A 7-year-old girl is brought to the office due to a diffuse rash. The father says she developed a lace-like, erythematous rash this morning on her stomach, back, and extremities. Two days ago, the girl developed red, flushed cheeks. She also had congestion, headache, and a low-grade fever for 3 days earlier this week. Last week, her younger brother had similar symptoms that resolved spontaneously. The infectious agent most likely responsible for this patient's disease replicates in progenitors of which of the following cell lines?

Question

A 7-year-old girl is brought to the office due to a diffuse rash.  The father says she developed a lace-like, erythematous rash this morning on her stomach, back, and extremities.  Two days ago, the girl developed red, flushed cheeks.  She also had congestion, headache, and a low-grade fever for 3 days earlier this week.  Last week, her younger brother had similar symptoms that resolved spontaneously.  The infectious agent most likely responsible for this patient's disease replicates in progenitors of which of the following cell lines?

Quizplus · Accepted Answer

11ec160b_3876_703f_9249_cfa1dba11926_MD0001_00 Erythema infectiosum, or fifth disease, is a benign childhood illness caused by parvovirus B19, a single-stranded DNA virus. After a 1-2 week incubation period, a nonspecific prodrome (eg, malaise, congestion, headache, fever) is followed by an erythematous rash on the cheeks. This "slapped-cheek" rash, as shown in the image above, usually spares the nasolabial folds and develops after the initial symptoms have resolved. A lacy, reticular rash then follows, spreading over the trunk and extremities. The rash may result from immune complex deposition, the timing of which coincides with increasing levels of serum virus-specific IgM and IgG. Parvovirus B19 replicates in erythrocyte precursors in the bone marrow. These cells express blood group P antigen (also known as globoside), which is the cellular receptor for parvovirus B19. Viral replication in the nucleus leads to cell lysis (ie, decreased reticulocytes and red blood cells). Acute and chronic sequelae of parvovirus B19 infection can occur in specific populations (eg, chronic anemia in immunosuppressed patients, aplastic crisis in those with underlying hematologic abnormalities such as sickle cell disease). (Choice B) Hepatitis A-E viruses replicate within mature hepatocytes and cause inflammation and cell necrosis. Hepatitis B and C are chronic infections and the most common causes of cirrhosis and liver cancer. (Choice C) Rotavirus replicates in fully differentiated intestinal epithelial cells. The infected and damaged enterocytes slough into the intestinal lumen, leading to profuse watery diarrhea. (Choice D) Mature lymphocytes are a common site of viral replication (eg, human herpesvirus-6 [HHV-6], HIV). HHV-6 causes roseola infantum, which presents as high fever followed by a diffuse maculopapular rash in children age <2. (Choice E) Many common viruses (eg, influenza, parainfluenza, rhinovirus) replicate within respiratory epithelial cells (but not their precursors). Parainfluenza replication, for example, can be localized to only nasal and pharyngeal epithelium (eg, rhinorrhea, sore throat) or can spread more extensively, causing laryngotracheitis (croup), bronchiolitis, or pneumonia. Educational objective: Erythema infectiosum (fifth disease) is caused by parvovirus B19 and presents with a nonspecific prodrome (eg, malaise, fever, congestion) followed by a classic "slapped-cheek" facial rash and a lacy, reticular body rash. Parvovirus is highly tropic for erythroid precursor cells and replicates predominantly in the bone marrow. __________ References: Parvovirus B19 Replication and Expression in Differentiating Erythroid Progenitor Cells. (http://www.ncbi.nlm.nih.gov/pubmed/26845771)

A 7-Year-Old Girl Is Brought to the Office Due to a Diffuse