Exploring Spatial and Temporal Distribution of Cutaneous Leishmaniasis in the Americas, 2001-2011

Leishmaniasis is an important health problem in several countries in the Americas and cases notification is limited and underreported. In 2008, the Pan American Health Organization (PAHO/WHO) met with endemic countries to discuss the status and need of improvement of systems region-wide. The objective is to describe the temporal and spatial distribution of cutaneous leishmaniasis (CL) cases reported to PAHO/WHO by the endemic countries between 2001 and 2011 in the Americas. Methods Cases reported in the period of 2001–2011 from 14/18 CL endemic countries were included in this study by using two spreadsheet to collect the data. Two indicators were analyzed: CL cases and incidence rate. The local regression method was used to analyze case trends and incidence rates for all the studied period, and for 2011 the spatial distribution of each indicator was analyzed by quartile and stratified into four groups. Results From 2001–2011, 636,683 CL cases were reported by 14 countries and with an increase of 30% of the reported cases. The average incidence rate in the Americas was 15.89/100,000 inhabitants. In 2011, 15 countries reported cases in 180 from a total of 292 units of first subnational level. The global incidence rate for all countries was 17.42 cases per 100,000 inhabitants; while in 180 administrative units at the first subnational level, the average incidence rate was 57.52/100,000 inhabitants. Nicaragua and Panama had the highest incidence but more cases occurred in Brazil and Colombia. Spatial distribution was heterogeneous for each indicator, and when analyzed in different administrative level. The results showed different distribution patterns, illustrating the limitation of the use of individual indicators and the need to classify higher-risk areas in order to prioritize the actions. This study shows the epidemiological patterns using secondary data and the importance of using multiple indicators to define and characterize smaller territorial units for surveillance and control of leishmaniasis.
Author Summary In the Americas, cutaneous leishmaniasis (CL) cases are notified across a wide geographic area, extending from southern United States to northern Argentina. Currently, 70–75% of all estimated cases of CL worldwide occur in ten countries, including four in the Americas (Brazil, Colombia, Nicaragua, and Peru) and six countries from Africa and the Eastern Mediterranean. This study shows the epidemiological situation and geographical distribution of CL cases reported by passive surveillance system of endemic countries of the American Region from 2001 to 2011, collected and consolidated by the Pan American Health Organization (PAHO). Furthermore, it represents a joint effort of the National Programs of leishmaniases. Despite some limitations, the data were analyzed and discussed and this study represents the first step to understand the global epidemiological situation in this Region and it contributes to the improvement of the surveillance of leishmaniases in the Americas.