Prevalence of Salmonella typhi among Patients in Abeokuta, South-Western Nigeria

This study reports on the prevalence of typhoid fever between genders among patients in Abeokuta, Nigeria. Typhoid fever caused by Salmonella typhi is an endemic disease in the tropic and sub-tropic and has become a major public health problem in developing countries of the world with an estimated annual incidence of 540 per 100,000. The annual incidence of typhoid is estimated to be about 17 million cases worldwide. It is often encountered in tropical countries including Nigeria where they constitute serious sources of morbidities and mortalities. Blood samples were collected from 840 apparently healthy people; 460 (54.8%) females and 380 (45.2%) males. The samples were examined for the presence and levels of Salmonella typhi antibodies by Widal agglutination technique. The standard Samonella 'O' and 'H' suspension (ANTEC diagnostic products) were used as antigens. Of the 840 sera tested, agglutinins to Salmonella typhi were most prevalent in female subjects accounting for [426(92.6%)] of the 'H' antigens and [322(70.0%)] of 'O' antigens at the various dilutions while in the male subjects, [351(92.4%)] accounts for the 'O' and [327(86.1%)] for the 'H' antigens. There was a female preponderance (F/M 2:1). The levels of agglutinin of Salmonella paratyphi C-H [93(24.5% )] and Salmonella typhi C-O [112(29.5%)] in the males were however, low. In the females, the low significant agglutinin titres for Salmonella typhi O and Salmonella paratyphi A-O were observed in 27.6% and 36.1% of the sera respectively. The results of this study showed that more males had Salmonella agglutinin titres for S. typhi O [351(92.4%)] and S. typhi H [327(86.1%)]. More so, 132 (34.7%) males had Salmonella agglutinin titres for S. paratyphi A-O, 119 (31.3%) for S. paratyphi B-O, 112 (29.5%) for S. paratyphi C-O, 117 (31.0%) for S. paratyphi A-H, 125 (33.0%) for S. paratyphi B-H, and 93 (24.5%) for S. paratyphi C-H. It also showed that more females had Salmonella agglutinin titres for S. typhi H [426 (92.6%)] followed by S. typhi O [322(70.0%)], S. paratyphi B-H [168 (36.5% )], S. paratyphi B-O [163(35.4%)], S. paratyphi B-O [147(32.0%)], S. paratyphi C-O [145(31.5%)], S. paratyphi A-H [142 (31.0%)], and S. paratyphi C-H [130 (28.3%)]. Since the positive sera with titres of less than 1:80 occurred in more than 5% of the samples tested, this study therefore suggests that such titres be regarded as normal among the communities studied while there should a high index of suspicion of clinical infections in titres above 1:80 when a second serum is impractical. The findings of this study further establishes the Salmonella typhi titres that are not diagnostically significant but normal in the study population and the titre that could be used as presumptively diagnostic of typhoid fever. This will improve accurate diagnosis. Improving accurate diagnosis is the surest way to reverse the deteriorating health status of Nigerians. Poor diagnosis leads to emergence of resistant strains of diseases. It also further establishes the Salmonella typhi titres that are not diagnostically significant but normal in the study population and the titre that could be used as presumptively diagnostic of typhoid fever.