Typhoid fever is an infectious disease caused by the bacterium Salmonella typhi. It is considered a serious disease which has constant fever, intestinal disorders, increase the viscera and if left untreated can occur confusion and lead to death.

The main form of transmission is by ingestion of contaminated food and water and these are scattered all over the world but occurs most often in countries where sanitation is poor or nonexistent. Food and water in turn, are infected through contact with urine and human feces containing the bacterium. There may be a direct infection carried by hand to mouth in cases of dirty hands of feces, urine, respiratory secretions, vomit or pus infected, but this type of infection is very rare.

Gastric acid is the first to react against salmonella, but the bacteria normally resistant to this attack and moves to the small intestine where it invades the intestinal wall and reaches the bloodstream. From the moment the salmonella reaches the bloodstream, symptoms begin to appear. The salmonella can enter any organ and multiply inside the cells of defense. Normally salmonella invades the liver, spleen, bone marrow, gall bladder and intestine.

The infection with Salmonella is global, but in Brazil the largest number of registered cases are concentrated in the North and Northeast and in Bahia and Amazonas states of higher occurrence.
The signs and symptoms are: high fever, headache, malaise, poor appetite, relative bradycardia, splenomegaly, pink patches on the trunk of the body, diarrhea and dry cough.

Typhoid fever can be more severe in people with poor health. Treatment relies on antibiotics and rehydration processes of the body. Depending on the patient's condition, treatment may be done at home with oral medication.