Here’s what you need to know about hepatitis A, the liver-infecting virus that can be spread through contaminated food and water.
Credit: Lars Zahner

If you've ever had food poisoning, it's usually unmistakable. Vomiting, nausea, cramps, and diarrhea can hit without warning, and the symptoms can also resolve just as quickly, vanishing within a day to two (if you're lucky). Although the symptoms and length of time you are sick can vary depending on what germ contaminated your food, there is one bug that isn't exactly like the rest—hepatitis A.

In fact, even though you can get hepatitis A from contaminated food or water, it's isn't strictly considered food poisoning, according to Anthony Michaels, MD, a gastroenterologist at Ohio State’s Wexner Medical Center in Columbus, Ohio. That's because the viruses, parasites, and bacteria that cause food poisoning, such as Salmonella or E. coli, affect the gastrointestinal system, triggering symptoms anywhere from 6 hours to 10 days later. Hepatitis A, on the other hand, is a virus that attacks the liver, and may not cause symptoms for 15 to 50 days (the average is 28 days). And food poisoning tends to pass more quickly than a hepatitis A infection. "The difference is those bacteria don’t lead to liver disease or injury because they’re not directly acting on the liver,” says Dr. Michaels.

Hepatitis A symptoms can be cold-like: fevers, joint aches, nausea, vomiting, and abdominal pain are common, although some people (especially children) have no symptoms at all. "A lot of people don't know they've contracted the disease," says Dr. Michaels. However, a telltale sign you hae hepatitis A is any of the above symptoms coupled with jaundice, or the yellowing of hte skin and eyes, along with dark urine, and pale-colored stools.

Some sources of hepatitis A are raw fruits and vegetables, contaminated water, shellfish, and improperly cooked food. (Outbreaks have been linked to frozen strawberries and raw scallops). The chlorine in the U.S. water supply generally kills the virus, but travel to countries where the virus is common can increase the chance of exposure, as can improper food handling. “If you have someone preparing their food that hasn’t washed their hands and it isn’t cleaned or cooked well, it can put you at risk,” says Dr. Michaels.

A person with hepatitis A is contagious for around two to three weeks after contracting the virus, says Dr. Michaels, and the virus sheds in the person’s stool during this time.

The good news is that unlike other liver-infecting viruses, such as hepatitis B and C, hepatitis A generally doesn't linger in the body or cause a chronic liver infection. The body's immune system generally clears the virus on its own, although it may take weeks or months to recover. After that, most people are immune to future hepatitis A infections.

And there is a vaccine that can prevent hepatitis A in the first place. Experts recommend it for children aged 12 months or older, people traveling to certain countries, and for people at risk because they have other liver diseases. “Getting the hepatitis A vaccine is the best way to prevent the disease and has actually lowered the number of cases in the United States significantly,” says Dr. Michaels.