Serodiagnosis (Widal Test) of Typhoid and Paratyphoid Fevers：A Retrospective Study

Abstract

A total of 188 patients with a bacteriologically-confirmed diagnosis of enteric fever, treated at Tokyo Metropolitan Komagome Hospital during 1975-2002, were retrospectively studied based on the described records on medical charts. Interpretation of the Widal titer results were defined as follows according to the instructions of the manufacturer, Denka Seiken, Co. Ltd, Tokyo：O agglutination；Salmonella Typhi ≧1：160,S. Paratyphi A ≧1：80, S. Paratyphi B ≧1：160, and Vi agglutination for S. Typhi ≧1：20. In symptomatic cases, positive results (sensitivity) were seen in 29 of 99 cases (29.3%) for typhoid fever, 8 of 47 cases (17.0%) for paratyphoid fever A, and 4 of 6 cases (66.7%) for paratyphoid fever B. In asymptomatic cases, positive results were 0 of 14 cases with S, Typhi (0%), 0 of 5 cases (0%) with S. Paratyphi A, and 2 of 17 cases (11.8%) with S. Paratyhi B. Positive results for Vi agglutination were obtained in 5 of 99 (5.1%) of symptomatic cases of typhoid fever, and one of 14 (7.1%) for asymptomatic cases yielding S. Typhi.

When we adopted 61 non-enteric fever cases (30 of malaria, 17 of dengue, 7 of hepatitis A, 4 of undetermined fever, and 3 miscellaneous diseases) as negative control, the specificity of the Widal O agglutination test was 100% for symptomatic cases of typhoid fever and paratyphoid fevers A and B.