Enteroviruses are viruses that cause some of the most common viral infections. They enter the body through the respiratory or gastrointestinal tract and can easily multiply.

In most cases, people who become infected with an enterovirus do not become ill. Those who do become sick often have relatively mild symptoms similar to those associated with a common cold or the flu. However, some patients, especially infants, may experience more severe illnesses. Between 10 million and 15 million cases of symptomatic enterovirus infections are reported in the United States each year, according to the U.S. Centers for Disease Control and Prevention.

There are two major types of enteroviruses:

• Polioviruses. These viruses can cause poliomyelitis, a condition in which infected nerves cause temporary or permanent paralysis and even death. Polioviruses have been eliminated from the Western Hemisphere.
  
  
• Nonpolio enteroviruses. There are more than 60 nonpolio enteroviruses. They include coxsackie viruses and echoviruses.

People usually become infected with enteroviruses by coming into contact with the respiratory secretions of someone who is infected. Such secretions include saliva, sputum or nasal mucus. The stool of an infected person also can transmit the virus.

In the United States, enterovirus infections are most likely to occur in the summer and autumn. Enteroviruses affect people across all age groups and populations. However, children from infancy to adolescence are at higher risk of infection because they are less likely to have built up antibodies to these viruses.

The nature of the virus itself can be determined through various types of tests, including throat, stool or rectal cultures or from spinal fluid. In most cases, there is no standard treatment for an enterovirus infection. Instead, patients are urged to get plenty of rest and to drink fluids regularly while waiting for the virus to pass from the body.