozoon bieneusi: Diarrhea In HIV+ makes watery diarrhea
Nosema connori: Ocular infection Keratoconjunctivits in HIV+
Infective form: The infective form of microsporidia is the resistant spore and it can survive for a long time in the environment. The spore extrudes its polar tubule and infects the host cell. The spore injects the infective sporoplasm into the eukaryotic host cell through the polar tubule. Inside the cell, the sporoplasm extensive multiplication either by merogony or schizogony (multiple fission). This development can occur either in direct contact with the host cell cytoplasm
Geographic Distribution: Microsporidia are being increasingly recognized as opportunistic infectious agents worldwide. Cases of microsporidiosis have been reported* in developed as well as in developing countries, including: Argentina, Australia, Botswana, Brazil, Canada, Czech Republic, France, Germany, India, Italy, Japan, The Netherlands, New Zealand, Spain, Sri Lanka, Sweden, Switzerland, Thailand, Uganda, United Kingdom, United States of America, and Zambia.
Treatment of microspora: Metronidazole 500 mg 3 times in day
Laboratory Diagnosis: Immunofluorescence assays (IFA) using monoclonal and/or polyclonal antibodies are being developed for the identification of microsporidia in clinical samples. Molecular methods (mainly Polymerase Chain Reaction, PCR) is a very promising technique for the diagnosis of microsporidiosis. PCR is available only in research laboratories and has been successfully used for the diagnosis of Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon hellem, and Encephalitozoon cuniculi. The principal drawback is that it does not work well on formalin-fixed samples stored for long term.