RESUMO
BACKGROUND: Despite the identification of some environmental factors linked to the cutaneous leishmaniasis (CL) epidemic, little is known about the impact of environmental disturbances caused by human activities. We assessed the association between socioeconomic and demographic factors with the spatial structure of the CL epidemic in Colombia. METHODS: Using data from more than 65 000 CL cases collected across the entire country from publicly available sources, we conducted a spatial clustering analysis to identify high burden areas (clusters) of CL. Associations between CL clusters and socioeconomic variables were investigated. RESULTS: We identified seven statistically significant clusters of CL located across all Colombian biomes. Deforestation and livestock were statistically significantly associated with the spatial clustering of CL. Urbanization, time spent traveling to main cities and water bodies were other factors linked with the clustering of CL. CONCLUSIONS: This study found that human activities such as deforestation linked to agriculture, livestock production and mining activities are key drivers of the spatial distribution of the CL epidemic. The intensity of these human activities, which are projected to increase because of social and economic transformations in progress in Colombia, will potentially exacerbate the already growing CL epidemic in the country.
RESUMO
Background: Cutaneous leishmaniasis (CL) is a vector-borne disease that is widely distributed in most tropical regions. Colombia has experienced an important increase in its incidence during the last decade. There are CL transmission foci in the Colombian departments of Santander and Norte de Santander. Objectives: To identify environmental and socio-economic variables associated with CL incidence in the municipalities of the northeast of Colombia between 2007 and 2016. Methods: This was an ecological study of CL cases aggregated by municipality. The cases reported during the study period were analyzed with a negative binomial regression to obtain the adjusted incident rate ratio for environmental and socio-economic variables. Findings: During the study period, 10 924 cases of CL were reported, and 110 (86.6%) municipalities reported at least one CL case. The coverages of forest (aIRR 1.05, 95% CI 1.03-1.07), heterogeneous agricultural zones (aIRR 1.04, 95% CI 1.02-1.06) and permanent crops (aIRR 1.07, 95% CI 1.02-1.12) were associated with a higher incidence of CL. Conversely, urban functionality (aIRR 0.95, 95% CI 0.92-0.96), minimal-altitude above sea level (aIRR 0.84, 95% CI 0.79-0.90) and shrub coverage (aIRR 0.98, 95% CI 0.95-1.0) were negatively associated with the incidence of CL in the municipality. Main conclusions: Our results confirm the importance of environmental determinants, such as height above sea level, and coverage of forest, permanent crops and heterogeneous agricultural zones, for the occurrence of CL; these findings also suggest the importance of shrub coverage. Furthermore, urban functionality was a socio-economic determinant independently associated with CL incidence.