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.
Although several pediatricians in the Washington area say they haven’t seen the atypical virus, “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, 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.
Daniel Levy, a pediatrician in Owings Mills, Md., says that he has seen a normal amount of HFMD and the cases don’t seem any more severe than usual. Pediatricians at Children’s National Medical Center and one in Columbia Heights both echoed Levy’s experience.“I have yet to see any child hospitalized or sent to the ER [for HFMD] in my career; it is just not that serious,” Levy says. “It sounds a lot worse than it is.”
The A6 version is odd, for a number of reasons. It causes more severe rashes up the legs, around the mouth and, especially for toddlers, on the buttocks. Arca reports that in some cases, after the rash has gone away, the skin can peel and the fingernails and toenails can fall off. “It’s scary, but they’ll grow back,” she says.
Also, more adults than usual seem to be catching the new strain, according to the CDC. That’s probably because A6 has circulated only sporadically in the United States since 1970, so fewer adults were exposed to it when they were younger, according to Oberste. A6 was big in Japan in the spring and summer of 2011.