Which of the following is NOT a route of infection for Toxoplasma gondii?

• A. Direct inoculation with contaminated needles
• B. Ingestion of tissue cysts in undercooked meat
• C. Ingestion of oocysts from cat feces
• D. Transplacental transmission from mother with acute infection

Answer: (A)

Toxoplasma gondii is mainly acquired through oral exposure or vertical transmission. The parasite forms tissue cysts in undercooked meat that you can ingest, and it sheds oocysts in cat feces that contaminate hands, soil, or food. A pregnant person can pass infection to the fetus if the mother acquires toxoplasmosis during pregnancy, which is transplacental transmission. Direct inoculation with contaminated needles is not a typical route of infection because T. gondii is not usually transmitted through puncture wounds or casual skin contact; such a route would require an unusual, contaminated instrument and isn’t how most people encounter the parasite. In rare medical settings, infection can occur via blood transfusion or organ transplantation if the donor is infected, but that’s not the standard exposure scenario. Therefore, direct inoculation with contaminated needles is not a typical route of infection.