Do you ever crave raw cookie dough? What about a rare hamburger? Although these foods may sound tempting, they can harbor a type of bacteria known as E. coli, short for Escherichia coli, a rod-shaped bacteria found in soil and water. These bacteria live in the intestines of humans and animals and are important for a healthy intestinal tract. However, certain strains of this bacteria can be harmful, and even deadly.

E. coli O157:H7 is one of those strains that, if ingested, can make humans very sick. Humans who consume this type of bacteria and become infected often have symptoms such as abdominal cramping, bloody diarrhea, and vomiting. Toxins produced by E. coli O157:H7, also known as the Shiga toxin-producing E. coli (STEC), cause these symptoms. If a news station is reporting on outbreaks of E. coli, chances are they are referring to the dangerous O157:H7 strain.

The most common way that humans become infected with E. coli is from coming into contact with feces that contains E. coli. People may also become infected with E. coli from working with animals like livestock, eating undercooked meat or raw vegetables, touching the unwashed hands of someone who has come into contact with harmful E. coli strains, or drinking contaminated water.

Other than staying hydrated, there are not many ways to treat an E. coli infection. Antibiotics are not effective at combatting the infection. Therefore, prevention is important. Washing hands thoroughly with soap, avoiding unpasteurized milk, thoroughly cooking meats, and avoiding drinking water from ponds, lakes, and public swimming pools are a few ways to avoid coming in contact with harmful strains of E. coli bacteria.

Some E. coli strains are used as indicators of contaminated water. National Geographic Explorer Ashley Murray is one scientist who studies water-related diseases and waste management. Murray works as the director of Waste Enterprisers in Ghana, a company that she founded, which owns and runs waste management businesses. Other institutes, like the National Institute of Allergy and Infectious Diseases (NIAID), are researching ways to improve detection, treatment, and prevention of E. coli.