Enterovirus infections often cause no symptoms or mild flu-like symptoms. Though rare, they can lead to serious complications. Children and people with weaker immune systems are most at risk.

Enteroviruses are a group of viruses from the Enterovirus genus. “Entero” means intestine, which is how these viruses enter your body.

According to the Centers for Disease Control and Prevention (CDC), enteroviruses are responsible for about 10 to 15 million infections in the United States each year.

Enterovirus infections do not always cause symptoms. If symptoms occur, they’re usually mild and include:

  • fever
  • runny nose
  • sore throat
  • rash

Babies, children, and teens are much more likely to have symptoms than adults.

Though rare, enteroviruses can cause more serious complications.

Keep reading to learn more about the symptoms and complications of enterovirus and how doctors diagnose and treat them.

There are over 100 types of enteroviruses, which scientists divide into 15 species. Species include:

  • enterovirus A through L, which includes the subspecies:
    • coxsackievirus (CV)
    • poliovirus (PV)
    • echovirus
  • rhinovirus A through C

Each subspecies has several serotypes. Three well-known serotypes are:

  • enterovirus D68 (EV-D68)
  • enterovirus A71 (EV-A71)
  • coxsackievirus A6 (CV-A6)

These are all types of non-polio enteroviruses.

Certain types of enteroviruses are more likely to cause severe symptoms and complications than other types.

Rhinoviruses

Rhinoviruses infect your upper respiratory tract and are the leading cause of the common cold.

Common symptoms of rhinoviruses include:

Rhinoviruses can also cause wheezing and trouble with breathing. They can make breathing more difficult for people with asthma or chronic obstructive pulmonary disease (COPD) and may require hospitalization.

Coxsackieviruses

Coxsackieviruses often do not cause symptoms. If they do, you’ll likely have symptoms similar to the common cold or flu.

But coxsackieviruses, particularly CV-A6 and CV-A16, are known to cause hand, foot, and mouth disease (HFMD). HFMD is more common in children under 5.

Symptoms of HFMD include:

  • blisters or sores in the mouth, which can be painful
  • rash on the hands and feet (usually appears as flat, red spots)
  • fever
  • sore throat
  • headache

Echoviruses

An echovirus infection usually does not cause any symptoms. If you do have symptoms, they’re likely to be similar to those of the cold or flu.

Though rare, an echovirus infection can cause a complication known as viral meningitis. This is an infection of the membranes surrounding the brain and spinal cord.

Viral meningitis can cause the following symptoms:

If meningitis is suspected, the person will require hospitalization for a lumbar puncture and antibiotics until a bacterial cause is ruled out. They are also observed for possible complications.

Polioviruses

Poliovirus, the virus that causes polio, is also a type of enterovirus. Most people with poliovirus infections will not have symptoms. According to the CDC, about 1 in 4 people get flu-like symptoms from poliovirus, including:

  • fever
  • sore throat
  • fatigue
  • headache
  • nausea

The most notable complication of poliovirus is poliomyelitis, or polio for short. Polio causes paralysis, which means you lose the ability to move parts of your body, including the muscles that help you breathe. This occurs in less than 1% of cases.

About 1% to 5% of people with poliovirus will experience meningitis.

Widespread use of the polio vaccine has largely led to the eradication (killing off) of polioviruses in the United States.

Other types of enteroviruses

Two other well-known enteroviruses are enterovirus D68 (EV-D68) and enterovirus A71 (EV-A71).

EV-D68 typically causes mild symptoms like runny nose, sneezing, cough, and body aches. However, in 2014, EV-D68 caused a nationwide outbreak of respiratory illness in the United States. The CDC now monitors it closely.

In rare cases, EV-D68 may also cause a serious neurologic condition called acute flaccid myelitis (AFM) in children.

Symptoms of AFM include:

EV-A71 is well known because it has caused epidemics of HFMD in Southeast Asia. It’s also linked to more severe neurologic diseases, such as meningitis, encephalitis (swelling of the brain and spinal cord), and AFM.

Can enteroviruses affect your brain?

Though rare, enteroviruses can cause inflammation in your brain’s outer layer (meningitis) or tissue (encephalitis). These conditions cause more severe symptoms, like:

  • nausea
  • vomiting
  • stiff neck
  • seizures

Enteroviruses, particularly coxsackieviruses and echoviruses, cause over half of all viral meningitis cases in adults and infants.

