Identification of carriers among individuals recruited in the typhoid registry in Malaysia using stool culture, polymerase chain reaction, and dot enzyme immunoassay as detection tools.

Chronic carriers of Salmonella Typhi act as reservoirs for the organism and become the agents of typhoid outbreaks in a community. In this study, chronic carriers in Kelantan, Malaysia were first identified using the culture and polymerase chain reaction method. Then, a novel serological tool, designated Typhidot-C, was evaluated in retrospect using the detected individuals as control positives. Chronic carriage positive by the culture and polymerase chain reaction method was recorded at 3.6% (4 out of 110) among individuals who previously had acute typhoid fever and a 9.4% (10 out of 106) carriage rate was observed among food handlers screened during outbreaks. The Typhidot-C assay was able to detect all these positive carriers showing its potential as a viable carrier screening tool and can be used for efficient detection of typhoid carriers in an endemic area. These findings were used to establish the first carrier registry for S Typhi carriers in Malaysia.

Toll-like receptor 4 Asp299Gly and Thr399Ile polymorphisms and typhoid susceptibility in Asian Malay population in Malaysia.

Typhoid fever is a major health problem with frequent outbreaks in Kelantan, Malaysia. Prevalence of TLR4 gene polymorphisms varies with ethnic groups (0-20%) and predisposean individual to gram-negative infections. The prevalence rate of TLR4 Asp299Gly and Thr399lle polymorphisms in the Malay population or the influence of these on typhoid fever susceptibility is not yet reported. 250 normal and 304 susceptible Malay individuals were investigated for these polymorphisms using allele-specific PCR and analysed for its association with typhoid fever susceptibility. The total prevalence of polymorphisms in the normal population was 4.8% in comparison to 12.5% in the susceptible population (p = 0.002). An increased frequency of both polymorphisms was observed in the susceptible population (p < 0.01) with no homozygous mutants observed. Co-segregation was observed in 2% of controls and 3.6% of the susceptible individuals. This study, for the first time, reports the prevalence of TLR4 gene polymorphisms in the Malay population and suggests that these polymorphisms confer a higher risk for typhoid, infection. The higher incidence of typhoid fever in Kelantan could be attributed to the higher percentage of Malays (95%) in this state. In order to reduce the incidence of this disease, people with these polymorphisms, can be prioritised for prophylactic strategies.