Parvovirus

Question 1

What percentage of women of childbearing age are susceptible to parvovirus infection?

Answer 1

40%

Question 2

What are the risks of fetal loss with parvovirus infection?

Answer 2

<20/40 approximately 11% >20/40 approximately 1%

Question 3

Which women are at increased risk of parvovirus B19 infection in pregnancy?

Answer 3

Women who have never had parvovirus B19 Women who work as teachers or in day cares Women with small children Immunocompromised women

Question 4

What is the pathogenesis of fetal disease with parvovirus B19 virus?

Answer 4

Virus is transmitted trans-placentally. Virus is cytotoxic for rapidly dividing ells and targets erythrocyte progenitor cells- causes haemolytic anaemia and haemolytic arrest. There may also be concurrent hypoalbuminaemia, hepatitis, myocardiits and placentitis. The inflammation and anaemia lead to high output cardiac failure and non-immune hydrops in 0.3-3%

Question 5

With regards to parvovirus B19: IgG positive and IgM negative

Answer 5

Immune- past infection

Question 6

With regards to parvovirus B19: IgG and IgM negative

Answer 6

Not immune- at risk of infection. Repeat testing of IgG in 2-4 weeks if the woman has had an exposure or if symptoms occur

Question 7

With regards to parvovirus B19: IgG negative and IgM positive

Answer 7

May be a recent infection or a false positive IgM. Repeat testing of IgG in 2-4 weeks if the woman has had an exposure or if symptoms occur

Question 8

With regards to parvovirus B19: IgG and IgM positive

Answer 8

Recent infection

Question 9

What fetal surveillance is required in women with proven parvovirus B19 infection in pregnancy?

Answer 9

Anatomy USS between 18-20 weeks. Weekly USS from 4 weeks after seroconversion: looking for signs of hydrops (scalp oedema, ascites, polyhydraminios and cardiomegaly) and measuring MCA PSV