An enterovirus infection is caused by any of the viruses in the enterovirus genus, a large group of small RNA viruses responsible for millions of illnesses each year. Most enterovirus infections are mild or produce no symptoms at all, but certain strains can cause serious respiratory illness, meningitis, or a rare form of paralysis, particularly in young children. The genus includes over a dozen species, among them the viruses behind hand, foot, and mouth disease, many summer colds, and historically, polio.
Types of Enteroviruses
Enteroviruses belong to the Picornaviridae family and are divided into 12 species. The most familiar subgroups include coxsackieviruses (A and B), echoviruses, polioviruses, and rhinoviruses (which cause common colds). In everyday medical conversation, though, “enterovirus infection” usually refers to the non-polio enteroviruses, since polio has been eliminated in most of the world through vaccination.
The strains that cause the most concern today are enterovirus A71 (EV-A71), enterovirus D68 (EV-D68), coxsackievirus A16, and echovirus 30. EV-A71 and coxsackievirus A16 are the primary drivers of hand, foot, and mouth disease outbreaks. EV-D68 is notable for causing severe respiratory illness and has been linked to a rare but serious neurological condition called acute flaccid myelitis. Echovirus 30 is one of the most common causes of viral meningitis.
How Enteroviruses Spread
Enteroviruses spread through two main routes: respiratory droplets (coughing, sneezing, close contact) and the fecal-oral route (touching contaminated surfaces, then touching your mouth). This is why outbreaks tend to cluster in daycare centers, schools, and households with young children. The viruses are remarkably tough. They’re non-enveloped, which means they resist many common disinfectants. Ethyl alcohol (60% to 80% concentration) can inactivate most enteroviruses, but isopropyl alcohol, the type in many hand sanitizers, is not effective against them. Soap and water is the more reliable option for hand hygiene.
Seasonal Patterns
In the United States, enterovirus and rhinovirus activity follows a two-peak pattern each year. CDC surveillance data from the 2024-2025 season showed a fall peak in late September 2024, when 30.4% of specimens tested positive, and a smaller spring peak in May 2025 at 22.3%. Even during the lowest-activity weeks, roughly 10% of tested specimens came back positive, meaning enteroviruses circulate year-round at some level.
Symptoms of Enterovirus Infection
Many enterovirus infections cause no symptoms at all. When they do, the illness typically resembles a cold: runny nose, sneezing, cough, and body aches. Some strains cause a distinctive rash on the hands, feet, and inside the mouth (hand, foot, and mouth disease), while others cause sore throat, fever, or a vague “summer flu” feeling. These mild infections usually resolve on their own within a week or so.
More serious presentations include wheezing, difficulty breathing, and pneumonia, especially with EV-D68. Some enteroviruses can infect the lining of the brain and spinal cord, causing viral meningitis (stiff neck, headache, sensitivity to light) or, less commonly, encephalitis. The most alarming complication is acute flaccid myelitis (AFM), a condition where the spinal cord becomes inflamed and limbs become weak or paralyzed.
Acute Flaccid Myelitis
AFM is rare but has drawn significant attention because it primarily affects children and can cause lasting disability. The CDC documented peaks in U.S. AFM cases in 2014, 2016, and 2018, each associated with widespread EV-D68 circulation. In 2018, 92% of children with confirmed AFM had experienced a respiratory or febrile illness before limb weakness set in. Symptoms of AFM include sudden arm or leg weakness, loss of reflexes, difficulty swallowing, slurred speech, facial drooping, and trouble moving the eyes. Upper limb weakness was more common than lower limb weakness, affecting 84% of confirmed cases in 2018.
Since 2019, no confirmed AFM patient has tested positive for EV-D68 specifically, though the virus may simply be circulating at lower levels. Clinicians still watch for AFM in any child who develops sudden limb weakness after a respiratory illness.
Who Is Most at Risk
Young children, especially infants under three months of age, face the highest risk of severe enterovirus disease. While most older children and adults fight off the virus with little trouble, newborns lack the mature immune defenses and specific antibodies needed to contain the infection. Risk factors for dangerous neonatal infections include premature birth, a mother who was sick around the time of delivery, and symptom onset in the first week of life. In these very young infants, enteroviruses can cause hepatitis, inflammation of the heart muscle (myocarditis), and multi-organ failure.
Children with immune deficiencies, particularly those with problems producing antibodies, are also vulnerable to prolonged or severe infections. For healthy older children and adults, the vast majority of enterovirus infections are unremarkable and clear without lasting effects.
How Enterovirus Infections Are Diagnosed
Doctors diagnose enterovirus infections using a molecular test called PCR, which detects the virus’s genetic material. The specimen type depends on the symptoms. For respiratory illness, a nose and throat swab collected within the first week of symptoms works best. Stool samples are also useful because the virus persists in stool longer than in other specimen types. When meningitis or a neurological complication is suspected, a sample of cerebrospinal fluid (collected via spinal tap) is tested. Many routine enterovirus infections are never formally tested because the illness is mild and self-limiting.
Treatment and Recovery
There is no specific antiviral medication for enterovirus infections. Treatment is supportive, meaning it focuses on managing symptoms while the body clears the virus. For mild cases, that means rest, fluids, and over-the-counter options for fever and pain. Children with hand, foot, and mouth disease may need soft foods and cold liquids if mouth sores make eating uncomfortable.
Severe cases, such as those involving breathing difficulty, meningitis, or AFM, require hospital care. Respiratory support ranges from supplemental oxygen to mechanical ventilation depending on severity. AFM recovery varies widely. Some children regain strength over weeks to months, while others have lasting weakness. There is no proven therapy that reverses AFM once it develops, though physical therapy and rehabilitation play a central role in recovery.
Reducing Your Risk
Frequent handwashing with soap and water is the single most effective way to prevent enterovirus spread, especially after changing diapers, using the bathroom, or before preparing food. Alcohol-based hand sanitizers offer some protection, but because enteroviruses lack the outer lipid coating that alcohol dissolves easily, they are harder to kill this way than viruses like the flu. Disinfecting frequently touched surfaces with products containing ethyl alcohol or bleach-based cleaners adds another layer of protection. Avoiding close contact with sick individuals and keeping children with fever or rash home from school or daycare helps limit outbreaks during peak season.