Parvovirus B19 – quick facts:

• Parvovirus B19 causes an infection.
• Most people get it in late winter or early spring.
• Adults with the virus may have pain in their joints.
• The virus can cause cold-like symptoms.
• It primarily affects children and causes a rash on the face, trunk, and limbs.
• AKA fifth disease because it is the fifth of six common childhood illnesses that can cause rashes.
• Infection during pregnancy can lead to complications.
• Patients with sickle cell anemia or similar types of chronic anemia can suffer from acute anemia.

Source and transmission:

The virus is found in respiratory droplets during an infection and is easily transmitted to others through close physical contact. Parvovirus can also be passed from a pregnant woman to her fetus and transmitted through exposure to blood and blood products.

Symptoms of Parvovirus B19:

The majority of people may not know that they have had a parvovirus B19 infection. They do not experience any significant symptoms and once the initial infection resolves, they become immune and will not get the infection again.

Symptoms for many may include flu-like symptoms, such as:

• joint pain and swelling (predominantly in adults)
• fatigue
• a slight fever
• headache
• or an upset stomach

Some severe cases, however, have been tied to chronic arthritis and even to the development of rheumatoid arthritis.

Prevalence in the US:

In the United States, as many as 50% of adults and 85% of the elderly have been infected with parvovirus B19, usually as children or young adults. The infection typically has an incubation period of several days to 2-3 weeks, is active for a short period, and then begins to resolve.

Parvovirus B19 can cause major health problems in three types of patients:

1. People with iron deficiency anemia or a condition that affects or shortens the life of red blood cells (RBCs), such as sickle cell anemia or thalassemia, may develop severe acute anemia during a parvovirus B19 infection. Parvovirus B19 targets cells in the bone marrow that become RBCs and disrupts the production of new RBCs, which can more severely affect those with underlying blood disorders.
2. Women who are infected during pregnancy can pass the infection to their babies. Most fetuses will be fine, but a small percentage will develop severe anemia and a few may have an inflammation and infection of the heart muscle (myocarditis). These conditions can cause miscarriage, congestive heart failure in the fetus, hydrops fetalis (associated with fluid accumulation), and sometimes stillbirth. The greatest risk for fetal complications is during the second trimester of pregnancy.
3. In those with compromised immune systems, a parvovirus B19 infection may cause chronic anemia and be challenging to resolve. This includes people with HIV/AIDS, those who have had organ or bone marrow transplants, and those undergoing chemotherapy treatment for cancer.

When is a Parvovirus B19 test necessary?

Parvovirus B19 testing is not typically used to screen the general population and is not deemed necessary in most cases of infection because symptoms are mild and time-limited. It is usually ordered to determine whether someone is currently, or has recently been, infected with parvovirus only if they are at risk of complications. It may also sometimes be ordered to determine whether someone has ever been exposed to parvovirus.

Result interpretation:

• The presence of IgM class antibodies suggests recent infection.
• The presence of IgG antibodies only is indicative of past exposure.

Sources:

• Parvovirus B19: What You Should Know (https://www.aafp.org/afp/2007/0201/p377.html)
• About Parvovirus B19
  (https://www.cdc.gov/parvovirusb19/about-parvovirus.html)