Astrovirus

What is astrovirus?

Astrovirus is a common virus that can give you diarrhea. Sometimes people call it a “stomach bug” or “stomach flu,” though it’s not related to influenza.

Astrovirus infections are a form of gastroenteritis. Most cases are mild and don’t last long. They most commonly affect young children, adults over 65 and people with compromised immune systems.

When you look at it under a microscope, astrovirus appears to be shaped like a star. The name astrovirus comes from the Greek word for “star” (pronounced “aster”).

How common is astrovirus?

Astrovirus is very common. Studies suggest that around 90% of kids have had an astrovirus infection by the time they’re 9. Adults are less likely to get sick if they’re exposed to astrovirus because most have immunity (protection from getting sick) from an infection when they were younger.

What are the symptoms of astrovirus?

The main symptom of an astrovirus infection is mild, watery diarrhea. You might also experience:

• Nausea.
• Vomiting.
• Abdominal pain.
• Fever.

Some people may have an astrovirus infection without symptoms.

What’s the incubation period for astrovirus?

The incubation period for astrovirus — how long it takes you to get sick after exposure to the virus — is four to five days.

How do you catch astrovirus?

Astrovirus spreads through the fecal-oral route, which means you get it from accidentally swallowing poop that has the virus in it. You can get astrovirus from:

• Contaminated water. This includes drinking untreated water and swallowing water from lakes, swimming pools, water parks or other recreational water areas.
• Contaminated food. This includes unwashed fruits and vegetables, unpasteurized milk and foods made with unpasteurized milk.
• Contaminated items and surfaces. This includes touching items and surfaces that someone with astrovirus has touched, caring for someone (including children) with astrovirus and changing diapers.

Is astrovirus contagious?

Yes, astrovirus is contagious. There are many ways you can get astrovirus from other people. For example, you can get it from eating food prepared by someone with the infection who didn’t wash their hands after going to the bathroom. If someone in your household has symptoms of astrovirus or another stomach bug, be sure to wash your hands and surfaces thoroughly and keep some distance for a few days.

What are the risk factors for astrovirus?

While anyone can get astrovirus, it’s more common in:

• Kids younger than 5.
• Adults older than 65.
• People with compromised immune systems (from conditions like HIV or certain cancers or from taking immunosuppressant medications).

Because of these risk factors, there can be astrovirus outbreaks at daycare centers and long-term living facilities, where many at-risk people are around each other.

What are the complications of astrovirus?

Complications from astrovirus in adults and kids with healthy immune systems are rare. But if you have a compromised immune system, astrovirus can sometimes infect your central nervous system (brain and spine) and cause encephalitis and meningitis.

How is astrovirus diagnosed?

Healthcare providers typically don’t test for astrovirus, but often diagnose it based on your symptoms or by ruling out other illnesses. If your provider thinks you should get tested (like if your symptoms are severe or you have a compromised immune system), they might perform a stool (poop) test.

For a stool test, your provider will give you a sterile container and instructions on how to get a stool sample. Your provider will send it to a lab, where technicians will look for astrovirus in the sample. Tests they might use include:

• Enzyme immunoassay (EIA) test. This test detects the presence of viral antigens (unique parts of the virus) in stool samples.
• Polymerase chain reaction (PCR) test. This test detects the genetic material of the virus in stool samples.

Both are highly sensitive tests and can detect even low levels of antigens (in the EIA test) or the virus (in the PCR test) in your stool.

How is astrovirus treated?

There aren’t any antiviral medications that treat astrovirus. Most people with healthy immune systems will get better without treatment. Always make sure you or your child is drinking plenty of fluids to keep hydrated anytime you have diarrhea. If your symptoms are severe, your healthcare provider may prescribe oral or IV hydration, or antidiarrheal medications.

If you have an underlying condition that weakens your immune system, your provider will help you manage that condition, which may help you fight off an astrovirus infection.

Can astrovirus infections be prevented?

Washing your hands frequently, especially before eating and after going to the bathroom, is the best way to reduce your risk of astrovirus infection. Hand sanitizers aren’t effective against astrovirus. Other ways to reduce the spread of astrovirus include:

• Not swimming if you have diarrhea. Wait at least two weeks after you stop having diarrhea to swim.
• Avoiding getting water in your mouth if you swim in lakes, rivers or public pools.
• Not drinking untreated water or unpasteurized milk.
• Washing fruits and vegetables with clean water. Wash, peel or cook fruits and vegetables before eating.
• Using bottled water if you’re unsure if drinking or cooking water is clean.
• Teaching kids good handwashing hygiene at a young age.
• Making sure kids wash their hands after going to the bathroom and before eating.

What can I expect if I have astrovirus?

You usually don’t need to have a healthcare provider treat you for astrovirus. You can take care of yourself at home by staying hydrated and keeping an eye on your symptoms. If you have a weakened immune system, your healthcare provider may want to monitor you for worsening symptoms or complications.

How long does astrovirus last?

Astrovirus infections last one to four days in most people.

How do I take care of myself?

Some ways you can take care of yourself with astrovirus include:

• Drinking plenty of fluids and trying to get whatever nutrition you can when you have diarrhea. Water, broth, sports drinks or oral rehydration solutions (like Pedialyte®) can be good choices.
• Avoiding eating or drinking anything that makes diarrhea and dehydration worse, like alcohol and caffeine.
• Over-the-counter medications like loperamide (Imodium®) and bismuth subsalicylate (Pepto-Bismol®, Kaopectate®) can help stop diarrhea, but check with your healthcare provider before taking them. Loperamide can cause heart rhythm problems in high doses. Make sure you tell your provider if you have a heart or liver condition before taking it.

Don’t give medicines to your infant or child without asking their pediatrician first. Some medications that are safe for adults aren’t approved for children.

When should I see a healthcare provider?

See a healthcare provider if your symptoms last longer than a few days or you have large amounts of watery diarrhea (several episodes per day). If you have a compromised immune system, see your healthcare provider right away if you have any symptoms of an infectious disease.

When should I go to the ER?

Go to the nearest emergency room if you can’t keep any food or liquid down, have more than 10 episodes of watery diarrhea in a day, or have symptoms of severe dehydration, including:

• Confusion.
• Weakness or light-headedness.
• Feeling dizzy when you stand.
• Not peeing or barely peeing.
• Dark-colored pee (urine).

What questions should I ask my doctor?

It might be helpful to ask a healthcare provider:

• How can I manage my symptoms at home?
• What medications can I take for my symptoms?
• What should I eat or drink? What should I avoid?
• What’s the best way to keep hydrated?
• What should I do if my symptoms get worse or change?
• What symptoms should prompt me to call you or go to the ER?

A note from Cleveland Clinic

Astrovirus is one of the most common causes of diarrhea in young children. It’s usually mild and resolves on its own in a few days. Drinking plenty of fluids and eating small bites of food can help get you through until you feel better. If you have symptoms that are severe or long-lasting, or if you have a compromised immune system, don’t hesitate to see a healthcare provider.