Characterising the spatial dynamics of sympatric Aedes aegypti and Aedes albopictus populations in the Philippines

• Main Authors: Jennifer Duncombe, Fe Espino, Kristian Marollano, Aldwin Velazco, Scott A. Ritchie, Wenbiao Hu, Philip Weinstein, Archie C. A. Clements
• Format: Article
• Language: English
• Published: PAGEPress Publications 2013-11-01
• Series: Geospatial Health
• Subjects: dengue, Aedes, surveillance, control, Philippines.
• Online Access: http://www.geospatialhealth.net/index.php/gh/article/view/71

Entomological surveillance and control are essential to the management of dengue fever (DF). Hence, understanding the spatial and temporal patterns of DF vectors, <em>Aedes (Stegomyia) aegypti</em> (L.) and <em>Ae. (Stegomyia) albopictus</em> (Skuse), is paramount. In the Philippines, resources are limited and entomological surveillance and control are generally commenced during epidemics, when transmission is difficult to control. Recent improvements in spatial epidemiological tools and methods offer opportunities to explore more efficient DF surveillance and control solutions: however, there are few examples in the literature from resource-poor settings. The objectives of this study were to: (i) explore spatial patterns of <em>Aedes</em> populations and (ii) predict areas of high and low vector density to inform DF control in San Jose village, Muntinlupa city, Philippines. Fortnightly, adult female <em>Aedes </em>mosquitoes were collected from 50 double-sticky ovitraps (SOs) located in San Jose village for the period June-November 2011. Spatial clustering analysis was performed to identify high and low density clusters of <em>Ae. aegypti</em> and <em>Ae. albopictus</em> mosquitoes. Spatial autocorrelation was assessed by examination of semivariograms, and ordinary kriging was undertaken to create a smoothed surface of predicted vector density in the study area. Our results show that both <em>Ae. aegypti</em> and <em>Ae. albopictus</em> were present in San Jose village during the study period. However, one <em>Aedes</em> species was dominant in a given geographic area at a time, suggesting differing habitat preferences and interspecies competition between vectors. Density maps provide information to direct entomological control activities and advocate the development of geographically enhanced surveillance and control systems to improve DF management in the Philippines.