Introduction
Salmonella typhi is the causative agent of typhoid fever. According to the CDC, there are only about 400 cases of typhoid fever in the United States every year, but elsewhere typhoid fever is much more prevalent, with over 20 million cases worldwide every year. Typhoid fever is a life-threatening infection that affects multiple organ systems, often with severe complications.
How it Spreads
Infection starts in the digestive tract and gets into the bloodstream through which it can be disseminated throughout the body in severe cases. Sometimes, it settles in the gallbladder, and a "carrier" state develops with continuous shedding of the bacteria in feces and urine.
Infection is usually spread by human-to-human contact, through food contaminated by carriers, water supply contaminated by sewage or food washed with contaminated water. The disease is thus more prevalent in areas of the world with poor water quality or a scant supply of water. Spread is further encouraged in cultures where hand washing is not strongly practiced. Typically, a food handler is a carrier and continues to spread the infection without being aware of it.
The World Health Organization (WHO) classifies typhoid fever as a water-related disease, which means it is associated with poor or contaminated water supply. The majority of the cases in the United States are travel-related, with the patient or a close relation returning from a trip to an area with less than sanitary water supplies.
Prevention
Recommendations for the prevention of the spread of Salmonella typhi revolve around basic hygiene. Regular hand washing can minimize the spread of the infection. Proper hygiene in food handling can also curb the spread through infected food handlers. Avoid eating raw food outside your home, and peel fruits and vegetables. Avoid buying food from street vendors. Boil your water before drinking, drink bottled water or attach water filtration systems to your water supply.
Prompt and accurate diagnosis with stool cultures, followed by adequate antibiotic treatment, can eliminate the risk of developing the carrier status of the infection.
Vaccines have some protective effect, and are prescribed for those making trips to high-risk areas for typhoid fever. They are more likely to be effective if taken some weeks prior to the time of departure.
