Typhoid fever is a life-threatening illness caused by the Salmonella Typhi bacterium. It affects approximately 12.5 million people worldwide each year. The disease is contracted through ingestion of contaminated food or water. Symptoms include sustained high fever, abdominal pain, diarrhea or constipation. While antibiotics have reduced the fatality rate to 1-2%, drug-resistant strains are an increasing problem. Vaccines can help prevent infection for those traveling to areas where the disease is common.