Diseases

Prevention and Control of Typhoid

Theoretically typhoid is an eradicable (as smallpox) disease as Salmonella that cause enteric fever survive only in human hosts and are spread by contaminated food and water. But high prevalence of typhoid in developing countries and lack of adequate sewage disposal and water treatment make the goal of eradication of typhoid impracticable at present. So travelers from developed countries to developing country should monitor their food and water intake carefully and also get vaccinated for typhoid.

Typhoid vaccines:

At present 2 types of typhoid vaccines are commercially available: (1) Ty21a, an oral live attenuated vaccine of Salmonella Typhi (given on days 1, 3, 5, and 7, with a booster every 5 years) and (2) Vi CPS, a parenteral vaccine (given intramuscularly) consisting of purified Vi polysaccharide from the bacterial capsule (given in 1 dose, with a booster every 2 years). The older vaccine of whole cell typhoid/paratyphoid A and B vaccine (given intramuscularly) is no longer licensed due to its side effects. The minimum age for vaccination is 6 years for oral type or Ty21a and 2 years for Vi CPS. At present there is no vaccine licensed for paratyphoid. An acetone-killed whole-cell vaccine is available which is only used by the U.S. military.

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Diagnosis of Typhoid Fever

The clinical features of typhoid fever are nonspecific. So diagnosis of typhoid fever should be considered if a traveler returning from developing country with fever, especially from Indian subcontinent, and Latin America or in developing countries any patient with fever. Other diagnosis to be considered in case of fever and international travel are malaria, hepatitis, bacterial enteritis, dengue fever, rickettsial infections, leptospirosis, amebic liver abscesses, and acute HIV infection etc.

A positive blood culture is the only confirmatory test for diagnosis of typhoid fever and other laboratory tests are not diagnostic. There may be non specific laboratory changes like leukopenia and neutropenia in 15% to 25% of the cases of typhoid fever and also moderately elevated liver function tests and muscle enzyme levels.

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Typhoid Fever: Clinical Features

Typhoid Fever: an Understanding