The Centers for Disease Control and Prevention (CDC) issued a health advisory this week for health care workers and the general public in response to an increase in cases of parvovirus B19.
“During the first quarter of 2024, public health authorities in 14 European countries observed unusually high numbers of parvovirus B19 cases,” the CDC said in its alert. “Recently, CDC has received reports indicating increased parvovirus B19 activity in the United States.”
What you need to know about Contagious We explain what the virus is, how it is transmitted, how it is treated, and who is at high risk.
What is Parvovirus B19?
Parvovirus B19 is a seasonal virus that spreads through respiratory droplets when people cough or sneeze with or without symptoms.
It is called the “fifth disease” because it is part of a group of childhood illnesses that cause a rash, like measles and scarlet fever.
Blood tests can check for the presence of antibodies to parvovirus B19, indicating current or past infection, susceptibility, or immunity.
How does Parvovirus B19 spread?
The virus is highly contagious: According to the CDC, household spread can infect 50% of people, and school spread can infect 20% to 50% of students and staff.
Antibodies from past infection are thought to prevent and protect against future infections, and according to the CDC, by age 20, 50% of adults have these antibodies, and by age 40, that number jumps to 70%.
Parvovirus B19 infection can also be transmitted from mother to fetus during pregnancy or through blood or plasma transfusions, although transfusion-associated parvovirus B19 infection is very rare.
What are the symptoms of Parvovirus B19?
Symptoms of Parvovirus B19 are usually mild and may include:
Fever Headache Cough Sore throat Rash Joint pain
Many people who are infected with parvovirus B19 do not experience any symptoms.
Symptomatic people experience symptoms in two stages. The first stage occurs about a week after infection and includes fever, muscle aches, sore throat, and fatigue. During this stage, which lasts about five days, the amount of virus in saliva and respiratory secretions (an indicator of infectiousness) peaks and the person is most contagious.
During the second stage, about 7 to 10 days after the first stage, children infected with parvovirus B19 often develop a characteristic rash on the face, which may be followed by joint pain and a patchy rash. In healthy adults, the most common symptoms appear during the second stage and include joint pain and a patchy rash on the torso.
Usually, once the rash appears on the face and body, the person is no longer contagious.
How is Parvovirus B19 treated?
There is no vaccine or specific treatment for parvovirus B19.
Most people infected with parvovirus B19 do not require treatment and recover fully. Severe outcomes such as myocarditis, hepatitis, and encephalitis are rare.
Most fetal parvovirus B19 infections during pregnancy resolve without ill effects, but if the mother becomes infected between the 9th and 20th weeks of pregnancy, there is a 5% to 10% risk of fetal anemia or miscarriage.
Treatment of infection in pregnant women includes monitoring and managing severe fetal anemia.
What to do if you think your pet may have Parvovirus B19
In healthy people, parvovirus B19 usually resolves on its own without medical assistance, but the CDC urges people to seek medical care if they are pregnant and have symptoms or have been exposed to someone with suspected or confirmed parvovirus B19.
People with weakened immune systems, including those with chronic hemolytic blood disorders such as sickle cell disease, thalassemia, and hereditary spherocytosis, are also urged to seek medical attention if they experience signs or symptoms of Parvovirus B19.
