Which term describes a parasite reinfecting the same host without leaving the body?

Which term describes a parasite reinfecting the same host without leaving the body?

• A. Autoinfection
• B. Zoonosis
• C. Vector-borne
• D. Transovarian

Answer: (A)

Autoinfection describes a parasite reinfecting the same host without leaving the body. In this pattern, the organism completes part of its life cycle inside the host and produces infectious forms that re-enter the host’s tissues or gut, causing a new infection without any external exposure. A classic example is Strongyloides stercoralis, where larvae in the intestine can become infective and penetrate the intestinal lining or perianal skin, establishing a new infection within the same person. This mechanism allows chronic infection and can become severe if the immune system is compromised. Zoonosis involves transmission from animals to humans; vector-borne transmission requires a live intermediary organism like a mosquito; transovarian transmission is vertical transmission through eggs in the vector or parasite, not reinfection within the same host.

Autoinfection describes a parasite reinfecting the same host without leaving the body. In this pattern, the organism completes part of its life cycle inside the host and produces infectious forms that re-enter the host’s tissues or gut, causing a new infection without any external exposure. A classic example is Strongyloides stercoralis, where larvae in the intestine can become infective and penetrate the intestinal lining or perianal skin, establishing a new infection within the same person. This mechanism allows chronic infection and can become severe if the immune system is compromised.

Zoonosis involves transmission from animals to humans; vector-borne transmission requires a live intermediary organism like a mosquito; transovarian transmission is vertical transmission through eggs in the vector or parasite, not reinfection within the same host.