Virology

A 35-year-old man is bitten by a tick in the northeastern US in late spring. Three weeks later he develops fever and rapidly progressive encephalitis with severe neurologic sequelae. The tick was identified as Ixodes scapularis. The most likely culprit is:

A neonate is born to a mother who had a flu-like illness during pregnancy. The infant has chorioretinitis, hydrocephalus, and intracerebral calcifications. The mother kept a pet hamster during pregnancy. Toxoplasma serology is negative. The most likely cause is:

A college student at a winter conference develops abrupt nausea, projectile vomiting, and watery diarrhea 24 hours after a buffet dinner. Other attendees similarly affected; symptoms resolve in 48 hours. Stool electron microscopy: small, non-enveloped, icosahedral virions. The virus belongs to which family?