Viruses

Question 1

What is the most common viral cause of severe watery diarrhea in chidlren in the US - associated with daycare and schools?

Answer 1

Norovirus (type of calicivirus)

Question 2

The following microscopic slide is from a pap smear of a sexually active 22 year old with no significant PMH, no GU/GI complaints, no discharge, no odor, etc. What is the likely etiology of this finding and what is the cell type called seen at the tip of the arrow?

Answer 2

HPV (likely 16 or 18), this is a koilocyte (transformed cell)

Question 3

What is the process by which virions gain new surface proteins during co-infection with another virus (that contains said surface protein), but viral progeny of these virions revert back to the original capsid composition?

Answer 3

Phenotypic mixing

Question 4

A 5 year old presents with a lacy rash on their trunk and a history of low-grade fever, sinus congestion, and headache earlier in the week. A sibling had a similar illness that resolved. In which cells do the infectious agent responsible for this disease replicate?

Answer 4

Parvovirus B19 replicates in RBC progenitors in the marrow because they express blood group P antigen aka globoside, a receptor for the virus.