Fifth disease in a small rural community. What are the consequences?

OBJECTIVE: To characterise the implications of an outbreak of human parvovirus in a small community. METHOD: A community survey was conducted over a period of 18 months in a small rural town in Western Australia with a population of approximately 4300 people. Outbreak cases were assessed by the single general practice in the town. Notification of the survey was placed in both the schools and by advertisement in the local paper. Survey questionnaires distributed to community members were returned on a voluntary basis. After 12 months repeat surveys were sent to all adults who had responded to the initial survey. RESULTS: Eighty-eight definite and 14 equivocal cases were identified as part of the outbreak, which occurred between late July 1994 and February 1995. Serological testing which confirmed human parvovirus B19 infection was available for 29% of cases. The highest attack rate was in the 5-9 year age group. One-third of cases were adults and 9% of them developed symptoms lasting longer than 6 months. Transient anaemia almost certainly due to parvovirus infection was identified in one adult women during the course of the outbreak. No pregnant woman suffered any adverse fetal outcome as a result of human parvovirus infection. CONCLUSION: In an outbreak of parvovirus, children will be most commonly affected although adults can develop polyarthralgia/arthritis which may persist for several months and some may suffer transient anaemia. Pregnant women are potentially at risk of the development of fetal hydrops and fetal death, but advice to them can be based on the estimate of a less than 1% risk of adverse fetal outcome due to parvovirus infection.