Ovoviviparous parasite which is associated with autoinfection ?
## **Core Concept**
Ovoviviparity is a reproductive strategy where embryos develop inside eggs that are retained within the mother's body until they are ready to hatch. In parasitology, this term is often associated with certain types of helminths. Autoinfection refers to the process where the parasite can complete its life cycle within a single host, leading to a prolonged infection.
## **Why the Correct Answer is Right**
The correct answer, *Enterobius vermicularis* (pinworm), is ovoviviparous and can be associated with autoinfection. However, the classic example of an ovoviviparous parasite with a significant capacity for autoinfection is actually *Strongyloides stercoralis*. This parasite can penetrate the intestinal wall and enter the bloodstream, eventually reaching the lungs, where it breaks through the alveoli and ascends the bronchial tree to the throat, where it is swallowed. It then matures in the intestine. A unique feature of *S. stercoralis* is its ability to autoinfect the host; the filariform larvae can penetrate the intestinal wall or perianal skin, bypassing the need for an external environment to develop, thus completing its life cycle within one host.
## **Why Each Wrong Option is Incorrect**
- **Option A:** While certain species of *Taenia* can have complex life cycles, they are not typically ovoviviparous nor primarily associated with autoinfection in the same way as *Strongyloides*.
- **Option B:** This option might seem plausible but is not specified; however, given the context, it's less likely to be correct compared to the well-known characteristics of *Strongyloides*.
- **Option D:** *Wuchereria bancrofti*, a filarial parasite, causes lymphatic filariasis and does not exhibit ovoviviparity or significant autoinfection in the manner described for *Strongyloides*.
## **Clinical Pearl / High-Yield Fact**
A key clinical point to remember is that *Strongyloides stercoralis* infection can lead to a condition known as hyperinfection syndrome, particularly in immunocompromised patients, where there is an overwhelming increase in the parasite load. This can be life-threatening and is a critical consideration in patients with weakened immune systems.
## **Correct Answer:** .