Infection with this organism during pregnancy can cause congenital hydrocephalus.For the above patient, select the most likely infecting organism.
**Core Concept**
Congenital hydrocephalus refers to the accumulation of cerebrospinal fluid (CSF) in the brain of a fetus, leading to increased intracranial pressure and potential brain damage. This condition can be caused by various factors, including infections during pregnancy.
**Why the Correct Answer is Right**
Toxoplasmosis, caused by the protozoan parasite *Toxoplasma gondii*, is a well-documented cause of congenital hydrocephalus. When a pregnant woman becomes infected with *T. gondii*, the parasite can cross the placenta and infect the fetus, leading to a range of congenital abnormalities, including hydrocephalus. This occurs due to the parasite's ability to infect and damage the choroid plexus, which is responsible for producing CSF.
**Why Each Wrong Option is Incorrect**
* **Option A:** Rubella virus can cause congenital abnormalities, but it is not typically associated with hydrocephalus. Instead, it is more commonly linked to issues such as hearing loss and cataracts.
* **Option B:** Cytomegalovirus (CMV) is another common cause of congenital infection, but it is more often associated with microcephaly (small head size) than hydrocephalus.
* **Option D:** *Listeria monocytogenes* is a bacterium that can cause severe infections in pregnant women, but it is not typically linked to congenital hydrocephalus.
**Clinical Pearl / High-Yield Fact**
Toxoplasmosis is a leading cause of congenital infection worldwide, and pregnant women are at increased risk if they handle cat litter or consume undercooked meat.
**Correct Answer:** C. Toxoplasma gondii