Typhoid fever: Current concepts

Infectious diseases account for most of the 10 million annual deaths globally in children younger than 5 years. In recent years, data indicating that typhoid fever is a major cause of morbidity among the urban and periurban populations and the single most important cause of febrile bacteremia in febrile children has emerged. In several community-based studies from south Asia, the incidence rate seems to be especially high among young children, with rates exceeding 500 to 1000 cases per 100,000 population. In contrast, nontyphoidal salmonella infections in Africa seem to be an important cause of community-acquired bacteremia, especially among HIV-infected populations.Although isolated cases of chloramphenicol resistance in Salmonella typhi have been known for a long time, the mid 1980s saw the emergence of strains of S. typhi resistant to all the 3 primary oral antibiotics. In recent years, there has also been a marked increase in quinolone-resistant isolates. Although the exact determinants and factors associated with endemic disease and outbreaks of drug-resistant cases of typhoid are uncertain, there does seem to be an association with crowding, lack of sanitation and hygiene, and access to street foods.The appropriate and rapid diagnosis of typhoid remains a challenge with a variety of serological diagnostic tests and polymerase chain reaction-based techniques. Given the limited resources available for case management, appropriate antimicrobial therapy of multidrug- and quinolone-resistant typhoid poses particular problems in developing countries, especially because of the rapid emergence of resistant strains in recent years. Therefore, it is imperative that the focus clearly remain on preventive strategies for typhoid, including safe water, hygiene, and appropriate vaccination strategies.