Parvovirus B19 and (Fifth Disease)

Last updated: 16 January 2008

What is Parvovirus B19 (Fifth Disease)?

Parvovirus B19 is a common childhood viral illness. It is also called fifth disease, "slapped check" or erythema infectiosum. About 50 per cent of all adults have been infected sometime during childhood or adolescence. People who have had parvovirus B19 are usually immune to it for life. Parvovirus B19 only infects humans and cannot be transmitted to or from animals.

What are the symptoms?

The ill child typically has a "slapped-cheek" rash on the face and a lacy rash on the trunk and limbs. Ocassionally, the rash may itch. An ill child may have a low-grade fever, malaise, or a "cold" a few days before the rash breaks out. The child is usually not very ill, and the rash resolves in 7 to 10 days.

An adult who is infected with parvovirus B19 may have no symptoms at all, or may develop a rash, joint pain or swelling, or both. The joint symptoms usually resolve in a week or two, but can last longer.

How is it spread?

The incubation period varies from 4-20 days from infection to the development of a characteristic rash or other symptoms. The virus is spread by contact with infected respiratory secretions (for example, by coughing), and from mother to unborn baby.

Persons are contagious before the rash develops.

Who is at risk?

Any one who is not immune to it.

What if I am pregnant
Usually there is no serious complication for a pregnant woman or her baby following exposure to a person with parvovirus B19 infection.

• About 50 per cent of women are already immune to parvovirus B19, and these women and their babies are protected from infection and illness.
• Even if a woman is susceptible and gets infected with parvovirus B19, she usually experiences only a mild illness.
• Likewise, her unborn baby usually does not have any problems attributable to parvovirus B19 infection.
• Sometimes, however, parvovirus B19 infection will cause the unborn baby to have severe anemia and the woman may have a miscarriage.
• This occurs in less than five per cent of all pregnant women who are infected with parvovirus B19 and occurs more commonly during the first half of pregnancy.
• There is no evidence that parvovirus B19 infection causes birth defects or mental retardation.
• There is no universally recommended approach to monitor a pregnant woman who has a documented parvovirus B19 infection. Some doctors treat a parvovirus B19 infection in a pregnant woman as a low-risk condition and continue to provide routine prenatal care. Other physicians may increase the frequency of doctor visits and perform blood tests and ultrasound examinations to monitor the health of the unborn baby. The benefit of these tests in this situation, however, is not clear.
• If the unborn baby appears to be ill, there are special diagnostic and treatment options available, and your obstetrician will discuss these options with you and their potential benefits and risks.

How is it prevented?

There is no vaccine or medicine that prevents parvovirus B19 infection.

• Frequent hand washing is recommended as a practical and probably effective method to reduce the spread of parvovirus.
• Excluding persons with fifth disease from work, child care centres, schools, or other settings is not likely to prevent the spread of parvovirus B19, since ill persons are contagious before they develop the rash.
• Pregnant women should not routinely be excluded from a workplace where a parvovirus B19 outbreak is occurring, because of the problems noted above. Whether to stay away from a workplace where there are cases of fifth disease is a personal decision for a woman to make, after discussions with her family, doctor, and employer.

How is it diagnosed?

A doctor can ofetn diagnose parvovirus B19 by seeing the typical rash during a physical examination. In cases in which it is important to confirm the diagnosis, a blood test may be done to look for antibodies to parvovirus. A blod test for parvovirus B19 may show that you are either:

• immune to parvovirus B19 and do not have the infection
• are not immune and could be infected if exposed, or
• have had a recent infection.

How is it treated?

Treatment of symptoms such as fever, pain, or itching is usually all that is needed for parvovirus B19. Adults with joint pain and swelling may need to rest, restrict thier activities, and take medicines such as asprin or ibuprofen to relieve symptoms.

What is the public health response?

Parvovirus B19 infection is not notifiable in New South Wales. Cases are not excluded form childcare, school or work but should be advised to rest at home until they feel better.