Sterile Insect Technique: Successful Suppression of an Aedes aegypti Field Population in Cuba

SIMPLE SUMMARY: The sterile insect technique (SIT) is a species-specific and environment-friendly method of insect control that relies on the release of large numbers of sterile insects. Mating released sterile males with wild females leads to a decrease in the reproductive potential and to the local suppression of the target population. There is increased interest in applying this approach to manage disease-transmitting mosquito populations. The main focus of this pilot trial was to assess the efficacy of the SIT for the suppression of Aedes aegypti populations. Two areas in Havana city, Cuba, were selected as control and release trial sites. The presence, density and fertility of the target wild population were monitored through a network of ovitraps. Approximately 1,270,000 irradiated Ae. aegypti males were released in the 50 ha target area over a period of 20 weeks. The released mosquitoes showed excellent mating competitiveness and induced high levels of sterility in the wild Ae. aegypti population. The target natural population was suppressed as reflected in the ovitrap index and in the mean number of eggs/trap values which dropped to zero by the last 3 weeks of the trial. We conclude that the released sterile male Ae. aegypti competed successfully and induced significant sterility in the local target Ae. aegypti population, resulting in suppression of the vector. ABSTRACT: Dengue virus infections are a serious public health problem worldwide. Aedes aegypti is the primary vector of dengue in Cuba. As there is no vaccine or specific treatment, the control efforts are directed to the reduction of mosquito populations. The indiscriminate use of insecticides can lead to adverse effects on ecosystems, including human health. The sterile insect technique is a species-specific and environment-friendly method of insect population control based on the release of large numbers of sterile insects, ideally males only. The success of this technique for the sustainable management of agricultural pests has encouraged its evaluation for the population suppression of mosquito vector species. Here, we describe an open field trial to evaluate the effect of the release of irradiated male Ae. aegypti on a wild population. The pilot trial was carried out in a suburb of Havana and compared the mosquito population density before and after the intervention, in both untreated control and release areas. The wild population was monitored by an ovitrap network, recording frequency and density of eggs as well as their hatch rate. A significant amount of sterility was induced in the field population of the release area, as compared with the untreated control area. The ovitrap index and the mean number of eggs/trap declined dramatically after 12 and 5 weeks of releases, respectively. For the last 3 weeks, no eggs were collected in the treatment area, clearly indicating a significant suppression of the wild target population. We conclude that the sterile males released competed successfully and induced enough sterility to suppress the local Ae. aegypti population.