1) Typhoid fever is caused by the bacterium Salmonella typhi and results in an estimated 21 million cases and 200,000-600,000 deaths globally per year. India reported over 1 million cases and 346 deaths in 2011.
2) S. typhi is transmitted through the fecal-oral route, often through contaminated food or water. Risk factors include being male and between ages 5-19. Chronic carriers can harbor the bacteria in their gallbladder for many years and spread infection.
3) Control measures include proper sanitation, safe drinking water, identifying and treating chronic carriers, and vaccination programs. Both parenteral and oral vaccines are available but require booster shots to maintain protection.