Typhoid Fever as a Challenge for Developing Countries and Elusive Diagnostic Approaches Available for the Enteric Fever

Salmonella typhi is the causal organism for the typhoid fever. Typhoid disease is a problem in those developing countries where lack of sanitation, poor water supplies and exposure to unhygienic and polluted environment is a part of routine life of majority of population. Salmonella typhi expresses various virulence antigens like H-antigens, O-antigens and Vi antigens which plays vital role in the infection and pathogenesis of the bacteria. Salmonella typhi causes fever, nausea, headache, body fatigue and bowel related complications in the patients. This disease had been diagnosed by culture method, Widal test for past several decades. These diagnostic techniques are being replaced by the modern assays like ELISA, Dot blot ELISA, DipStick Assays, RT-PCR and other molecular assays. The evolution in diagnostic assays had occurred as the antibiotic resistance in the Salmonella typhi had shown an increase. The Salmonella typhi had been evolved into a multidrug resistant bacteria which need to be timely diagnosed to start the appropriate and correct treatment of typhoid to prevent further complications. This article imparts a brief glimpse on Salmonella typhi, typhoid fever and diagnostic assays available at clinical laboratories. There is a need to focus on the correct and rapid diagnostic methods which should be modified and made accessible to the clinical diagnostic laboratories. Keywords: Salmonella typhi; Virulence Antigens; Typhoid; Vaccines; Diagnosi