Applicability of the Mexican Ovitrap System for Aedes Vector Surveillance in Los Patios, Colombia

Abstract Background: Vector surveillance has been ongoing since the 1960’s through larval surveys, which are not useful to serve as an alarm indicator for outbreak prediction since they are usually done in an unsystematic way. This can be achieved with the ovitrap system. This study aimed to determine the feasibility, required resources and costs of installing and maintaining an ovitrap vector surveillance system in a municipality of Colombia.Methods: The study applied a cross sectional design including the mapping of target houses, implementation of the ovitrap system (following the Mexican ovitrap model) and an analysis of resource requirements. The mapping was done using street maps from Google Earth. 40 ovitraps were manufactured and installed on 10 blocks (1 ovitrap on each side of every cardinal point of the block, every third block), and revised weekly by two vector control technicians for a four-week period. Personal interviews with the technicians regarding costs of daily income, transport needs of human resources and requirement of equipment for manufacturing and maintaining the ovitraps, were conducted for the cost analysis. Results: A map of the 40 ovitrap geolocations facilitated the implementation. Entomological findings were expressed with six indicators. These were (results in brackets): Process indicators: Percent of acceptance by houseowners (76.9%), Percent of relocation of traps (5%), Percent of ovitraps examined in 4 study weeks (97.5%, 97.5%, 97.5%, 100%), Percent of intact ovitraps (92.5%, 97.5%, 97.5%, 100%). Result indicators: Percent of positive ovitraps (80%, 90%, 75%, 97.5%), Percent of positive blocks (100%). Operational indicators: Time for the installation of 40 ovitraps (10h15m), time for the weekly reading and reinstallation (7h40m, 7h15m, 7h53m, 7h), Time for data transmission to the operational centre (8h, 4h, 2h, 2h). Cost of installing and reviewing 40 ovitraps during four weeks: COL$1,142,304.47 or US$297. Projection of costs for covering the entire municipality of Los Patios (95000 inhabitants) with 348 ovitraps in one year: COL$24,631,329.27 or US$6,404.14. Conclusions: The implementation of the ovitrap system is feasible and affordable in Colombian municipalities and other endemic areas since most of the costs are already covered by the vector control services (salaries and transport).