Salmonella typhi and paratyphi are also more likely than other salmonella serotypes to cause enteric fever, as well as the chronic carrier state.
Typhoid fever is the most serious form of enteric fever, with humans being the sole reservoir of the bacteria. Based on a recent survey, the global number of typhoid cases in 2000 exceeded 21,000,000, with more than 200,000 deaths . Enteric fever, that is typhoid and paratyphoid fevers, is the common name for infections caused by Salmonella enterica serotypes typhi and paratyphi. Of the three types of S. paratyphi (A, B, and C), B is the most common.