Question

Given below are two statements:
Statement I: Anaemia in case of trypanosomosis mainly occurs as a result of destruction of RBC's due to lashing movement of trypanosomes only.
Statement II: Immunosuppression in trypanosomosis may be due to Polyclonal B-cell activation and mitogenic effect on host cell by trypanosomes.
In light of the above statements, choose the correct answer from the options given below:

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Hint:

Be cautious of statements using restrictive qualifiers like "only".
The pathogenesis of anemia in trypanosomosis involves multiple host immune processes and is far more complex than simple mechanical cell damage by the swimming parasite.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Trypanosomosis is a vector-borne systemic disease of animals characterized by anemia, immunosuppression, fever, and cachexia.
The pathogenesis of these clinical syndromes is highly complex and multifactorial.

Step 2: Detailed Explanation:
Let us review the physiological correctness of each statement:
- Statement I: Anaemia in trypanosomosis is the primary clinical manifestation, but its mechanism is complex.
While physical collision due to parasite motility can cause minor mechanical damage, anemia is mainly caused by extravascular hemolysis (erythrophagocytosis by the mononuclear phagocytic system), immune-mediated lysis (antibody-coated red blood cells), hemodilution, and oxidative stress.
Stating that it occurs *mainly* due to the "lashing movement of trypanosomes only" is physiologically incorrect and represents an outdated concept.
Therefore, Statement I is false.
- Statement II: Immunosuppression is a characteristic feature of chronic trypanosomosis.
It is induced by a variety of parasite-mediated factors, including massive polyclonal B-cell activation, exhaustion of lymphoid organs, hypergammaglobulinemia, and direct mitogenic or suppressive effects of parasite factors on host immune cells.
Therefore, Statement II is true.

Step 3: Final Answer:
Since Statement I is false and Statement II is true, the correct option is (D).