Christina Applegate says she got sapovirus after eating a contaminated salad. Here's what that is — and how to avoid it.

Christina Applegate at the 29th Annual Screen Actors Guild Awards in 2023 in Los Angeles.
Christina Applegate suffered from a bout of sapovirus, which causes nausea, vomiting and diarrhea. (Gilbert Flores/Variety via Getty Images)

Christina Applegate is getting candid about her recent bout with sapovirus, an infection that causes stomach flu-like symptoms, on her podcast, MeSsy. According to the Dead to Me star, the bug — which she suspects she contracted from a contaminated salad she ordered from a restaurant she’s been going to for 15 years — left her feeling “so dizzy.”

“I was so sick, I couldn’t eat, I couldn’t [do] anything,” she shared in the latest episode of the podcast, in which she and co-host Jamie-Lynn Sigler open up about their experiences living with multiple sclerosis (MS). Applegate, who has spoken previously about wearing adult diapers because MS makes it difficult to “get to the bathroom on time,” also revealed that she woke up in the middle of the night after losing control of her bowels due to the virus.

After a stool test, the actress was diagnosed with sapovirus. Here’s what to know about the virus, and how to avoid getting it.

Sapovirus affects the digestive system and belongs to a similar family of viruses as norovirus, Dr. Ekta Gupta, an associate professor of gastroenterology and hepatology at Johns Hopkins Medicine, tells Yahoo Life, but it’s much less common. About one in 15 Americans will have norovirus in a given year, while sapovirus accounts for about 1% to 17% of diarrhea cases globally, according to a study published in 2017 in Current Opinion in Infectious Disease.

They both cause symptoms including stomach cramps, nausea, diarrhea and vomiting, though vomiting may last longer with sapovirus, a study published in the Journal of Infectious Diseases suggests.

“It spreads by the oral-fecal route,” Gupta says. “It can be spread more commonly in children and infants who are not careful about hand hygiene, so it more commonly spreads in schools and day cares.” But, she adds, people can also contract it after eating something touched by an infected food handler who didn’t wash their hands properly. Or, as Applegate put it: “It is when you ingest the fecal matter of someone else, from your food. Someone else’s poop went into my mouth and I ate it.”

Sapovirus has been linked to oysters, but any food can be contaminated with it. Raw foods, including fruits, vegetables and salads like the one Applegate believes sickened her, are more likely to contain germs, including sapovirus, the Centers for Disease Control and Prevention cautions.

Dr. Christine Lee, a Cleveland Clinic gastroenterologist, says that because bivalves — mussels, oysters and scallops — are the most common source of sapovirus, being careful about consuming these foods is the best step to take. She advises eating these foods only at reputable restaurants known for seafood, since that will mean the food is less likely to be old. But even that’s not foolproof, she says. “A virus can actually live in the water too, so, if you happen to be washing oysters or scallops and some of that water splashed onto your salad, you could get it,” Lee tells Yahoo Life.

She adds that this type of cross-contamination and contamination due to a sick person handling food are both common and hard to detect. Checking for a clean bathroom and dining area can give you some sense of hygiene standards at a restaurant, but not the whole picture, says Lee. She also recommends checking to see if the establishment has been cited for food safety violations.

At home, you can take steps to prevent stomach flu by always washing your hands and produce, keeping your foods separated while preparing them and making sure your foods are properly cooked or refrigerated, according to the CDC.

Applegate found out she had sapovirus after fecal testing. “Usually, people don’t get tested for it unless you’re immunocompromised, because the symptoms can be more debilitating,” says Gupta, who notes that symptoms “may last longer for someone who is immunocompromised,” such as Applegate.

“Any viral infection can cause more serious illness, but [otherwise healthy] individuals don’t need to test, they just need to keep attention on their hydration status and make sure they’re not feeling dizzy or like they’re going to pass out,” Gupta adds.

Like other common stomach viruses, there is no antiviral treatment for sapovirus, Gupta says, so the best thing to do in most cases is simply to rest, drink lots of fluids and wait. If you do become dehydrated enough to feel dizzy or lightheaded, she advises visiting an urgent care clinic to get some intravenous (IV) fluids.