MSU Extension

Escherichia Coli, more commonly abbreviated as E. coli, is a bacteria found in the intestinal tract of healthy humans and animals. According to the Centers for Disease Control and Prevention (CDC), approximately 265,000 E. coli infections occur each year in the United States. Of these infections, 36 percent are caused by the O157:H7 E. coli strain. This strain of E. coli is also more likely to cause severe illness, bloody diarrhea, and potentially, hemolytic uremic syndrome (HUS), which is a type of kidney failure.

Although there are many strains of E. coli, E. coli O157:H7 is the one most often referred to in the news when an outbreak is reported and will be the strain referenced when using ‘E. coli’ in this article. The E. coli O157:H7 strain causes disease by making a toxin called Shiga toxin and may also be recognized by its longer name of “Shiga toxin-producing” E. coli.

How do you catch it?

Human E. coli infection is typically caused when tiny amounts of human or animal feces get in the mouth and are subsequently swallowed. The E. coli incubation period is 1-10 days and only 10 cells are necessary to cause infection, according to the Food & Drug Administration (FDA). Although cattle are the most common origin of E.coli infection, the World Health Organization (WHO) states that animals such as sheep, goats, pigs, horses, deer, dogs, cats and birds can also be infected. Locations such as petting zoos, farms where people have access to animals, and even campgrounds where cattle have previously grazed have been sources of E. coli infection.

Contaminated food or water is the source of most human E. coli infections and common food culprits include undercooked ground beef, raw milk, cold sandwiches, water, unpasteurized apple juice, sprouts, and vegetables, according to the FDA. Additionally, swimming in contaminated water or pools can also lead to E. coli infection by ingesting or swallowing water droplets. Aside from contaminated food and water and animal-to-person contact, E. coli can also be spread through person-to-person contact. Infections have spread through day care centers and from feces of infected people.

Symptoms and Duration

Common symptoms include severe diarrhea that can be bloody, severe abdominal pain, and vomiting. Symptoms of HUS, a type of kidney failure associated with E. coli, include decreased urine production, dark or tea-colored urine, and pale facial skin. An E. coli infection typically lasts 5-10 days with most people feeling better without treatment in about 6-8 days. If HUS develops, it is usually about 7 days after the first symptoms and when diarrhea has improved, according to the CDC.

Who is most at risk?

While children under the age of 5 and older adults are more likely to develop serious illness and HUS, healthy older children and adults can also become ill. Other groups at increased risk for serious illness include pregnant women and those with weak immune systems like those with cancer, diabetes, or HIV/AIDS.

How to prevent it

• Hand washing is the easiest way to avoid E. coli infection, particularly before preparing food, after contact with animals, after using the bathroom or after changing a diaper
• Cook ground beef to a safe internal temperature of 160 degrees Fahrenheit to reduce the risk of E. coli infection, as recommended by Michigan State University Extension
• Avoid high-risk foods such as unpasteurized milk or juice, soft cheeses made from unpasteurized milk, alfalfa sprouts or undercooked ground beef
• Avoid cross-contamination in the kitchen, whether by raw and ready-to-eat food touching or by shared utensils between the two types of food
• Avoid swallowing water when swimming in lakes, ponds, streams, pools and backyard kid-sized pools

The CDC states that to reduce the risk of infection when around animals or animal barns:

• Wash hands thoroughly and frequently and supervise children’s handwashing
• Avoid eating or drinking in areas where animals live and eat
• Keep children from putting their hands in their mouths
• Do not take strollers, pacifiers, cups,or toys into animal areas

For more information on E. coli, check out the sources listed below. Check back next month to continue learning more about the big six pathogens from MSU Extension.

Other articles in this series

• Introduction
• Shigella
• Salmonella
• Viruses