Typhoid fever, also known simply as typhoid, is a symptomatic bacterial infection due to Salmonella typhi. Symptoms may vary from mild to severe and usually begin six to thirty days after exposure. Often there is a gradual onset of a high fever over several days. Weakness, abdominal pain, constipation, and headaches also commonly occur. Diarrhea and vomiting are uncommon. Some people develop a skin rash with rose colored spots. In severe cases there may be confusion.