(CNN) -- New York Mets pitcher Noah Syndergaard has been sidelined by hand, foot and mouth disease, a common illness among children but an unusual reason for a baseball player to go on the disabled list. Syndergaard left his Friday start after his pitch velocity dropped.
"It took a toll the other night. He had trouble breathing. He was run down because of the virus, and that's why he had to come out," Mets manager Mickey Callaway said at a news conference. "We're going to continue to monitor him. We're hoping it's just one start and he'll be back."
Hand, foot and mouth disease is an illness commonly seen in children younger than 5. It spreads through contact and attacks exposed adults with fever, sores and skin rash. It's thought Syndergaard contracted the disease during a kids baseball camp he hosted last week.
"Sounds like once the blisters and everything or whatever he's got going on in his hands clears up, he's going to be fine," Callaway said.
In 2016, there was an outbreak at Florida State University, even though the infection is more common in day care centers than on college campuses. However, cases occur with regularity on college campuses, according to the American College Health Association.
Symptoms of hand, foot and mouth disease include fever, painful mouth sores and a rash on the hands and feet.
Hand, foot and mouth is "due to a virus that lives in the intestines, and it is very contagious," said William Schaffner, an infectious diseases specialist at Vanderbilt University. He noted that late summer and early fall are when enteroviruses -- those related to the intestines -- seem to spread readily.
"You are contagious before you are ill and during the illness, but undoubtedly people have the virus in their intestinal tract who never get ill," Schaffner said. There are also people who become infected but don't have symptoms, though they can spread the illness.
How hand, foot and mouth is treated
Hand, foot and mouth disease can be confused with hoof-and-mouth disease, which affects cattle, sheep and swine.
"Humans do not get the animal disease, and animals do not get the human disease," the US Centers for Disease Control and Prevention notes.
"Treatment is comfort measures (pain relief) and hydration," said Dr. Jennifer Shu, an Atlanta pediatrician who sees the disease often in her practice.
"Luckily, most people recover within a week without problems besides some discomfort/pain in the mouth," she said, adding that the disease is "most contagious before the rash appears, so it can be difficult to avoid catching it."
There are many strains of hand, foot and mouth, and some cause distinct illnesses, according to Dr. Mark Pasternack of MassGeneral Hospital for Children.
Outbreaks can easily occur in confined places, so "home, day care, college, the military would all be plausible situations," Pasternack said. With an incubation period of three to five days, it's good to be vigilant about keeping bathrooms, kitchens and other shared spaces clean.
It can be most severe in newborns, Pasternack said. Complications are rare, but if the virus spreads from the intestines to the central nervous system, a patient can get viral meningitis or viral encephalitis, with confusion and seizures and coma. If the spinal cord is affected, there could be motor weakness and difficulty walking, he said.