Question

Giardia                                                                                           Toxoplasma                                                      Trichomonas

Trypanosoma                                                                         Plasmodium

Case 1:

Two of four campers on a 2-week trip to the mountains of Utah developed diarrhea near the end of their trip. At first, the diarrhea was very watery and foul-smelling. Then it began to alternate with soft stools that looked greasy. The diarrhea was accompanied with abdominal cramps, nausea, flatulence and fatigue. The symptoms persisted in both campers once they returned home, and they sought medical care.
A fecal sample was taken and stained. Although none of the multi-nucleated trophozoites were detected, the samples revealed the presence of egg-shaped cysts about 12 micrometers in length, having 4 nuclei and a median body.
When questioned, the campers stated that near the end of their trip, they drank water from a nearby stream, but only after adding Aquatab Purification Tablets to the water. However, they stated that they had submerged their Ramblers (thermos) into the stream to collect the water before they added the tablets.
Both patients were prescribed Metronidazole (Flagyl) and their symptoms slowly alleviated.

Question 1: What is the Name of Causative Agent, based on the description given in the case?

Question 2: How they got infected by this protozoan?

Answer 1

Q1

Answer: The name of the causative agent is the intestinal parasite called Giardia Lamblia. This causative organism enter the body through the fecal-oral route and leads to occur severe acute diarrhea. The causative organism is localized in the upper portion of the small intestine and excreted alone with the stool.

Q2

Answer: They got infected by this protozoan because of ingestion with contaminated water with the cysts. After ingestion the cyst transform to trophozoite which exhibit active metabolism and become motile. The parasite take up nutrient and undergoes asexual replication. Some trophozoites develops as cysts and do not undergo replication. This cyst passes through the feces. The replicated trophozoite leads to diarrhea.