Baseline trachoma mapping in Malawi with the Global Trachoma Mapping Project (GTMP)
Kalua, K., Phiri, M., Kumwenda, I., Masika, M., Pavluck, A., Willis, R., ... Solomon, A. W. (2015). Baseline trachoma mapping in Malawi with the Global Trachoma Mapping Project (GTMP). Ophthalmic Epidemiology, 22(3), 176-183. DOI: 10.3109/09286586.2015.1035793
Purpose: To determine the prevalence of trachoma in all suspected endemic districts in Malawi.
Methods: A population-based survey conducted in 16 evaluation units from 12 suspected endemic districts in Malawi (population 6,390,517), using the standardized Global Trachoma Mapping Project (GTMP) protocol. A 2-stage cluster-random sampling design selected 30 households from each of 30 clusters per evaluation unit; all residents aged 1 year and older in selected households were examined for evidence of follicular trachoma (TF), intense trachomatous inflammation (TI), and trachomatous trichiasis (TT).
Results: Four of the 16 evaluation units were found to be endemic for trachoma, with a prevalence range of 10.0–13.5% for TF and 0.2–0.6% for TT. Nine evaluation units had a TF prevalence between 5.0% and 9.9% while three evaluation units had a TF prevalence <5.0%.
Conclusion: The prevalence rates of active trachoma in Malawi were not uniform among suspected endemic evaluation units, with rates higher than the World Health Organization (WHO) threshold for implementation of community-based control measures (TF???10.0%) in only 4 of the 16 evaluation units. Trachoma remains a disease of public health importance in some parts of Malawi and adjoining (unmapped) districts should be prioritized for mapping. According to the survey, an additional 3,169,362 people require intervention to reduce active disease and 1557 trichiasis surgeries are needed to reduce the prevalence of TT below WHO recommended thresholds.