ADDITIONAL INFORMATION

After Salmonella is eaten it passes through the stomach to the intestine. Here, it binds to the wall of the intestine, and through some special proteins that it makes in response to the particular conditions in the intestine it actually penetrates the barrier between us and the outside. Once it has gained access to our insides, it is taken to the liver or spleen. For most other bacteria, this journey would kill them, however Salmonella has evolved mechanisms to prevent our immune system from doing its job efficiently. In the liver, the Salmonella can grow again, and be released back into the intestine. Of course, not all of the Salmonella pass through the intestinal wall, and many of them are expelled from the intestine in the diarrhea. In regions with poor sanitation, these bacteria can than survive in the soil or in rivers and infect the next person, cow, chicken or mouse that comes along. In the last 20 years or so, S. Enteritidis has become the single most common cause of food poisoning in the United States. S. Enteritidis causes a disease almost identical to the very closely related S. Typhimurium. S. Enteritidis is particularly adept at infecting chicken flocks without causing visible disease, and spreading from hen to hen rapidly. Many people have blamed the recent increase in the rise of S. Enteritidis infections on the use of mass production chicken farms. When tens or hundreds of thousands of chickens live together, die together, and are processed together a Salmonella infection can rapidly spread throughout the whole food chain. A compounding factor is that chickens from a single farm may be distributed over many cities, and even states, and hence Salmonella infections can be rapidly dispersed through millions of people. Until recently the most common cause of food poisoning by Salmonella species was due to S. Typhimurium. As its name suggests, it causes a typhoid-like disease in mice. In humans S. Typhimurium does not cause as severe disease as S. Typhi, and is not normally fatal. The disease is characterized by diarrhea, abdominal cramps, vomiting and nausea, and generally lasts up to 7 days. Unfortunately, in immunocompromized people, that is the elderly, young, or people with depressed immune systems, Salmonella infections are often fatal if they are not treated with antibiotics.