Still, very few people with enterovirus infections will develop these brain complications. Most people who get mild viral meningitis or encephalitis from an enterovirus infection recover completely without treatment.

By the time you’re a teen or adult, you’ve probably already had at least one type of enterovirus infection. After your first infection, your body’s immune system can remember the virus and build immunity to it.

This immunity acts as protection, and adults with immunity can usually recover from an enterovirus infection without having any symptoms.

Infants and children, however, may not yet have built up immunity to enteroviruses, so they’re much more likely to experience symptoms.

Common symptoms of enteroviruses in children are similar to those of the common cold. They include:

  • fever
  • sneezing
  • runny or congested nose
  • headache
  • sore throat
  • rash
  • body aches
  • irritability

Severe symptoms are more common in:

  • infants
  • children with weakened immune systems
  • children with respiratory conditions, such as asthma

Most people with enterovirus symptoms recover in 7 to 10 days. However, people with weakened immune systems, asthma, or other respiratory conditions may develop more serious complications and take longer to recover completely.

Are enteroviruses contagious?

Enteroviruses are highly contagious and spread easily from person to person.

You can come in contact with an enterovirus if you:

  • touch a surface that contains the virus before touching your eyes, nose, or mouth
  • share drinks or utensils with someone who has the virus
  • breathe in airborne virus particles
  • come in contact with feces (poop) that contains the virus

Once you have contracted the virus, it can spread to others for several weeks, even if you don’t have symptoms.

Most enterovirus infections don’t cause any complications, and symptoms are mild. Complications are more common in infants or people with weakened immune systems or asthma.

Some enterovirus infections can cause complications such as:

  • viral conjunctivitis (eye infection)
  • HFMD
  • severe respiratory illness
  • viral meningitis (inflammation of the tissues around the spinal cord and brain)
  • viral encephalitis (inflammation of the brain)
  • myocarditis (inflammation of the heart muscle)
  • pericarditis (inflammation of the sac around the heart)
  • AFM
  • sepsis, though this is very rare

Contact a doctor if an infant under 3 months old has a fever of 100.4°F (38°C) or above. Adults and children should be examined by a doctor if their fever is above 103°F (39.4°C) or persists for more than 2 days.

You or your child should also have an appointment with a doctor if you notice any of the following symptoms or if symptoms have not improved after a few days:

  • weakness in the arms or legs
  • difficulty swallowing
  • painful blisters in the mouth
  • wheezing or shortness of breath
  • chest pain
  • severe headache
  • sensitivity to light
  • stiff neck

Most enterovirus infections go away on their own without treatment after a few days. A doctor might recommend over-the-counter treatments to help ease your symptoms and discomfort while you fight the infection. These may include:

  • pain medications, such as acetaminophen for headaches and fever
  • cough drops or lozenges for a sore throat
  • ointments to help soothe blisters or rashes from HFMD

More severe symptoms, such as wheezing or difficulty breathing, might require a visit to the hospital. A doctor might recommend:

  • bronchodilators or nebulizer treatments and oxygen to help you breathe
  • intravenous fluids to prevent dehydration

Some practices may help you prevent enterovirus infections. These can include:

  • washing your hands with warm water and soap often for at least 20 seconds, especially after using the restroom, before eating, and after being out in public and teaching or helping children to do the same
  • teaching children to avoid putting their hands or other objects in or near their mouths
  • cleaning and disinfecting common areas of your home, like the kitchen, bathroom, and living room

Since infants are particularly susceptible to getting enterovirus, it’s best to keep your baby away from people with cold or flu-like symptoms.

If you or your child is experiencing flu-like symptoms, it’s best to stay home from school or work and avoid public areas and contact with others. This can help prevent the transmission of the virus to others.

A vaccine to protect against poliovirus is available. However, vaccines to protect against non-polio enterovirus infections are not yet available.

Enteroviruses mostly cause symptoms in infants and children but can also affect adults.

Symptoms tend to be mild and similar to those of the common cold or flu. In rare cases, the viruses may cause inflammation in the brain or heart, paralysis, or severe respiratory complications.

Contact a doctor if you or your child has flu-like symptoms that don’t go away, get worse over time, or cause symptoms such as:

  • weakness
  • paralysis
  • severe headache
  • chest pain
  • trouble breathing