Salmonella (S.) is the genus name for a wide variety (over 2,500) of bacteria. Each type can be distinguished by its particular protein coating. The types are very similar in all other aspects. Salmonella bacteria are flagellated, rod-shaped, Gram stain-negative, and are known to cause illness in humans, birds (especially poultry), and animals worldwide.
Salmonellosis most commonly causes food poisoning involving the symptoms of extreme stomach discomfort, nausea, vomiting, and diarrhea. Abdominal cramping is also a common symptom. Although food poisoning is usually a mild illness, vomiting, and diarrhea can lead to severe dehydration and even death (approximately 500 people die from Salmonella per year in the U.S.). It is important to note that many other organisms (including bacteria, viruses, toxins, and pesticides) can produce food poisoning symptoms. However, more than 1.4 million cases of salmonellosis occur every year in the United States, and the other industrialized countries have similarly high incidences. Where as, countries with poor sanitation have a much higher occurrence of salmonellosis.
Thyphoid fever is a complication of a Salmonella infection associated with the specific salmonellosis bacteria S. typhi. Typhoid fever occurs when some Salmonella cells survive the person’s immune system defenses. From the gastrointestinal tract, the Salmonella bacteria can move in to the spleen, liver, and other organs, where they can survive and grow. From the organs, the bacteria can then move into the blood (this is called bactermia). Salmonella can be secreted from the liver to the gallbladder, where they can continue to survive and be shed into the person’s feces for as long as a year. Symptoms of typhoid include high fevers (up to 104º F), inflammation of the stomach and intestines, profuse sweating, and diarrhea. Symptoms typically resolve, but many of these patients become Salmonella carriers. Nearly half of typhoid patients develop a slow heartbeat (this is known as bradycardia), and approximately 30% of patients get flat, slightly raised red spots on the abdomen and chest. Typhoid fever is also known as enteric fever.
Paratyphoid fever, which is also termed enteric fever, has symptoms much like typhoid fever, but is typically less severe. The subtypes are A, B, and C and vary by having small differences in symptoms, such as more red spots (subtype A), in conjunction with herpes labialis and gastroenteritis (subtype B), rarely, with septicemia (blood poisoning) and abscesses (subtype C).
Salmonella is typically transmitted to people through contaminated food. Contamination can come from human or animal feces that contacts the food during the processing or harvesting. Typhoid and paratyphoid can be transmitted in the same manner as salmonellosis, but more commonly the manner of transmission is by the feces from infected people contaminating the water or food source of uninfected people.
Heat kills Salmonella, so it is wise to cook meat, especially chicken all the way through. This will minimize the likelihood of infection. Selecting juices that are pasteurized aid in preventing the spread of Salmonella, since pasteurization is a heat treating process. It is always wise to thoroughly wash fruits and vegetable. Most importantly, people should always make an effort to wash their hands with soap and water after using the restroom.
