In 10 states throughout the country, 49 people have gotten ill and one has died after an E. coli outbreak at McDonald’s. Infected people reported eating a McDonald’s Quarter Pounder, and experts suspect the beef or the onions on the hamburger sickened folks.
E. coli is often tied to food. The Centers for Disease Control and Prevention (CDC) estimates about 73,000 people are infected by the E. coli strain involved in the McDonald’s outbreak each year in the U.S.
“E. coli is a bacteria that is very, very common. We all have some E. coli in our intestines, and animals have E. coli,” said Dr. James Gaensbauer, an infectious disease specialist at the Mayo Clinic in Minnesota. “So, when we talk about E. coli in the context of these outbreaks, we’re really talking about a particular strain of the bacteria that is more likely to cause disease.”
The one that infected McDonald’s patrons is one of those particular strains that can cause more issues.
“The bacteria is ingested by mouth and most of the time that’s related to foods that have been previously contaminated by the bacteria, but can also be through things like exposure to animals, particularly to cattle, or to other people that are contagious from the E. coli,” as it can spread through fecal-mouth contamination, Gaensbauer explained. “But I think the vast majority comes from eating food that has been contaminated by the bacteria.”
Beef and raw fruit and veggies are common E. coli carriers.
A frequent reservoir for E. coli is the intestines of cattle, Gaensbauer said. “The most common scenario for an outbreak of E. coli is that there’s beef from cattle that had this bacteria that got infected at some point during the meat processing.”
“For the most part, the cattle and different kinds of beef products or other foods or sources that have been contaminated by cow feces are the most common ways to get an infection,” Gaensbauer added.
This bacteria can also spread if fecal matter from cattle contaminates the environment at a farm, like if it spreads to water sources or other items on the farm, Gaensbauer said. This is why raw fruits and veggies are often recalled because of E. coli outbreaks.
Drinking unpasteurized milk and unpasteurized juice can also put you at risk, as can swimming or drinking contaminated water, according to University of California San Francisco Health.
Diarrhea is the most common sign of an E. coli infection.
“We really do worry about the diarrhea as the main problem that the E. coli causes,” said Gaensbauer.
In most cases, E. coli-caused diarrhea is watery and resolves in a few days, but it can also progress to bloody diarrhea, which tends to happen a day or two after the watery diarrhea starts, according to Gaensbauer.
“Anybody who has bloody diarrhea should absolutely be seeking care to get evaluated,” he noted.
If you ingested a potentially contaminated food that is linked to a known outbreak, you should seek care from your physician regardless of whether you have any type of diarrhea, Gaensbauer said. You can check for outbreaks at the CDC’s website.
It’s important that you talk with your doctor about the medications you’re taking, as certain anti-diarrheal meds can make an E. coli infection worse, Gaensbauer noted. Additionally, you want to make sure you stay hydrated if you do have diarrhea.
Some people who ingest E. coli don’t get sick at all. This likely means their immune systems can handle the bacteria, he said.
There is also a rare E. coli complication that you should be aware of, known as hemolytic-uremic syndrome. This causes injury to the kidneys and can be quite severe, particularly in children.
Hemolytic-uremic syndrome “often occurs about a week after the diarrhea has started, and diarrhea may actually have already resolved when this sort of second complication comes up,” Gaensbauer said. Common signs of hemolytic-uremic syndrome include diarrhea and bloody diarrhea, abdominal pain, vomiting, chills and fever, according to the Cleveland Clinic.
For children who have been infected by E. coli, it’s doubly important to work with their doctor to monitor for these symptoms. Overall, children under 5, adults over 65, and folks with weakened immune systems are at most risk of complications from E. coli.
Here’s how you can keep yourself safe.
First step: If there is news of an outbreak, avoid that food item and throw it away if you have it in your home.
“Fortunately, the CDC and the food industry are pretty vigilant, and so, for the most part, when there’s a suspicious food, it gets removed from the market quite efficiently,” Gaensbauer said.
“Beyond that, it’s pretty rare, so it’s not something that people need to be doing some sort of avoidance behavior all the time,” he added.
To stay safe overall, you should make sure you wash your hands after handling raw meat, cook your meat thoroughly (which is 160 degrees for beef, according to the CDC) and use good hand hygiene if you find yourself on a farm or around farm animals, he said. You should also make sure the water you’re drinking is clean and that you thoroughly wash raw fruits and vegetables.
Food safety is a crucial way to keep yourself from getting sick from E. coli, but as in the case of the McDonald’s outbreak, it can be out of your control, too. If you do end up sick after ingesting food or water, communicate with your doctor, who can help you get better.
This article originally appeared on HuffPost.