Parvovirus Cases Are on the Rise, CDC Says—8 Symptoms to Know

It feels like 2024 simply won’t let up with health scares, with the onset of bird flu, rising COVID cases, and foodborne illness. Unfortunately, the Centers for Disease Control and Prevention (CDC) is sounding the alarm on yet another troubling trend: an increase in human parvovirus cases. While people who contract the seasonal respiratory virus are often asymptomatic, there are certain signs and symptoms you should keep an eye out for.

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In an Aug. 13 Health Alert Network (HAN) Health Advisory, the CDC noted the increase in parvovirus B19 (also known as fifth disease) in the U.S. There was an earlier uptick in reported cases in 14 European countries.

Roughly 50 percent of adults have detectable parvovirus B19 antibodies (signaling a past infection and presumed protection against reinfection) by the time they’re 20, and more than 70 percent have them by 40. However, new data from the CDC revealed that the proportion of people of all ages with IgM antibodies—which indicate a recent infection—increased between 2022 and 2024. The greatest increase was observed in children between the ages of 5 and 9.

The virus is “highly transmissible in respiratory droplets,” and people working in schools with children are at a higher risk of infection. Some students and staff are infected during school outbreaks, while others are infected after “household exposure.” The illness can also be transmitted from a mother to a fetus during pregnancy or through certain kinds of blood and plasma transfusions. However, the CDC notes that “transfusion-associated parvovirus B19 infection is extremely rare.”

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Those infected with parvovirus B19 might not show any symptoms, but when they do appear, they’re typically mild and appear in two phases. During the first phase, people may experience a fever, myalgia (muscle pain), and general malaise roughly a week after being infected. On its page outlining parvovirus B19, the CDC notes that headache, cough, sore throat, rashes, and joint pain can also occur. People are most contagious during this phase, which typically lasts five days.

During the second phase, adults may have a rash on the trunk of the body and joint pain, while kids often develop a “characteristic facial rash,” also known as a “slapped cheek” appearance. This may also be followed by a net-like rash and joint pain. When the rash shows up, children are no longer contagious.

The CDC notes that people generally only require care during the acute phase and then recover completely. Complications like myocarditis (inflammation of the heart muscle), hepatitis, and encephalitis (inflammation of the brain) are rare. However, those without preexisting immunity to parvovirus B19 who are pregnant, those who have weakened immune systems, and those with a specific form of anemia can have “adverse health outcomes.”

The CDC recommends familiarizing yourself with the symptoms and its respiratory virus guidance, especially if you are at higher risk of severe disease. You should also seek medical care if you are pregnant and have been exposed to parvovirus B19 or show symptoms, as well as if you have an underlying condition and symptoms of the virus.