Salmonella refers to a genus of rod shaped bacterium, named after their discoverer Daniel Salmon in 1906. Some of these salmonella bacterium are responsible for many illnesses in humans and other animals. Most commonly, salmonella is the cause of food poisoning and typhoid fever. Salmonella lives in the intestines of mammals, birds and reptiles and is usually harmless.

The type of salmonella that is a health hazard is usually contracted by touching raw meat, raw eggs, raw shellfish or unpasteurized animal products such as milk and cheese. Salmonella bacterium can also be acquired by touching living turtles, birds and humans that have the bacteria on their hands. Salmonella is not a threat until it is ingested, which is one reason why hand washing is important.

Salmonella food poising is the result of touching or eating contaminated foods. Its symptoms include diarrhea, vomiting, abdominal cramps and fever. Many foods that people prepare in their home, especially meats and poultry, have warning labels about safe handling on the packaging for this reason. Meat that is not properly cooked or food that is not temperature controlled is often the result of salmonella poisoning when eating out.

Salmonella poisoning usually goes away on its own without treatment in 5-7 days. However, if vomiting and diarrhea are severe and prolonged, a person can become dangerously dehydrated and must seek medical help. In addition, infected infants, the elderly and people that have weak immune systems often need medical care because salmonella sometimes spreads to the blood stream and can possibly become fatal.

Typhoid fever is a strain of salmonella similar to that which causes food poisoning, but more severe. Unlike salmonella poisoning, typhoid fever does not resolve itself and must be treated with specific antibiotics. A person who has been treated for typhoid fever may still be contagious to others for days, weeks or years, even though that person no longer has symptoms.

Typhoid fever is not common in western countries. Rather, it is found in contaminated water and food supplies of some developing countries. Typhoid fever is mainly spread through the ingestion of feces and urine. In countries that do not have adequate sewage disposal, human and animal wastes pollute the same water that is used for drinking, cooking and hand washing. Left untreated, typhoid fever is fatal.