Enterovirus Enteroviruses top the list of diseases that plague summer swimmers. Most cases are mild, causing cold-like symptoms such as fever, runny nose, and cough and usually people don’t get sick. More serious cases can lead to paralysis and heart or brain infections, but these cases are very rare. Transmission occurs from swallowing contaminated water . Since there is no treatment for this viral illness, the best way to prevent it is to wash your hands often and avoiding those who are infected.