25 years old male presented with diarrhea for 6 months. On examination the causative agent was found to be acid fast with 12 micro meter diameter. The most likely agent is aEUR'
Cyclospora [Ref : Harrison 171)* p. 1313, 13141 All the parasites mentioned in the question cause chronic diarrhoea (mostly in immunocompromised patients). All of them reveal oocyst on stool examination. In Giardiasis, parasite is also seen along with oocyst stool examination. Oocyst of all the organisms except giardia are acid fast. The diagnosis rests on the size of the oocyst. DIAGNOSIS OF INTESTINAL PROTOZOAL INFECTION Parasite Stool Fecal acid fast stain Size of the oocyst Giardia Oocyst + Parasite 4 nuclei - 8-12 x 7 x 10 [tm Cryptospo- riclium Oocyst + Small, 4-5 inn in diameter Isospora Oocyst + Large 25 1.tm in diameter Cyclospora Oocyst + Medium 8-101_tm diameter Microsporidia Spores Special fecal stains, tissue biopsies More on this topic Parasites causing chronic diarrhoea Giardia Cryptosporidiosis Isospora Cyclospora Hookworm Amoebiasis Strongyloides Acid fast organisms are ? Mycobacterium Lepra bacilli Nocardia Isospora Bacterial spores Rhodococcus Sinegma bacilli Spermatic head Cryptosporidium Cyclospora
Cryptosporidium
lsospora
Cyclospora
Giardia