Baseline Trachoma Mapping in Malawi with the Global Trachoma Mapping Project (GTMP)

ABSTRACT

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.

• Blindness
• epidemiology
• Malawi
• mapping
• neglected tropical diseases
• prevalence
• trachoma
• trichiasis

ACKNOWLEDGMENTS

We would like to acknowledge the contributions by the following individuals and organizations during the survey period: Ministry of Health for providing staff, District Health Management teams for all the recorders and graders, the Health Surveillance Assistants and the community volunteers that took part in the survey.

The Global Trachoma Mapping Project Investigators are:

Methodologies Working Group: Simon J. Brooker, Paul Emerson, Katherine Gass, Danny Haddad, Jonathan D. King, Chad MacArthur, Els Mathieu, Beatriz Muñoz, Erik Harvey, Jeremiah Ngondi (lead), Stephanie Ogden, and Anthony W. Solomon.

Prioritisation Working Group: Simon Bush, Paul Courtright, Paul M. Emerson, Allen Foster (lead), Danny Haddad, Richard Le Mesurier, Silvio P. Mariotti, and Anthony W. Solomon.

Tools Working Group: Erik Harvey, Jonathan D. King, Thomas M. Lietman, Alexandre L. Pavluck, Joseph Pearce, Anthony W. Solomon (lead), and Sheila K. West.

Training Working Group: Agatha Aboe, Paul Courtright (lead), Jonathan D. King, Susan Lewallen, Chad MacArthur, Silvio P. Mariotti, Els Mathieu, Jeremiah Ngondi, Anthony W. Solomon, Jennifer L. Smith, and Sheila K. West.

ITI Technical Team: Brian Chu, Rebecca M. Flueckiger, Alexandre L. Pavluck, and Rebecca Willis.

DECLARATION OF INTEREST

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Financial support was received from the United Kingdom's Department for International Development, through its Global Trachoma Mapping Project grant to Sightsavers.