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[Risk of Mycobacterium tuberculosis infection in Jalisco, Mexico]
S Gloyd1, J L López, F J Mercado
1Universidad de Washington, Escuela de Salud Pública y Medicina Comunitaria, Departamento de Servicios de Salud, Seattle 98195.
Insights
Tuberculosis (TB) infection risk is higher than registered cases in Jalisco, Mexico. This study estimated the annual risk of infection from Mycobacterium tuberculosis in 4,083 children using tuberculin skin tests.
Area of Science:
- Epidemiology
- Infectious Diseases
- Public Health
Context:
- Tuberculosis (TB) remains a significant global health concern, necessitating accurate incidence estimations.
- Mexico, like many countries, faces challenges in controlling TB transmission.
- Understanding the prevalence of Mycobacterium tuberculosis infection in pediatric populations is crucial for public health interventions.
Purpose:
- To estimate the annual risk of Mycobacterium tuberculosis infection among first-grade children in Jalisco, Mexico.
- To compare TB infection rates in urban (Guadalajara) versus rural areas of Jalisco.
- To assess the impact of BCG vaccination scars on tuberculin skin test (TST) results.
Summary:
- A modified cluster sample design involved 4,083 first-grade children, administering 2 TU PPD skin tests.
- Statewide, 6.8% of children exhibited PPD reactions (≥10 mm induration).
- The estimated average annual risk of infection in unvaccinated children was 0.82%, suggesting underreporting of TB cases.
Impact:
- The findings indicate that the actual incidence of smear-positive pulmonary tuberculosis in Jalisco may be nearly 10 times higher than officially registered cases.
- This highlights a critical need for enhanced TB surveillance and control strategies in the region.
- The study provides valuable data for policymakers to allocate resources effectively for TB prevention and treatment programs.
Abstract:
Using a modified cluster sample design, skin tests with two TU PPD were performed on 4,083 first-grade children (mean age 6,7 years) in the state of Jalisco, Mexico, to estimate the annual risk of infection from Mycobacterium tuberculosis. The proportion of PPD reactions (a diameter of 10 mm or more of induration) was 7.6% in the Guadalajara metropolitan area and 5.5% in the rest of Jalisco. In the total sample, the proportion was 7.4% among children with scars attributed to BCG vaccine and 4.5% in children without BCG scars. The weighted proportion of children with PPD reactions of 10 mm or more was 6.8% statewide. The average annual risk of infection estimated from the group that had not received BCG vaccine was 0.82%. The results suggest that the incidence of smear-positive pulmonary tuberculosis is almost 10 times greater than the number of cases registered annually in Jalisco.