opportunistic ad coccidian and microspordial parasites
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Coccidia are microscopic spore-forming, single-celled, obligate intracellular parasites. They must live and reproduce within an animal cell. Coccidia parasites infect the intestinal tracts of animals. Coccidia parasites include:
Toxoplasma gondii
Cryptosporidium parvum, C. hominis**
(C. canis, C. muris, C. felis infections sometimes occur)
Isospora belli
Cyclospora cayetanensis
Sarcocystis hominis
Microsporidia are unicellular, spore-forming. Morphology of spores is useful in distinguishing between different spp. Most spp. are opportunistic parasites. Approximately 10% of the spp. are parasites of vertebrates, including man.
Microsporidia include: Enterocytozoon bieneusi, Encephalitozoon intestinalis.
1. Toxoplasma gondii
Pathogenic: It is pathogenic
Disease: Toxoplasmosis
Acquired: Ingestion of oocysts from
cat faeces, ingestion of raw infected
meat, congenital, transfusion,
transplantation.
Body site: Multiple tissues-
( muscle, brain)
Symptoms: Asymptomatic to severe ( immunocompromised, congenital)
Clinical specimen: Serum, Serologic testing recommended.
Epidemiology: Worldwide
Diagnosis: IgM, IFA, IHA, PCR
Control: Hand washing, proper cooking of meat.
Chemotherapy: Symptomatic infection may be treated with pyrimethamine plus sulphadiazine. Clindamycin and cotrimoxazole can be used.
2. Cryposporidium Spp.
Pathogenic: It is pathogenic
Disease: cryptosporidiosis
Acquired: Faecal-oral transmission,
contaminated food and water.
Body site: Intestine, disseminated
infection in severely compromised
patients.
Symptoms: Nausea, low-grade fever,
abdominal cramps, anorexia, diarrhea.
Clinical Specimen: Stool
Epidemiology: Worldwide, primarily human-
to- human transmission, also animal-to-
animal transmission.
Diagnosis: Microscopy by Giemsa or
modified acid fast technique. EIA methods
are also used.
Control: Improved hygiene, adequate
disposed of faecal waste, water testing,
adequate washing of contaminated fruits and
vegetables.
Chemotherapy: Spiramycin, azithromycin
are sometimes used.
3. Isospora belli:
Pathogenic: It is pathogenic
Disease: Isosporiasis
Acquired: Faecal-oral transmission,
contaminated food and water
Body-site: Intestine
Symptoms: Diarrhea which may
last for months, weight loss,
abdominal colic and fever.
Clinical specimen: Stool
Epidemiology: Worldwide, primarily human-to-human transmission.
Diagnosis: Standard O&P concentration method of fresh sample is recommended . Concentrated Duodenal content can also be examined microscopically for the oocysts or sporocysts.
Control: Improved hygiene, adequate disposal of faecal waste, adequate washing of contaminated fruits and vegetables.
Chemotherapy: Combined pyrimethamine and
sulphadiazine is often used.
Life cycle:
Human
(Intestine)
oocysts
(faeces)
oocysts survive (food, water)
Ingestion of oocyst (person-person)
4. Cyclospora cayetanensis:
Pathogenic: It is pathogenic
Disease: Cyclosporiasis
Acquired: Faecal-oral transmission,
contaminated food and water.
Body-site: Intestine
Symptoms: Nausea, low-grade
fever, fatigue, anorexia
Clinical specimen: Stool
Epidemiology: World wide, human-to-human transmission.
Diagnosis: The organism stain orange with safranin. Acid fast variable. The standard O&P, concentration method is also used.
Control: Improved hygiene, adequate disposal of faecal waste, adequate washing of contaminated fruits and vegetables.
Life cycle: As for Isospora belli
Microsporidia
1. Enterocytozoon bieneusis
Pathogenic: it is pathogenic
Disease: Microsporidiosis
Acquired: Faecal-oral transmission, contaminated food and water
Body-site: Intestine, dissemination can be seen in compromised patients e.g. (HIV infected).
Symptoms: Intractable diarrhea, fever, malaise, weight loss.
Clinical specimen: Stool
Epidemiology: World wide, primarily
human-to-human transmission
Diagnosis: Standard O&P concentration
method is used; modified trichrome
stains is also recommended.
Control: improved hygiene, adequate
disposal of faecal waste, adequate
washing of contaminated fruits and
vegetables.
Microsporidia
2. Encephalitozoon Spp:
Pathogenic: They are pathogenic
Disease: Microsporidiosis
Acquired: Faecal-oral transmission,
contaminated food and water
Body-site: Intestine, dissemination to
kidneys, lower airways, and biliary
tract appears to occur via infected
macrophage.
Symptoms: Intractable diarrhea, fever,
malaise, weight loss.
Clinical specimen: Stool
Epidemiology: Worldwide, primarily human-
to-human transmission
Diagnosis: The Standard O&P
concentration is recommended. Modified
trichrome stains is also recommended.
Control: improved hygiene, adequate
disposal of faecal waste, adequate washing
of contaminated fruits and vegetables.