Determination of Antibody Titres and Isolation of Salmonella species in Suspected Enteric Fever Patients
A total of 1,016 patients attending the University of Calabar Medical Centre with symptoms of fever resembling typhoid and enteric fever were used for this study. Fifty-five healthy controls from the University Community were also studied. Serum samples from patients and controls were screened for Salmonella antibodies using Widal test. Blood samples and stools from patients and controls were cultured in Thioglycollate and Desoxycholate agar respectively. Out of 1,016 patients screened, 115 (11.3%), 169 (16.6%), 435 (42.5%) and 483 (47.5%) had Salmonella ‘H' antibody titres > 160 for S. paratyphi A, S. paratyphi B, S. paratyphi C and S. typhi respectively. The ‘O' antibody titres were distributed as follows: 142 (14%) for S. paratyphi A, 400 (39.4%) S. paratyphi B, 510 (50.2%) S. paratyphi C and 528 (52%) for S. typhi. Ninety-one percent of the control population had titres < 160 and these were mainly antibodies to S. paratyphi serotypes. Blood and stool cultures yielded 6% and 12% isolation rates respectively. These appeared low compared with other studies in developed countries and may possibly be due to indiscriminate use of antibodies with consequent reduction in the recovery rate of salmonellae. To this end, the Widal test is still a useful diagnosis test.
Keywords: Salmonella typhi, S. paratyphi, diagnostic antibody titre, blood, stool cultures, Widal test.
Journal of Medical Laboratory Science Vol. 13 (2) 2004: pp. 38-44