The most common cause of HUS — particularly in children under the age of 5 — is infection with certain strains of E. coli bacteria. E. coli refers to a group of bacteria normally found in the intestines of healthy humans and animals. Most of the hundreds of types of E. coli are normal and harmless. But some strains of E. coli cause diarrhea.
Some of the E.coli strains that cause diarrhea also produce a toxin called Shiga toxin. These strains are called Shiga toxin-producing E. coli, or STEC. When you are infected with a strain of STEC, the Shiga toxin can enter your bloodstream and cause damage to your blood vessels, which may lead to HUS. But most people who are infected with E. coli, even the more dangerous strains, don’t develop HUS.
Other causes of HUS can include:
Other infections, such as infection with pneumococcal bacteria, human immunodeficiency virus (HIV) or influenza
The use of certain medications, especially some of the medications used to treat cancer and some of the medications used to suppress the immune system of organ transplant recipients
Rarely, HUS may occur as a complication of pregnancy or health conditions such as autoimmune disease or cancer
An uncommon type of HUS — known as atypical HUS — can be passed down genetically to children. People who have inherited the mutated gene that causes this form of HUS won’t necessarily develop the condition. But the mutated gene might be activated after exposure to a trigger, such as an infection, the use of certain medications or a chronic health condition.
The majority of HUS cases are caused by infection with certain strains of E. coli bacteria. Exposure to E. coli can occur when you:
Eat contaminated meat or produce
Swim in pools or lakes contaminated with feces
Have close contact with an infected person, such as within a family or at a child care center.
The risk of developing HUS is highest for:
Children 5 years of age or younger
Adults 65 years of age or older
People who have a weakened immune system
People with certain genetic changes that make them more susceptible to HUS
HUS can cause life-threatening complications, including:
Kidney failure, which can be sudden (acute) or develop over time (chronic)
High blood pressure
Stroke or seizures
Clotting problems, which can lead to bleeding
Digestive tract problems, such as problems with the intestines, gallbladder or pancreas
Meat or produce contaminated with E. coli won’t necessarily look, feel or smell bad. To protect against E. coli infection and other foodborne illnesses:
Avoid unpasteurized milk, juice and cider.
Wash hands well before eating and after using the restroom and changing diapers.
Clean utensils and food surfaces often.
Cook meat to an internal temperature of at least 160 degrees Fahrenheit.
Defrost meat in the microwave or refrigerator.
Keep raw foods separate from ready-to-eat foods. Don’t place cooked meat on plates previously contaminated by raw meat.
Store meat below produce in the refrigerator to reduce the risk of liquids such as blood dripping on produce.
Avoid unclean swimming areas. Don’t swim if you have diarrhea.