Which of the following viruses causes an acute febrile rash and produces disease in immunocompetent children but has been associated with transient aplastic crises in persons with sickle cell disease?
**Core Concept**
Parvovirus B19 is a small, single-stranded DNA virus that primarily infects erythrocyte precursors, causing transient aplastic crises in individuals with sickle cell disease due to its tropism for red blood cell production.
**Why the Correct Answer is Right**
Parvovirus B19 infection leads to the production of IgM antibodies against the virus, which are detectable in the majority of infected individuals. In individuals with sickle cell disease, the virus can cause a transient aplastic crisis by temporarily halting erythropoiesis, leading to severe anemia. This is because the virus infects and lyses erythrocyte precursors, particularly in the marrow of individuals with sickle cell disease, who have a shortened erythrocyte lifespan.
**Why Each Wrong Option is Incorrect**
* **Option A:** Coxsackievirus A16, though a common cause of hand-foot-and-mouth disease, is not typically associated with transient aplastic crises in individuals with sickle cell disease.
* **Option B:** Parainfluenza virus primarily causes respiratory infections and is not linked to erythropoietic suppression.
* **Option D:** Human parvovirus 4, a newly discovered parvovirus, has not been as extensively studied as Parvovirus B19 and is not known to cause transient aplastic crises.
**Clinical Pearl / High-Yield Fact**
Parvovirus B19 infection can be prevented with good hygiene practices and avoidance of close contact with infected individuals. Notably, Parvovirus B19 infection is often asymptomatic in healthy children but can lead to severe disease in individuals with underlying hematological conditions.
**Correct Answer:** C. Parvovirus B19.