Hand, foot and mouth disease most commonly infects infants and children under 5. Symptoms include fever, skin rashes and painful blisters in the mouth.
The cause: Viruses from the Enterovirus group, which also includes polioviruses, coxsackieviruses and echoviruses
How you get it: The disease is highly contagious and spread person-to-person by direct contact with the virus, which is found in infected people’s saliva, phlegm or nasal mucus, as well as in their feces and the fluid of blisters. People can catch the virus by touching objects that infected people have touched. Infants and children under 5 are most commonly affected by the disease, so toys and other objects they handle may become sources of infection.
People are most contagious during the first week of illness, but the disease-causing viruses can remain in the body for weeks after symptoms subside. That means infected people can pass the virus even though they may appear healthy.
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The symptoms: Illness begins with fever, malaise and sore throat. Then people develop blister-like sores in the mouth and a skin rash, usually on the palms and soles of feet. Some people who are infected and shedding the virus, including most adults, may have no symptoms.
The treatment: There is no vaccine or treatment for the infection, but over-the-counter medications and numbing mouthwashes can relieve pain and fever. In most cases, the sores resolve themselves as the body fights off the virus. Infected people should take care to practice good hygiene, avoid close contact and make sure dirty surfaces are thoroughly cleaned.
The prognosis: Rarely fatal
Did you know? Hand, foot and mouth disease is not the same as foot-and-mouth disease, which is caused by a different virus and affects livestock like cattle, pigs and sheep. People can’t get the animal disease, and animals can’t get the human disease.
In the most recent outbreak of hand, foot and mouth disease, in March, 30 children in a day-care center in Reno, Nev., were infected. Some of the children’s parents were affected as well.
Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.