Generality
Abdominal typhus - or typhoid fever - is a systemic (involving the whole organism) infectious disease caused by the bacterium Salmonella enterica serotype typhi.
The agent responsible for typhus is present in the urine and feces of infected people, and can be transmitted from human to human via the fecal-oral route through the ingestion of contaminated food or drink.
Typhoid fever is common in less industrialized countries, mainly due to limited access to drinking water, inadequate wastewater disposal, and flooding. Due to the way the infection spreads, typhoid fever is more common in parts of the world that have low levels of sanitation. The annual incidence of typhoid fever is estimated to be around 17 million cases worldwide.
Salmonella typhi
The causative agent of typhoid fever is the Salmonella typhi, whose vector can only be human. Therefore, the infection is always transmitted from one human being, sick or healthy carrier of the bacterium, to another. The incubation period can vary depending on the infectious dose, but is usually 1-3 weeks.
After ingestion of contaminated food or water, bacteria invade the small intestine and temporarily enter the bloodstream. There Salmonella typhi it initially multiplies in the cells of the liver, spleen and bone marrow, and then re-enters the blood. When the organism spreads into the bloodstream, patients develop symptoms, including fever. The bacteria invade the gallbladder, the biliary tract and the lymphoid tissue associated with the intestine. Here, they multiply in large numbers and then pass into the intestinal tract. In this phase the pathogens can be identified, for diagnosis, in tested stool cultures. in the laboratory.
Infection
Typically, typhoid fever is contracted by ingesting bacteria present in contaminated food or water.
There Salmonella typhi it has a remarkable resistance in the external environment, especially if contained in organic materials: bacteria can survive for weeks even in sewage and mud.
Patients with the disease can contaminate water through faeces, which during the acute phase of infection contain a "high concentration of bacteria." Bacterial pollution of the water supply can, in turn, contaminate the food supply. a healthy person eats food or drink that has been contaminated with a small amount of feces or urine in which the Salmonella typhi, you can get the infection.
Also, if infected patients do not wash their hands properly after going to the bathroom, they can contaminate food or the surfaces they touch, contributing to the spread of the infection.
Other ways typhoid fever can be contracted are:
- Eating shellfish or seafood from a water source that has been contaminated with infected feces or urine;
- Having sexual intercourse (oral or anal) with a person who is a carrier of Salmonella typhi.
Carrier status can follow acute illness. If typhoid fever is not treated, it is estimated that one in 20 people will become a carrier of the condition in the long term, even if asymptomatic. This means that the excretion of Salmonella typhi from the organism of chronic carriers can continue and last for more than 1 year.
Symptoms
To learn more: Typhus Symptoms
If the infection is left untreated, symptoms develop over the course of four weeks, with manifestations continually worsening. As the condition progresses, the risk of developing complications increases. With treatment, symptoms should rapidly improve within 3-5 days.
