Where Did Typhoid Fever Come From?

Transmission

The salmonella typhi bacteria cause typhoid fever, which is classified as an infectious disease. It is transmitted by ingesting contaminated water and food or is spread by human carriers. A tainted water supply is often responsible for contaminating food, as the bacteria can survive in water for up to two weeks. Water becomes contaminated by human waste in sewage. The bacteria are usually passed through feces, but can sometimes be passed through urine. Typhoid is known to spread quickly through water, milk and shellfish. People who suffer a mild case of the disease can become carriers over the long term. Often these individuals show no obvious symptoms of their own, but can infect others with the disease. Even after recovery, carriers continue to pass the bacteria through their feces. Removal of the gall bladder may be necessary for those who show no symptoms of the illness, as the gall bladder is often the site of the infection.

The bacteria responsible for typhoid fever attack the small intestine, entering the bloodstream. After infecting white blood cells in the liver, spleen and bone marrow, the bacteria then are transported to other organs where they multiply in the gall bladder or liver before passing into the bowel. It is at this point, they may develop symptoms including high fever. The incubation period is typically seven to 14 days.

Symptoms of the disease include high fever, chills, aches and pains throughout the body, diarrhea, bloody stools, general malaise, and headaches. Swelling of the lymph nodes, red spots on the chest, constipation, swollen spleen and abdominal pain are other symptoms people can suffer. Generally, it takes three or four weeks for the disease to run its course, however, in some cases, symptoms can last for up to six or eight weeks. Because the bacteria attack the gastrointestinal system, complications caused by the disease may require surgery to repair damage to the digestive tract. If left untreated, the disease can cause internal bleeding or even kill.

The bacteria that cause typhoid fever may have infected our human ancestors as long ago as 2 million years. Although there are more than 1,000 different strains of the bacteria, only a few cause typhoid. Man is the only host but the bacteria invade the intestine, inflaming tissue. The disease was prevalent in the United States in the late 1900s and early 20th century. Both the oral vaccine and single dose injectable vaccine that are now available produce fewer side effects than earlier vaccines. Although the disease still affects millions of people throughout the world each year, data published by the Centers for Disease Control and Prevention estimates about only 400 cases occur annually in the United States.