Typhoid fever is unique to humans. It remains a significant health problem in many developing countries, and poses a risk to travelers who visit such endemic regions. The proportion of cases acquired in foreign countries has continued to rise, reaching 70% in 1984. The risk of typhoid fever should not be underestimated as a travel-related illness.
The incidence of typhoid fever in the united states has decreased from one case per 100,00 population in 1955 to about 0.2 cases per 100,000 in 1966, and has since remained the same. However, international travelers account for more than two-thirds of the reported cases. The percentage of imported cases increased from 33% during 1967 through 1972, to 70% during 1983 through 1984. The majority of the imported cases were from mexico (39%) and india (15%). During the decade 1975 through 1984, 43% of travel-associated cases were non-U.S. citizens. the risk of acquiring typhoid varied from country to country and was the highest for travelers to india and pakistan, with over 400 cases per million, compared with mexico, with 34 per million, and europe, with 0.6 cases per million travelers.