Which organism is transmitted to humans by ticks and blood transfusions?

Which organism is transmitted to humans by ticks and blood transfusions?

• A. Babesia
• B. Plasmodium falciparum
• C. Toxoplasma gondii
• D. Leishmania donovani

Answer: (A)

Babesia is a protozoan parasite that infects red blood cells. It is transmitted by Ixodes ticks, the same ticks that spread Lyme disease, and it can also be transmitted through contaminated blood transfusions from an infected donor. This combination—tick-borne transmission and transfusion transmission—is unique among the options and explains why Babesia best fits the scenario. In peripheral blood smears, Babesia appears as intraerythrocytic ring forms, and sometimes the characteristic Maltese cross can be seen, helping distinguish it from other parasites such as Plasmodium species. The other organisms have different principal vectors or transmission routes (for example, malaria is mosquito-borne; Toxoplasma is typically acquired from undercooked meat or cat feces; Leishmania is transmitted by sandflies), which is why they do not match the described transmission pattern.

Babesia is a protozoan parasite that infects red blood cells. It is transmitted by Ixodes ticks, the same ticks that spread Lyme disease, and it can also be transmitted through contaminated blood transfusions from an infected donor. This combination—tick-borne transmission and transfusion transmission—is unique among the options and explains why Babesia best fits the scenario. In peripheral blood smears, Babesia appears as intraerythrocytic ring forms, and sometimes the characteristic Maltese cross can be seen, helping distinguish it from other parasites such as Plasmodium species. The other organisms have different principal vectors or transmission routes (for example, malaria is mosquito-borne; Toxoplasma is typically acquired from undercooked meat or cat feces; Leishmania is transmitted by sandflies), which is why they do not match the described transmission pattern.