<prompt> Erythema infectiosum is caused by -Parvovirus B19JC virusRotavirusMumps  <response>: Ans. is a i.e., Parvovirus B-19 Parvovirus are non-enveloped DNA ss DNA viruses. Only DNA virus which has single stranded DNA. Smallest virus Has smallest genome Only one medically important human parvovirus - Parvovirus B19 Transmission is by respiratory route and through blood. Infection is commonly acquired in childhood 5-10 yrs. Most of the infections are asymptomatic. Most common presentation is respiratory infection with an erythematous maculopapular rash and arthralgia - Erythema infectiosum or Fifth disease. Starts with prominant erythema of cheeks - slapped cheek disease. Parvovirus B-19 induces aplastic crisis in children with chronic hemolytic anemias, as in sickle cell disease. Parvovirus B-19 infection during second or third trimester of pregnancy may result in nonimmune fetal hydrops. Transplacental transmission rate is 30 or higher. In adults, parvovirus infection commonly causes acute arthralgia and arthritis. Parvovirus B-19 is difficult to grow and virus isolation is not used to detect infection. 