With infection rates rising in the United States, federal health officials are warning doctors to watch for a respiratory virus called parvovirus B19.
Parvovirus B19 has been around for decades and its symptoms are usually mild or absent in children and healthy adults. However, it can also cause serious complications in humans who are pregnant, have a weakened immune system or suffer from certain blood diseases.
In a health alert issued this week, the Centers for Disease Control and Prevention reported a sharp increase in the proportion of people testing positive for antibodies – indicating a recent infection – particularly among children ages 5 to 9.
This year, health authorities in 14 European countries also reported an unusually high number of cases, according to the CDC.
Infections generally occur in late winter, spring and early summer, with smaller outbreaks occurring every three to four years. This year, the infection is spreading as school starts.
Here’s what you should know about the virus.
How does it spread and how do I know if I am infected?
Parvovirus B19 is transmitted from person to person in three ways: through respiratory droplets, blood, or during pregnancy from mother to fetus. (The canine parvovirus that affects dogs is different from parvovirus B19 and cannot be transmitted from pets to humans or vice versa.)
Most people infected with parvovirus B19 have no symptoms. For those who do have symptoms, these can vary depending on age.
In children, the disease can initially cause flu-like symptoms such as fever, headache and cough. This is when children are most contagious, and according to the CDC, the illness usually lasts for several days. After that, children may develop a facial rash – which is why the disease caused by the virus is also called “slap disease.”
In adults, however, the most common symptom is joint pain, which can last for several days to weeks.
How worried should I be?
Most people recover from the disease on their own without treatment. The risk is that parvovirus B19 invades the bloodstream and causes complications such as a sharp drop in blood counts.
Infection with parvovirus B19 usually has no effect on the pregnancy or the fetus. However, in rare cases, infection can lead to fetal anemia or miscarriage.
The disease can be particularly dangerous for fetuses before 20 weeks, but it can be treated if detected early enough, says Katherine Bligard, a Washington University gynecologist at Barnes-Jewish Hospital in St. Louis who has observed an increase in cases in recent months.
“Fortunately, in the cases I have seen, we have identified the anemia (in the fetus) early enough and treated it with a fetal blood transfusion. All of these fetuses have either already been born or are still doing well in their mother’s womb,” she said.
In some people with weakened immune systems, such as leukemia patients or organ transplant recipients, as well as people with certain blood disorders, such as sickle cell anemia or thalassemia, infection can also lead to severe anemia.
Most adults have some level of immunity. According to the CDC, about 50% of adults in their 20s have detectable antibodies, and more than 70% of adults in their 40s have detectable antibodies.
How do I stay safe?
As with any respiratory virus, the CDC recommends practicing good hygiene, which includes frequent hand washing and cleaning of frequently touched surfaces.
People at high risk should also tell their doctor if they have been in contact with a child who had a high fever and later developed a rash on the face, said Dr. Kawsar Talaat, an infectious disease expert at the Johns Hopkins Bloomberg School of Public Health.
“The most important thing is not to panic. Most of us get this without any problems,” Talaat said. “This is just a note to alert health care providers that they are seeing more infections this summer and to know those who are at higher risk.”
NPR’s Pien Huang contributed reporting.
Copyright: NPR
