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Seroepidemiology of enteric fever and brucellosis in a developing country
A Hossain1, T F Bakir, M N Chowdhury
1Department of Microbiology and Immunology Faculty of Medicine, University of Montreal, Quebec, Canada.
Insights
This study investigated Salmonella typhi and Brucella infections in Middle Eastern children and adults. Brucellosis was more prevalent than typhoid fever, with the Rose Bengal test showing promise for diagnosis.
Area of Science:
- Medical Microbiology
- Epidemiology
- Immunology
Background:
- Sub-tropical regions, particularly developing countries in the Middle East, face significant public health challenges from infectious diseases.
- Salmonella typhi (S. typhi) causes typhoid fever, while Brucella species (spp.) cause brucellosis, both posing risks in endemic areas.
Purpose of the Study:
- To investigate the seroepidemiology of S. typhi and Brucella spp. infections in a sub-tropical developing country.
- To evaluate the diagnostic utility of agglutination tests, including the Widal test for enteric fever and serological tests for brucellosis.
Main Methods:
- Sera from 130 children, 117 young adults, and 40 older adults were tested for antibodies against S. typhi, B. abortus, and B. melitensis using agglutination tests.
- The Widal test was used for suspected enteric fever cases (244 patients), and agglutination tests for suspected brucellosis (138 patients).
- The Rose Bengal Antigen Slide Agglutination Test (Brucelloside Test) was comparatively evaluated for brucellosis diagnosis.
Main Results:
- Low prevalence (4.5%) of S. typhi antibodies (titers ≥80) was observed in children and adults.
- Prevalence rates for Brucella antibodies (titers ≥80) were 11.6-13.1% in children and 11.3-12.4% in adults for B. abortus and B. melitensis.
- Among suspected brucellosis cases, 29 culture-proven cases were confirmed serologically, with titers ≥640, and an additional 90 cases were detected serologically. B. melitensis was the primary isolate.
Conclusions:
- Brucellosis appears more prevalent than typhoid fever in the studied population.
- Agglutination tests are useful for diagnosing brucellosis in endemic areas.
- The Rose Bengal Antigen Slide Agglutination Test demonstrates potential as an effective screening tool for human brucellosis serodiagnosis.
Abstract:
The seroepidemiology of infection due to S. typhi and Brucella spp. in a sub-tropical, developing country of the Middle East was investigated in 130 children of age less than 1 to 15 years, 117 young adults (16-30 years) and in a further 40 adults (greater than 30 years) using an agglutination test to detect antibodies to of S. typhi, B. abortus and B. melitensis. Only 4.5% of the children's and adult's sera respectively showed the presence of antibodies to both O and H antigens of S. typhi with reciprocal titers greater than or equal to 80. Prevalence rates of 11.6%, 11.3% respectively in children and adults of antibodies to B. abortus with reciprocal titers greater than or equal to 80 and similarly 13.1%, 12.4% to B. melitensis were found. The usefulness of a single Widal test to diagnose enteric fever in a non-endemic area and the agglutination test in the diagnosis of brucellosis in an endemic area was investigated. Of 244 patients with suspected enteric fever, the sera of 100 showed reciprocal antibody titers 80 to both O and H antigens and included in these were 8 patients with concurrent culture positivity. Among 138 children and adults with suspected brucellosis, 29 culture proven cases where serologically confirmed and a further 90 were detected serologically. The sera of all the culture proven cases exhibited antibody reciprocal titer greater than or equal to 640. A similar antibody response was noted in seventy-two of the culture negative cases diagnosed serologically for brucellosis. In culture proven, cases B. melitensis was the isolate. Comparative evaluation indicated the potential usefulness of the Rose Bengal Antigen Slide Agglutination Test (Brucelloside Test) as a screening test in the serodiagnosis of human brucellosis.