Typhoid fever is caused by the bacteria Salmonella typhi, which spreads through contaminated food, water, or drink. It causes symptoms like high fever, abdominal pain, and diarrhea. The bacteria enters the intestines and bloodstream. It is diagnosed through blood tests and cultures. Typhoid fever is treated with antibiotics and fluids, though antibiotic resistance is increasing. With treatment, symptoms usually improve within 2-4 weeks, but complications can occur like intestinal bleeding or perforation. Vaccination is recommended for travel to areas where typhoid fever is common.