Validation of three geolocation strategies for health-facility attendees for research and public health surveillance in a rural setting in western Kenya

Understanding the spatial distribution of disease is critical for effective disease control. Where formal address networks do not exist, tracking spatial patterns of clinical disease is difficult. Geolocation strategies were tested at rural health facilities in western Kenya. Methods included geocoding residence by head of compound, participatory mapping and recording the self-reported nearest landmark. Geocoding was able to locate 72.9% [95% confidence interval (CI) 67.7 77.6] of individuals to within 250 m of the true compound location. The participatory mapping exercise was able to correctly locate 82.0% of compounds (95% CI 78.9-84.8) to a 2 x 2.5 km area with a 500 m buffer. The self-reported nearest landmark was able to locate 78.1% (95% CI 73.8-82.1) of compounds to the correct catchment area. These strategies tested provide options for quickly obtaining spatial information on individuals presenting at health facilities.