Hand, foot and mouth disease, or HFMD, is a common childhood virus that pediatricians, day care centers and preschools see throughout summer and early fall. It causes fevers, rashes on hands and feet and blisterlike sores in the mouth, which can make drinking and eating extremely uncomfortable. It usually clears up on its own in about a week.
Now, though, the Centers for Disease Control and Prevention (CDC) is reporting that an unusual version has hit the country, with more severe fevers and rashes, some leading to hospitalization for dehydration and pain.
The severe strain was first noticed in Alabama, Connecticut, California and Nevada last winter, which was odd because HFMD typically appears in summer and early fall.
"It's pretty much all over the country at this point," says Steven Oberste, laboratory chief in CDC's viral disease division.
HFMD is usually caused by coxsackievirus A16; the more severe illness is caused by coxsackievirus A6, which has popped up in this country only a few times in the past 40 years, according to the CDC. Both are spread through saliva, mucus, fluid from the blisters and stool.
The CDC has received about 100 to 150 reports of severe cases. "Since there's no required reporting of hand, foot and mouth disease, it's difficult to estimate how many cases are out there," Obereste says. "We have 100 to 150 reports, but clearly it's a lot more than that."
Melissa Arca, a pediatrician in Sacramento, Calif., where the disease seems to have hit hard, says there were times during the summer when she saw three or four children every day with severe HFMD, and she only works half days at her clinic. Researchers don't know if the A6 wave has peaked with the end of summer, so they're unsure whether the new school year will cause a spike in cases. Outbreaks of HFMD occur around the globe, but in recent years they have mostly been in Asia, according to the World Health Organization.