Field assessment of potential sugar feeding stations for disseminating bacteria in a paratransgenic approach to control malaria

Etienne Bilgo,Antoine Sanon,Seni Ilboudo,Abdoulaye Diabate,Marcelo Jacobs-Lorena,Roch K Dabiré,Amélie Vantaux

doi:10.1186/s12936-018-2516-x

Abstract

BackgroundUsing bacteria to express and deliver anti-parasite molecules in mosquitoes is among the list of genetic tools to control malaria. The introduction and spread of transgenic bacteria through wild adult mosquitoes is one of the major challenges of this strategy. In prospect of future field experiments, an open field study with blank (without bacteria) attractive sugar bait (ASB) was performed under the assumption that transgenic bacteria would be spread to all sugar fed mosquitoes.MethodsTwo types of ASB stations were developed, one with clay pots (CP) placed at mosquito resting sites and one with window entry traps (WET) placed inside inhabited houses. The ASB consisted in either glucose, honey or fruit cocktail solutions. In addition, mark-release-recapture (MRR) experiment of mosquitoes after feeding them with glucose was also conducted to check the proportion of the mosquito population that can be reached by the two ASB stations as well as its suitability to complement the ASB stations for disseminating bacteria.ResultsOverall, 88% of the mosquitoes were collected in the WET_ASB. The CP_ASB stations were much less attractive with the highest average of 82 ± 11 mosquitoes/day in the CP near the wood piles. The proportions of sugar fed mosquitoes upon ASB were low in both type of ASB stations, ~ 2% and ~ 14% in WET and CP, respectively. Honey solution was the most attractive solution compared to the glucose and the fruit cocktail solutions. The recapture rate in the MRR experiment was low: ~ 4.1% over 7 days.ConclusionThe WET_ASB looks promising to disseminate transgenic bacteria to endophilic West Africa Anopheles mosquito. However, this feeding station may not be fully effective and could be combined with the CP_ASB to also target outdoor resting mosquitoes. Overall, efforts are needed to improve the mosquito-feeding rates upon ASB.

Highlights

Using bacteria to express and deliver anti-parasite molecules in mosquitoes is among the list of genetic tools to control malaria
Performances of clay pot and window entry trap attractive sugar bait A total of 83,189 mosquitoes were collected over the 12 collection days
In prospect to develop tools for introducing and disseminating genetically modified bacteria into wild mosquitoes when the paratransgenic approach will come on age, we assessed for the first time the use of attractive sugar bait (ASB) feeding station in association with two trapping tools, the clay pots and the window entry traps, in an open field study [23, 25,26,27,28]

Summary

Introduction

Using bacteria to express and deliver anti-parasite molecules in mosquitoes is among the list of genetic tools to control malaria. The introduction and spread of transgenic bacteria through wild adult mosquitoes is one of the major challenges of this strategy. Malaria control currently relies on both the prompt diagnostic and effective treatments of malaria cases as well as vector control through insecticide-treated bed nets and indoor residual spraying [1] Both parasites and vectors have developed resistance against many commonly used drugs and insecticides threatening the. Laboratory experiments have shown that transgenic bacteria can be spread through sugar meals [14, 18, 19] offering a potential tool for their introduction in the field. No study has yet investigated how to introduce and disseminate bacteria through sugar meals in a field situation

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