Typhoid fever is a severe infection caused by a bacterium, Salmonella typhi. S. typhi is in the same family of bacteria as the type spread by chicken and eggs, commonly known as salmonella poisoning or food poisoning. S. typhi bacteria do not have vomiting and diarrhea as the most prominent symptoms of their presence in humans. Instead, persistently high fever is the hallmark of S. typhi infection. The Belgian data for foodborne norovirus (NoV) outbreaks showed that in 2007, 10 NoV foodborne outbreaks were reported accounting for 392 cases in Belgium.
After the ingestion of contaminated food or water, the Salmonella bacteria invade the small intestine and enter the bloodstream temporarily. The bacteria are carried by white blood cells to the liver, spleen, and bone marrow. The bacteria then multiply in the cells of these organs and reenter the bloodstream. Patients develop symptoms, including fever, when the organism reenters the bloodstream. Bacteria invade the gallbladder, biliary system, and the lymphatic tissue of the bowel. Here, they multiply in high numbers. Researches are focusing on the prevention of multi-drug resistence for the effective treatment of typhoid or enteric fevers.