Typhoid is usually transmitted by water or food, in much the same way as cholera. People who are infected excrete live bacteria in their feces and urine. They are usually contagious for a few days before any symptoms develop, so they don't know they need to take extra precautions. If they don't wash their hands properly, the typhoid bacillus can be transferred to food or water and from there to another person. Also, it can be spread directly from person to person via contaminated fingers.