Operationalized releases ofwAlbBWolbachiainAedes aegyptilead to sharp decreases in dengue incidence dependent onWolbachiafrequency

Abstract

AbstractInAedes aegyptimosquitoes, introduction of certain strains of inheritedWolbachiasymbionts results in transmission blocking of various viruses of public health importance, including dengue. This has resulted in a ‘replacement’ strategy for dengue control involving release of male and female mosquitoes, whereuponWolbachiais able to spread throughAe. aegyptipopulations to high frequency and reduces the incidence of dengue.WolbachiastrainwAlbB is an effective transmission blocker and stable at high temperatures, making it very suitable for use in hot tropical climates. Following the first trial field releases of thewAlbB strain inAe. aegyptiin Malaysia, releases ofwAlbBAe. aegyptihave for the first time become operationalized by the Malaysian health authorities. We report here on changes in dengue incidence based on a set of 20 releases sites and 76 control sites in high rise residential areas, which allows us to directly assess the impact ofWolbachiafrequency on dengue incidence. The results indicate an average reduction in dengue of 62.4% (confidence intervals 50-71%); importantly the level of suppression increased withWolbachiafrequency, with suppression of 75.8% (confidence intervals 61-87%) estimated at 100%Wolbachiafrequency. These findings emphasize the large impacts ofwAlbBWolbachiainvasions on dengue incidence in an operational setting, with the expectation that the level of dengue will further decrease as wider areas are invaded.