Question

Miscellaneous protozoans case study:

A group of researchers from a higher education institution (HEI) was tasked to conduct research on the gastro-intestinal (GI) symptoms and diarrhea cases in an indigenous people (IP) community. Upon examination of the tribal community, it was observed that domesticated animals like dogs and cats roamed the IP community in abundance; livestock like pigs, goats, and occasionally cattle, as well as poultry were located in close proximity to the households. In addition, the source of drinking water of the community comes from a cave spring. Interview of the IP community members revealed that no boiling of water was performed prior to intake nor was hand washing a practice in the community. Stool samples were collected during the wet season of June, July, and August, and examined under light microscopy via direct wet mount and iodine mount. There were no trophozoites or cystic stages of amoeba observed. Phyico-chemical analysis of water samples from the cave spring revealed results within limits of the national standard. However, bacteriologic results were failed which indicated high contamination of water samples with fecal coliforms.

Questions to answer:

1) Relative to parasitology, since there were no trophic or cystic stages of amoeba observed from the collected stool samples, what are the most plausible cause of the GI symptoms and diarrhea cases in this IP community? List the top 2 parasitic organisms that should be suspected in this scenario and mention the simplest method in which these suspected organism can be diagnosed under light microscopy.

2) Provide a brief description (1-2 sentences) on the parasitic stage and general morphology (at least 2 descriptions) that can be observed using the method/s you have mentioned above for the respective parasites.

3) Provided the information of the presence of domesticated animals and livestock in close proximity to households. What is the possible parasite of interest specific for pregnant women relative to parasitology (What is the parasite of interest)? Which of the animals is most likely to contribute to the spread of this infection? How can you diagnose this parasite from infected pregnant women (method)?

The answer should be within the parasites enumerated below:

- Balantidium coli

- Isospora belli

- Sarcocystis species

- Cryptosporidium parvum

- Bastocystic hominis

- Cyclospora cayetanensis

- Microsporidia

- Toxoplasma gondii

- Pneumocystis jiroveci