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Non-Polio Enterovirus Infections
What are enteroviruses?
Enteroviruses are small viruses that are made of ribonucleic acid (RNA)
and protein. This group includes the polioviruses, coxsackieviruses, and
echoviruses. In addition to the three different polioviruses, there are 61
non-polio enteroviruses that can cause disease in humans: 23 Coxsackie A
viruses, 6 Coxsackie B viruses, 28 echoviruses, and 4 other enteroviruses.
How common are infections with these viruses?
Non-polio enteroviruses are second only to the "common cold"
viruses, the rhinoviruses, as the most common viral infectious agents in
humans. The enteroviruses cause an estimated 10-15 million or more
symptomatic infections a year in the United States. All three types of
polioviruses have been eliminated from the Western Hemisphere by the
widespread use of vaccines.
Who is at risk of infection and illness from these viruses?
Everyone is at risk. Infants, children, and adolescents are more likely
to be susceptible to infection and illness from these viruses, but adults
can also become infected and ill if they do not have immunity to a
specific enterovirus.
How does someone become infected with one of these viruses?
Enteroviruses can be found in the respiratory secretions (e.g., saliva,
sputum, or nasal mucus) and stool of an infected person. Other persons may
become infected by direct contact with secretions from an infected person
or by contact with contaminated surfaces or objects, such as a drinking
glass or telephone. Parents, teachers, and child care center workers may
also become infected by contamination of the hands with stool from an
infected infant or toddler during diaper changes.
What time of year is someone at risk for infection / illness?
In the United States, infections caused by the enteroviruses are most
likely to occur during the summer and fall.
What illnesses do these viruses cause?
Most people who are infected with an enterovirus have no disease at
all. Infected persons who become ill usually develop either mild upper
respiratory symptoms (a "cold"), a flu-like illness with fever
and muscle aches, or an illness with rash. Less commonly, some persons
have aseptic or viral meningitis. Rarely, a person may develop an illness
that affects the heart (myocarditis) or the brain (encephalitis) or causes
paralysis. Enterovirus infections are suspected to play a role in the
development of juvenile-onset diabetes mellitus (sugar diabetes). Newborns
who become infected with an enterovirus may rarely develop an overwhelming
infection of many organs, including liver and heart, and die from the
infection.
Are there any long-term complications from these illnesses?
Usually, there are no long-term complications from the mild illnesses
or from aseptic meningitis. Some patients who have paralysis or
encephalitis, however, do not fully recover. Persons who develop heart
failure (dilated cardiomyopathy) from myocarditis require longotifiable disease in the United States. Other forms
of meningitis and poliomyelitis are notifiable, which means that any
doctor or laboratory that diagnoses a case must report it to the public
health department.
For further information, please contact the Respiratory and Enteric
Viruses Branch, National Center for Infectious Diseases, at 404-639-3607
(telephone) or 404-639-4960 (facsimile).
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