Astroviruses are a group of viruses that often cause the stomach flu in humans. They most often infect young children, babies, and adults over 65.

Astroviruses are a group of viruses that most often cause viral gastroenteritis, also known as a stomach bug or stomach flu.

Most people who develop gastroenteritis get better without any treatment other than rest and rehydration. However, people with a compromised immune system may develop more severe disease and require hospitalization.

Read on to learn more about astrovirus, infections including typical symptoms, causes, and ways you can prevent infection.

Astroviruses most commonly cause the stomach flu, which is medically known as viral gastroenteritis. Symptoms usually begin 4 to 5 days after you contact the virus and last 1 to 4 days.

Common symptoms include:

Some strains of astrovirus can infect your central nervous system (CNS) or respiratory tract, although these are rare and typically occur in people with compromised immune systems.

Astrovirus is a group of viruses passed between people. There are many subtypes of astroviruses, including:

  • classic HAstV (HAstV1–HAstV8)
  • novel HAstV-MLB (MLB1–MLB3)
  • novel HAstV-VA/HMO (VA1-VA5)

The most common type of astrovirus is the HAstV-1 strain. It most commonly infects infants and young children but can also develop in adults, especially those over the age of 65.

About 90% of children have detectable antibodies to astroviruses by age 5.

Astroviruses are transmitted through the fecal-oral route. This means that the virus is spread from the stool of a person who has it to an unaffected person’s mouth. This might occur due to:

  • eating contaminated food
  • not washing hands after using the bathroom and then touching your or another person’s mouth
  • drinking contaminated water
  • swallowing contaminated water in swimming pools, lakes, or water parks

Stomach flu is one of the most common infectious diseases. Astroviruses are thought to be one of the most common causes of gastroenteritis in babies worldwide. They’re also estimated to account for 2% to 9% of nonbacterial childhood diarrhea.

Astroviruses infections can occur together with other viruses that cause the stomach flu, such as:

Most people with the stomach flu usually heal in a few days without any long-term complications. Some people with severe vomiting or diarrhea may develop dehydration. If this happens, you may need to go to the hospital for rehydration treatment.

People with compromised immune systems might develop CNS infection, which can lead to encephalitis or meningitis.

Most cases of the stomach flu don’t require seeing a doctor.

It’s a good idea to visit a healthcare prpfessional if you:

  • have symptoms of severe dehydration, such as dizziness or passing little urine
  • have bloody diarrhea
  • have sudden or worsening abdominal pain
  • are vomiting constantly with an inability to keep fluids down
  • have blood in your vomit
  • have a fever over 100.4°F (38°C)
  • don’t improve after several days
  • recently returned from a country or area with poor sanitation
  • have a serious underlying health condition like kidney disease

It’s a good idea to get medical attention for your child if they:

  • have symptoms of dehydration, such as passing less urine than usual
  • have blood in their stool or in their vomit
  • vomit consistently or for 24 hours or more
  • have abdominal pain
  • have had diarrhea for more than a week
  • have signs of serious illness, such as a fever over 100.4F, or shortness of breath
  • have serious underlying health conditions like inflammatory bowel disease or a compromised immune system
Handling infants

Infants may need to be treated differently, so contact their doctor as soon as possible if they have the symptoms above.

Your doctor might suspect an astrovirus infection or another form of stomach flu based on your symptoms.

If you have severe symptoms or have a weakened immune system, they might order a stool test, where you provide a sample in a sterile container. This sample is then tested in a lab to find out what type of virus you may have.

Most people with an astrovirus improve without any specific treatment after about 1 to 4 days. Supportive treatments can include:

  • replacing lost fluids and electrolytes with sports drinks, soup broths, or other salty foods
  • over-the-counter medications like loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismal)
  • getting plenty of rest.

Your doctor may prescribe probiotics to help improve your gut microbiome.

You can potentially prevent an astrovirus infection by:

  • washing your hands regularly
  • reminding others in your family to wash their hands regularly
  • getting plenty of rest
  • avoiding swimming in bodies of water marked as polluted
  • avoiding eating seafood you’ve caught yourself if you don’t know whether the water is clean

Is astrovirus contagious?

Astroviruses can be spread between people. They’re primarily transmitted feces-to-mouth through contaminated food or water.

Where is astrovirus most commonly found?

Places astroviruses are commonly found include:

  • contaminated water
  • contaminated food
  • contaminated items and surfaces

What food is astrovirus in?

Astroviruses can be in food contaminated with fecal matter. An example would be sewage-polluted shellfish.

How long are you contagious with astrovirus?

People with the stomach flu might continue to be contagious until 4 to 5 days after their recovery.

Astroviruses are a group of viruses that cause the stomach flu. Symptoms usually pass off in a few days without treatment.

It’s a good idea to get medical help if you or your child develops concerning symptoms like dehydration or persistent diarrhea that doesn’t improve after a few days. In rare cases, you may need emergency treatment for dehydration.