E. coli is contagious from person to person, though this is much less common than direct contamination from another source, according to Everyday Health. The most common way to spread E.coli bacteria is leaving traces of contaminated feces on an object that another person inserts into the mouth.
E. coli is most commonly contracted in humans by consuming undercooked meats or raw milk, according to MedicineNet.com. The bacteria that causes the illness is found in the feces of animals and spread when traces are not cooked out of meat or processed out of milk.
Everyday Health explains that humans do not pass the bacteria through interactions such as kissing or touching. However, it is possible for people to leave traces of E. coli on objects or food if they do not wash their hands with soap after using the bathroom or handling diapers. Those infected with E. coli should not swim in public pools or ponds for several months after first experiencing symptoms in order to prevent spreading the bacteria.