Typhoid fever is still a deadly disease in developing countries, particularly in India. Although, the paediatric population is mostly affected by this disease, yet the disease is an important cause of morbidity and mortality in adult populations also. In India, most of the cases of typhoid fever are diagnosed clinically, or at the most by the Widal test which is not fool proof. The disease typhoid fever is an orally transmitted communicable infectious disease caused by the bacteria Salmonella typhi. It is usually caused by consuming impure water and contaminated food. Salmonella typhi is serologically positive for lipopolysaccharide antigens O9 and O12, protein flagellar antigen Hd, and polysaccharide capsular antigen Vi. S. typhi Vi-positive strains are more infectious and virulent than Vi-negative strains. Following the incubation period of 7 to 14 days, there is onset of fever and malaise. The fever is then accompanied by chills, headache, malaise, anorexia, nausea, vague abdominal discomfort, dry cough and myalgia. These are followed by coated tongue, tender abdomen, hepatomegaly, and splenomegaly. Azithromycin (10mg/kg) given once daily for seven days has proven effective in the treatment of typhoid fever in some adults and children. A dose of 1g per day for five days was also found to be more effective in most adults. Of the third generation cephalosporins, oral Cefixime (15-20mg per kg per day, for adults, 100-200mg twice daily) has been widely used. Intravenous third generation cephalosporins (ceftriaxone, cefotaxime) are effective. Aztreonam and imipenem are potential third line drugs.
Molecular analysis of isolates of Salmonella typhi obtained from patients with fatal and nonfatal typhoid fever.
