Parvovirus B19 or ‘slapped cheek’ illness: All you need to know as cases rise in US

Days after the World Health Organization (WHO) declared the monkeypox (mpox) outbreak a public health emergency of international concern, there is another illness that people need to be wary of as parvovirus B19 or “slapped cheek” or Fifth Disease cases are increasing in the US.

Recently, the US government’s Centers for Disease Control and Prevention (CDC) issued a health advisory to notify healthcare providers, public health authorities, and the public about a surge in human parvovirus B19 activity in America.

Also, in the first quarter of 2024, public health authorities in 14 European countries observed unusually high numbers of cases of parvovirus B19, as per CDC's advisory.

What is parvovirus B19 or ‘slapped cheek’ illness?

According to the CDC’s health advisory, parvovirus B19 is a seasonal respiratory virus that is transmitted through respiratory droplets by people with symptomatic or asymptomatic infection.

Parvovirus B19 is “highly transmissible in respiratory droplets”, with 50 per cent of susceptible people infected after household exposure and 20 to 50 per cent of susceptible students and staff infected during school outbreaks, it said.

Historically, people working in schools and in close contact with children (e.g., daycare workers and teachers) have had high occupational risk of infection. About 50 per cent of adults have detectable antibodies by age 20 years. More than 70 per cent of adults have detectable antibodies by age 40 years. Antibodies from prior infection are thought to protect against reinfection.

Parvovirus B19 infection can be transmitted during pregnancy (i.e., from mother to the foetus) or through transfusion of blood components and certain plasma derivates.

People with IgM antibodies

The proportion of people with IgM antibodies, an indicator of recent infection, increased among all ages from less than three per cent during 2022-2024 to 10 per cent in June 2024 in the US.

The “greatest increase”, CDC said, was observed among children aged 5-9 years, from 15 per cent during 2022-2024 to 40 per cent in June 2024. Among plasma donors, the prevalence of pooled samples with parvovirus B19 DNA less than 104 IU/mL increased from 1.5 per cent in December 2023 to 19.9 per cent in June 2024.

Parvovirus B19 infection is usually mild in people who are otherwise healthy. Common symptoms include “slapped cheek” rash in children, and joint pains in adults.

“In individuals with blood disorders or a weakened immune system, infection can cause a low blood count. Infection during pregnancy can sometimes lead to additional complications,” CDC said.

Some people who are infected with virus show no symptoms and when symptoms occur they are mild and include fever, headache, cough, sore throat, rashes and joint pain.

The CDC stated that the clinical presentation most often associated with parvovirus B19 infection is a red rash on the face, also called a “slapped cheek” rash. This rash typically appears a few days after the fever or flu-like symptoms. It is more common in children than adults.

Parvovirus B19 infection can also cause a general rash on the chest, back, buttocks, or arms and legs. The rash may be itchy. It usually goes away in 7 to 10 days but can come and go for several weeks. As it starts to go away, it may look lacy, it added.

Treatment

According to CDC, parvovirus B19 infections are usually mild and will go away on their own. Children and adults who are otherwise healthy usually recover completely. Treatment usually involves relieving symptoms, such as fever, itching, and joint pain and swelling. For persons who develop a low blood count, treatment may include supportive care, blood products, and other specialized therapies.

Parvovirus B19 infection prevention and vaccine

According to experts in the US, there is no vaccine or treatment that can prevent parvovirus B19 infection.

However, to prevent the spread of parvovirus B19, they recommend practising good hygiene, covering your mouth and nose with a tissue when you cough or sneeze.

“Learn and use proper handwashing techniques. Frequent handwashing is especially important in childcare settings and healthcare facilities. Clean frequently touched surfaces, such as countertops, handrails, and doorknobs, regularly, and take steps for cleaner air,” they recommend.

Any parvovirus cases in India?

So far, not a single case of parvovirus B19 has been reported among humans in India. However, in 2023, a parvovirus outbreak was reported among dogs in Lucknow.