Dehydration, especially among the young, the elderly and those with impaired immune systems, can be severe, and the person may become ill enough to be hospitalized. The infection can result in death unless the person is treated promptly with antibiotics. An infected person remains infectious throughout the illness, and may continue to excrete the bacteria for a while after symptoms have stopped, making good personal hygiene very important. Infection is acquired by the ingestion of organisms in food contaminated by the stool of an infected animal or person. The most common food sources include raw and undercooked eggs and egg products, raw milk and raw milk products, contaminated water, meat and meat products, poultry and poultry products and raw fruits and vegetables.
Pets are another common source of infection.
The bacteria can be carried by iguanas, turtles, tortoises, chicks, and sometimes cats and dogs. Farm animals may become infected through the ingestion of feeds and fertilizers prepared from contaminated meat scraps, tankage, fish meal and bones. Hands should be washed before, during and after preparing food. Prepared foods should be refrigerated in small containers. Food derived from animal sources, especially poultry, pork, egg products and meat dishes, should be thoroughly cooked.