Typhoid fever is caused by the Salmonella Typhi bacteria and can spread through contaminated food, water, physical contact, and insects. Symptoms include high fever, headaches, constipation, diarrhea, skin inflammation, and enlarged spleen and liver. Treatment involves vaccinations, which are not always effective, and antibiotics, which only provide temporary relief. Typhoid Mary was an infamous carrier and spreader of typhoid fever through her work as a cook in New York in the early 1900s.