Development and evaluation of a novel contamination device that targets multiple life-stages of Aedes aegypti

Abstract

BackgroundThe increasing global threat of Dengue demands new and easily applicable vector control methods. Ovitraps provide a low-tech and inexpensive means to combat Dengue vectors. Here we describe the development and optimization process of a novel contamination device that targets multiple life-stages of the Aedes aegypti mosquito. Special focus is directed to the diverse array of control agents deployed in this trap, covering adulticidal, larvicidal and autodissemination impacts.MethodsDifferent trap prototypes and their parts are described, including a floater to contaminate alighting gravid mosquitoes. The attractiveness of the trap, different odor lures and floater design were studied using fluorescent powder adhering to mosquito legs and via choice tests. We demonstrate the mosquitocidal impacts of the control agents: a combination of the larvicide pyriproxyfen and the adulticidal fungus Beauveria bassiana. The impact of pyriproxyfen was determined in free-flight dissemination experiments. The effect on larval development inside the trap and in surrounding breeding sites was measured, as well as survival impacts on recaptured adults.ResultsThe developmental process resulted in a design that consists of a black 3 Liter water-filled container with a ring-shaped floater supporting vertically placed gauze dusted with the control agents. On average, 90% of the mosquitoes in the fluorescence experiments made contact with the gauze on the floater. Studies on attractants indicated that a yeast-containing tablet was the most attractive odor lure. Furthermore, the fungus Beauveria bassiana was able to significantly increase mortality of the free-flying adults compared to controls. Dissemination of pyriproxyfen led to >90% larval mortality in alternative breeding sites and 100% larval mortality in the trap itself, against a control mortality of around 5%.ConclusionThis ovitrap is a promising new tool in the battle against Dengue. It has proven to be attractive to Aedes aegypti mosquitoes and effective in contaminating these with Beauveria bassiana. Furthermore, we show that the larvicide pyriproxyfen is successfully disseminated to breeding sites close to the trap. Its low production and operating costs enable large scale deployment in Dengue-affected locations.

Electrostatic coating enhances bioavailability of insecticides and breaks pyrethroid resistance in mosquitoes

“…Previous studies show that it can be used effectively to apply novel and biological control agents such as entomopathogens and autodisseminants. Experiments with Beauveria bassiana spores and pyriproxyfen applied on electrostatic netting inside a novel Aedes ovitrap showed that effective doses of these agents were transferred to gravid aedine mosquitoes, inducing high fungus infection rates and successful larvicide dissemination (36). Electrostatic netting thus can provide a means to apply and deploy novel insecticides currently under development (16), which can further assist in the management of insecticide resistance.…”

“…Electrostatic netting can be useful for house-screening products and point-source applications such as mosquito traps (36). The use of electrostatic netting placed at the eave level of rural houses in Tanzania is currently being investigated.…”

Control methods against invasive Aedes mosquitoes in Europe: a review

“…Although spray applications, particularly at ULV, have been successfully used in some integrated IMS control campaigns against Aedes mosquitoes, this method is debatable because of high costs, slow operational response, low community acceptance, ineffective time of application, rather low efficacy and/or residual effects and potential impact on non‐target species . Furthermore, the development of insecticide resistance in Aedes populations remains a challenge for vector control . In Brazil, pyrethroid resistance levels in Ae.…”

“…124,135,136 Furthermore, the development of insecticide resistance in Aedes populations remains a challenge for vector control. 121,131,137 In Brazil, pyrethroid resistance levels in Ae. aegypti populations increased rapidly after an integrated IMS control campaign including ULV ground spraying of 2% deltamethrin.…”

Effectiveness of autodissemination stations containing pyriproxyfen in reducing immature Aedes albopictus populations

“…A novel ovitrap was developed based on pull and push strategy to control Ae. aegypti by Snetselar et al [28], using a combination of attractant media, Beauveria bassina (an entomopathogenic fungi), and pyriproxyfen (a biopesticide). Researchers achieved 100% larval mortality in the laboratory; however, the study did not include any field trials.…”