Epidemiology of typhoid and paratyphoid fever in India.

Enteric fever (typhoid and paratyphoid fever) is a major human bacterial infection. Although the disease is not common in industrialised countries, it remains an important and persistent health problem in developing nations. Hospital-based studies and outbreak reports from India indicate that enteric fever is a major public health problem in this country, with Salmonella enterica serovar Typhi (S. Typhi) the most common aetiologic agent but with an apparently increasing number of cases due to S. Paratyphi A (SPA). Because risk factors such as poor sanitation, lack of a safe drinking water supply and low socio economic conditions in resource-poor countries are amplified by the evolution of multidrug resistant salmonellae with reduced susceptibility to fluoroquinolone, treatment failure cases have been reported in India, which is associated with increased mortality and morbidity. Vaccination, which requires strict planning and proper targeting of the vulnerable age groups, is considered to be an effective tool in controlling this disease in endemic areas, given there is development of a conjugate vaccine against both serovars (S. Typhi and S. Para A).