Generally, a person with hand, foot, and mouth disease is most contagious during the first week of illness. People can sometimes be contagious for days or weeks after symptoms go away. Some people, especially adults, who get infected with the viruses that cause hand, foot, and mouth disease may not develop any symptoms. However, they may still be contagious. This is why people should always try to maintain good hygiene (e.g. handwashing) so they can minimize their chance of spreading or getting infections.