Parvovirus B19, erythema infectiosum

General Information

Incubation Period: 4-20 days, generally 7 days.

Signs and Symptoms: Marked redness of cheeks ("slapped-face" appearance) that is often followed in 1-4 days by a red, lace-like rash on the trunk and body. The rash might appear to change or reappear for 1-3 weeks with exposure to sunlight or increases in the environmental temperature, although not all infected persons have a rash. Children may have a slight fever or feel unwell.

It is estimated that about 50% of adults have had a previous infection and are immune. In adults, the rash is often absent, but arthritis lasting for days to months may occur. In 25% of infected adults, the person is asymptomatic (without any symptoms). Immunodeficient persons with infection may experience chronic anemia.

Methods of Transmission: Primarily from direct contact, droplet or airborne spread of respiratory secretions. Rarely by transfusion of blood or blood products. Vertically, from mother to fetus.

Communicable Period: The exact period is unknown, but children are thought to be most infectious before the rash breaks out; the disease is not communicable after the rash appears. Persons with aplastic crisis (absence of normal cell development) are communicable up to one week after the onset of symptoms. Immunosuppressed patients may be infectious for months to years.

Control: EXCLUDE the child with a fever who feels ill. Otherwise, exclusion is not generally practical. Proper handwashing and disposal of tissues can help to reduce transmission.

Other Information

Some pregnant women have miscarried after becoming infected with parvovirus B19. However, the risk of this occurring is relatively low. Pregnant women who subsequently find that they have been in contact with children during the incubation period (4-20 days before signs or symptoms) may want to follow up with their physicians to discuss the option of serological testing to determine their immune status.

Although women who work primarily with children are at increased risk of infection, a routine policy to exclude pregnant women from the workplace when parvovirus B19 is occurring is not recommended. Occupational settings are not the only place where transmission may occur. Prevention methods to avoid infection include proper handwashing, teaching children to cover their mouth when coughing, and disposal of tissues for respiratory secretions.