Question

Which of the following are source of infection of Toxoplasma:
A. Blood transfusion
B. Organ transplant
C. Green vegetables
D. Arthropods
Choose the correct answer from the options given below:

• A. A, B and D only
• B. B, C and D only
• C. A, B and C only
• D. C and D only

Hint:

To remember Toxoplasma transmission, link the infectious stages to their transmission routes: Oocysts (soil, water, raw vegetables), Bradyzoites (undercooked meat, transplanted organs), and Tachyzoites (transplacental transmission, blood transfusion).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Toxoplasma gondii is a highly successful zoonotic coccidian parasite with a wide host range.
It undergoes sexual reproduction in felids (definitive hosts) and asexual reproduction in warm-blooded animals (intermediate hosts).
Understanding the specific infectious stages (oocysts, tachyzoites, and bradyzoites) and their transmission routes is essential for infection control.

Step 2: Detailed Explanation:
Let us analyze the viability of each option as a source of transmission:
1. Blood transfusion (A):
During the acute stage of infection, rapidly multiplying tachyzoites circulate in the bloodstream (parasitemia).
Transfusion of whole blood or white blood cells from an infected donor in the parasitemic phase can transmit tachyzoites to the recipient.
Therefore, A is correct.
2. Organ transplant (B):
During the chronic stage of infection, Toxoplasma forms tissue cysts containing slow-growing bradyzoites.
These cysts reside permanently in various organs, including the heart, kidneys, and liver.
Transplanting an organ containing these tissue cysts into a seronegative or immunosuppressed recipient can lead to reactivated toxoplasmosis.
Therefore, B is correct.
3. Green vegetables (C):
Infected felids shed millions of unsporulated oocysts in their feces, which sporulate and become infective in the environment.
These oocysts are highly resistant to environmental conditions.
Rainfall and wind can contaminate soil and water, transferring these oocysts onto the surfaces of raw green vegetables.
Ingesting unwashed vegetables is a common route of acquiring oocyst-induced infections.
Therefore, C is correct.
4. Arthropods (D):
Arthropods are not natural hosts or biological vectors for Toxoplasma gondii.
While mechanical transport by flies or cockroaches feeding on cat feces is theoretically possible, they do not serve as a significant source of infection.
Therefore, D is incorrect.
Thus, the sources of infection are A, B, and C.

Step 3: Final Answer:
The sources of infection for Toxoplasma gondii are blood transfusion (A), organ transplantation (B), and contaminated green vegetables (C).
Therefore, the correct answer is option (C).