Here's what Arizonans need to know about the CDC's parvovirus warning

At a time when COVID-19 is at high levels across the U.S., the CDC has issued an alert about another respiratory virus for Americans to be concerned about: human parvovirus B19.

For most people, the Aug. 13 advisory is not cause for alarm, health experts say. People who should be most concerned about human parvovirus are those with underlying blood disorders, including sickle cell disease; people with weakened immune systems and people who are pregnant, according to the CDC (the U.S. Centers for Disease Control and Prevention).

"It's important to be aware of, but for the majority of individuals this is not something that should be of concern," said Dr. Scott Olson, a pediatric infectious disease doctor in Tucson and co-medical director of infectious disease and immunization for the Arizona chapter of the American Academy of Pediatrics.

"It's when you are dealing with the high-risk patients that it's a little more of a concern."

What's important, Olson said, is for people who are either high risk themselves or who live with a high-risk individual to be aware that there is an increased amount of parvovirus circulating in the community and to "take measures to protect themselves and their household members from being exposed."

The CDC advisory says there are "current increases in human parvovirus B19" in the U.S., though it does not specify where and there's no routine testing or surveillance of human parvovirus. CDC officials on Friday did not immediately respond to a question about whether there are regions of the country where the prevalence of the virus appears to be higher. The Arizona Department of Health Services also did not respond to questions about human parvovirus activity in the state.

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Human parvovirus B19 is an illness that pediatricians routinely see in kids, though usually they see it in late winter and in late spring and early summer − not at this time of year. It's also not typically a virus that causes serious complications, Olson said.

"For most children it's a benign viral infection," Olson said. "We know that in kids, it's a fairly common infection and by the time you hit young adulthood about 50% of the population has evidence that they've had the infection. And most of them would never know except for maybe a non-specific illness with maybe a fever and a rash."

The CDC advisory says the public should be aware of human parvovirus symptoms, which have similarities to symptoms of the flu and COVID-19, and also be aware of who is at higher risk. The advisory was based on several indicators, including reports of clusters of parvovirus B19-associated complications among pregnant people and people with sickle cell disease, and an increased prevalence of parvovirus B19 in donated plasma, the advisory says.

"This is interesting timing. We don't usually see it on the tail end of summer. ... This is a little bit late compared to when we usually see it," Olson said. "In clinical medicine, we certainly deal with it fairly frequently but at least in young, healthy individuals, very, very rarely does it cause any complications that would be considered severe."

Here are seven things for Arizonans to know about human parvovirus B19.

It is known by several different names, including 'fifth disease'

Pediatricians refer to the virus by several different names, including "fifth disease," "slapped cheek disease" and "erythema infectiosum."

The "slapped cheek" moniker comes from a characteristic bright red facial rash that may be itchy and typically appears a few days after the fever or flu-like symptoms. It is more common in children than adults, the CDC says, and not everyone gets the rash.

"It's got that biphasic pattern to it, where you get the initial non-specific symptoms of maybe a low grade fever associated with muscle aches, maybe a headache, fatigue and respiratory symptoms and then in the period after that once those symptoms have resolved that is when you get the classic slapped-cheek appearance," Olson said.

Symptoms are similar to COVID-19, common cold

Since human parvovirus B19 is a respiratory infection, the symptoms may appear to be a common cold, COVID-19 or influenza. Like other viruses, some people who contract it will have no symptoms and others may have just mild symptoms.

Most people who develop parvovirus will have a mild cold, and maybe develop a rash, Olson said, and they will typically get better on their own.

"As an infectious disease provider I don't see as many of these cases because the bulk of them, if they even go for care, are going to be managed on an outpatient basis with their pediatrician," Olson said. "It's usually just reassurance and supportive care. Where I get involved is when those individuals are admitted with more serious manifestations and that's going to be in the higher-risk groups."

The telltale signs are:

• Fever
• Headache
• Cough
• Sore throat
• Joint pain
• Rashes (including the characteristic bright red facial rash)

You are no longer contagious once the facial rash appears

Children and adults with parvovirus B19 are no longer contagious once the characteristic facial rash appears, the CDC says.

In addition to the facial rash that's more common in kids, CDC officials say the infection can also cause a general rash on the chest, back, buttocks, or arms and legs that may be itchy. The rash usually goes away in seven to 10 days but can come and go for several weeks and as it starts to go away, it may look lacy, according to the federal agency.

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Infections in pregnant people can cause miscarriages

"Though it's rare, we do know that parvovirus, if it's acquired early in pregnancy, can lead to fetal complications," Olson said.

Treatment for acute infection in pregnant people includes monitoring for and treating severe fetal anemia, CDC officials say.

You can't get it from your dog, or give it to your dog, either

Dogs can get parvovirus, often known as parvo, but it's a different strain.

"Within the parvovirus family there are different serotypes," Olson said. "Parvovirus B19 is the predominant strain in humans and it's not something that is transmitted between canines and humans."

Treatment is 'supportive'

There is no targeted treatment for human parvovirus. The CDC says treatment usually involves relieving symptoms, such as fever, itching, and joint pain and swelling, though for some people it may include blood transfusions and other specialized therapies.

In some people with weakened immune systems, parvovirus can cause chronic or transient aplastic anemia which us typically treated with red blood cell transfusions and intravenous immunoglobulin, according to the CDC.

"It's just supportive care, meaning rest, hydration, acetaminophen or ibuprofen if they are having discomfort or fevers, but for the most part there's no targeted therapy," Olson said. "In large part, that's because most individuals are going to recover from the infection without needing targeted therapy."

Prevention is about 'respiratory etiquette'

"It's spread by respiratory droplets. When you look at control measures, it's the same sort of practices that people are aware of from the COVID pandemic," Olson said. "Basically it amounts to respiratory etiquette, where handwashing, covering your mouth with sneezes or coughs and in an environment at home with someone who is high risk, considering masking during periods of fever and respiratory symptoms."

There is a high rate of human parvovirus transmission within households, Olson said.

With COVID-19 circulating at high levels nationwide, people at high risk may want to wear a mask when they are indoors in public places. Arizona does not appear to be experiencing the same summertime COVID-19 surge as other parts of the country and the world , but with school back in session that could change, local health experts say.

Reach health care reporter Stephanie Innes at Stephanie.Innes@gannett.com or at 480-313-3775. Follow her on X, formerly known as Twitter, @stephanieinnes .

This article originally appeared on Arizona Republic: Here's what Arizonans need to know about the CDC's parvovirus warning