This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
About parvovirus B19 all are true except: 
Select and explain. 
A. Spread by respiratory route, B. Has affinity for erythrocyte progenitor cells, C. Causes transient aplastic crisis, D. Transplacental transfer occurs in only 10% of cases
D: Transplacental transfer occurs in only 10% of cases
Answer: D: Transplacental transfer occurs in only 10% of cases 
Explanation: Ans. (d) i.e. Transplacental transfer occurs in only 10% of cases. Member of genus erythrovirus, exclusively infects humans Transmission occurs predominantly respiratory route, transfusion related transmission also seen. Pathogenesis - B19 replicates primarily in erythroid progenitors. This specifically is due to limited tissue distribution of B19 receptor, blood groups antigen (globoside). Resulting in transient aplastic crisis. Other cells bearing B-19 receptor include megakaryocytes, endothelial cells, placenta, myocardium and liver. Transplacental infection is seen in 30% and the risk of fetal loss is 9%. Risk of congenital infection is < 1%.