Parasitology Practical Questions (total marks 100)

Using the information in the paragraph below you are expected to answer questions
relating to unknown parasite

A. Parasite A is an intracellular organism but can also be found free in the blood and peritoneal
exudate. It can invade a wide array of cells but not red blood cells. Its definitive host is cat.

Mammals and birds are intermediate hosts. Infection can remain in the body for life,
commonly in an inactive form. In immunocompromised individuals, it can reactivate.

Question 1: What is the species name of parasite A? (5 marks)

Question 2: How is parasite A acquired by humans? (5 marks) Questions 3: Draw and label a diagram to show the life cycle of parasite A in definitive and
intermediate hosts (15 marks).

Question 4: Draw and label a diagram to show the rapidly growing form of parasite A. (5
marks).

Question 5: How does the asexual form of parasite A multiply? Draw and label a diagram to
illustrate this. (15 marks).

Question 6: Serologic analysis of a serum sample of a pregnant woman infected with
parasite A can potentially generate one of the results summarised in each row as shown in
Table 1 below. For each row, comment on the clinical relevance of the positive or negative
IgG and IgM result, and add clinical recommendations (20 marks; 5 marks per row).

Table 1: IgM result IgG result Clinical relevance and recommendations
Negative Negative A (write your answer below)
Negative Positive B (write your answer below)
Positive or ambiguous Negative C (write your answer below)
Positive or ambiguous Positive D (write your answer below)
Question 7: Name two serological assays that can generate the results in the Table 1. (5
marks).