Abby Parks had never heard of parvovirus when she began feeling flu-like symptoms in late April, followed by joint pain and a rash. Parks, 27, a special education teacher in Springfield, Illinois, was about 18 weeks pregnant and had been feeling very sick with a fever for days, but tests for Covid and strep came back negative.
The school nurse, who had been seeing students with “really rosy, red cheeks,” suggested Parks might have the same infection.
“I got progressively sicker,” she said. “I was in bed with a fever for four or five full days.”
When blood tests given by her OB-GYN came back positive for parvovirus B19 in early May, she was referred to a maternal fetal medicine specialist. The doctor discovered the virus had passed to the fetus in utero. The fetus had developed anemia, a very dangerous condition. Doctors gave the fetus a blood transfusion in utero.
We've got the news you need to know to start your day. Sign up for the First & 4Most morning newsletter — delivered to your inbox daily. >Sign up here.
Cases of parvovirus B19 — more commonly known as Fifth disease or “slapped cheek syndrome” because of the red rash that covers an infected patient’s face — are rising in the U.S. On Tuesday, the Centers for Disease Control and Prevention issued an alert to doctors to watch for signs of the highly contagious seasonal virus.
Most of the infections are among children ages 5 to 9, the CDC said. Since March, parvovirus has been circulating in Europe at unusually high rates, according to the European Centre for Disease Prevention and Control.
Most adults have already had the infection as kids and are still protected. However, the CDC warned that pregnant people and people with sickle cell disease who have never been exposed are at risk of serious illness.
U.S. & World
The day's top national and international news.
Parks' doctor, Kathy Bligard, an OB-GYN at Washington University Hospital in St. Louis, said: “Abby is not the only patient whose fetus has needed a blood transfusion in the last few months for parvovirus. It’s certainly something that I used to see maybe once every other year and have seen multiple times in the last few months.”
Bligard said parvovirus is dangerous to pregnant women because it can cross the placenta and infect the fetus and cause it to be anemic, which could lead to fetal death.
Parks has recovered from the virus, but her pregnancy is still at risk.
On Wednesday morning, after an ultrasound showed the fetus wasn’t receiving enough blood from the placenta, Parks was admitted to a hospital in Springfield to care for the baby.
“I do think it was lifesaving for the fetus," Parks said about the earlier transfusion. "Because if that anemia had persisted, with that low blood count, the baby could have died,” Parks said in an interview Wednesday from her hospital bed.
Bligard said the virus makes it harder for a fetus to make new red blood cells. "In order to get oxygen to all of the important organs in our body, our body relies on having those red blood cells. And so it can cause heart failure or even progression to death by having low blood counts.”
Although the disease affects mostly children, when adults do catch it, it can cause more severe symptoms, including joint pain and anemia, which result from problems in creating red blood cells, said Dr. Vincent Iannelli, a pediatrician in the Dallas area. Low red blood cell counts can cause pregnancy complications.
Patients with sickle cell disease are also at high risk.
“Over the past month or two, I think we’ve been seeing more cases,” Iannelli said. Typically Iannelli would see one case of Fifth disease per month; he said he’s now seeing one to two cases per week, noting that the virus is more common in the spring and summer.
What are symptoms of Fifth disease?
In children, Fifth disease is typically mild — its most distinctive symptoms include a fever and respiratory symptoms, followed by a red rash on the cheeks, then a “lacy” rash on the rest of the body, which may be itchy.
The rash appears toward the end of the infection and typically disappears in seven to 10 days, but it may last for several weeks. Importantly, someone with Fifth disease is no longer contagious once the rash appears. “Unfortunately, by the time you know your kid has it, they’re not contagious anymore,” Iannelli said.
The rash can become more pronounced in heat and sunlight, but it doesn't make the infection worse, Iannelli said.
Pregnant women who experience symptoms like joint pain and problems in producing red blood cells should notify their doctors immediately, especially if they know they have been in contact with patients infected with Fifth disease, doctors say.
Iannelli doesn’t believe the rise in cases is cause for alarm.
“Fortunately, most pregnant women had it when they were kids, so they’re immune to it, but every once in a while we do see adults,” he said.
Ultimately, “if you’re healthy, it’s a mild disease," Iannelli said. "If you have immune system problems or if you’re pregnant, early in your pregnancy you should tell your doctor. But for everybody else, it’s basically just a rash.”
He noted that the CDC alert was intended to raise awareness among doctors, not to concern the public.
Why is it called Fifth disease?
In the early 1900s, doctors developed a list of common childhood rashes to help them be more precise in their diagnoses. They identified six major rashes:
- Measles, a highly contagious virus that can cause rash, high fever and respiratory symptoms.
- Scarlet fever, a bacterial infection caused by group A streptococcus.
- Rubella, a viral infection also known as German measles. If someone is exposed during pregnancy, the virus can cause miscarriage or stillbirth. The CDC recommends two doses of the mumps-measles-rubella vaccine for children.
- Filatov-Dukes, no longer considered a distinct disease.
- Fifth Disease, or parvovirus B19, also known as erythema infectiosum.
- Roseola, a viral infection occasionally still called Sixth disease, which can cause high fever and rash.
There are now more recognized childhood rashes, such as chickenpox, so the numbering system isn’t used anymore, except for Fifth disease.
At the hospital, Parks, now at 30 weeks, is being monitored closely. She wants other pregnant women to be aware of the virus and get tested if they have been exposed.
“It has been truly the most difficult experience to go through,” Parks said. “He wasn’t guaranteed to come through the fetal anemia.”
This article first appeared on NBCNews.com. More from NBC News: