Neemazal ® as a possible alternative control tool for malaria and African trypanosomiasis?

R Serge Yerbanga,Thierry Lefèvre,Jean-Baptiste Rayaisse,Jean Bosco Ouédraogo,François Hien,Philippe Solano,Karine Mouline,Roch K Dabiré,Ernest Salou,Annette Habluetzel,Amélie Vantaux

doi:10.1186/s13071-016-1538-x

Abstract

BackgroundResearch efforts to identify possible alternative control tools for malaria and African trypanosomiasis are needed. One promising approach relies on the use of traditional plant remedies with insecticidal activities.MethodsIn this study, we assessed the effect of blood treated with different doses of NeemAzal ® (NA, neem seed extract) on mosquitoes (Anopheles coluzzii) and tsetse flies (Glossina palpalis gambiensis) (i) avidity to feed on the treated blood, (ii) longevity, and (iii) behavioural responses to human and calf odours in dual-choice tests. We also gauged NeemAzal ® toxicity in mice.ResultsIn An. coluzzii, the ingestion of NA in bloodmeals offered by membrane feeding resulted in (i) primary antifeedancy; (ii) decreased longevity; and (iii) reduced response to host odours. In G. palpalis gambiensis, NA caused (i) a knock-down effect; (ii) decreased or increased longevity depending on the dose; and (iii) reduced response to host stimuli. In both cases, NA did not affect the anthropophilic rate of activated insects. Overall, the most significant effects were observed with NA treated bloodmeals at a dose of 2000 μg/ml for mosquitoes and 50 μg/ml for tsetse flies. Although no mortality in mice was observed after 14 days of follow-up at oral doses of 3.8, 5.6, 8.4 and 12.7 g/kg, behavioural alterations were noticed at doses above 8 g/kg.ConclusionThis study revealed promising activity of NA on A. coluzzii and G. palpalis gambiensis but additional research is needed to assess field efficacy of neem products to be possibly integrated in vector control programmes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1538-x) contains supplementary material, which is available to authorized users.

Highlights

Research efforts to identify possible alternative control tools for malaria and African trypanosomiasis are needed
Using the mosquito Anopheles coluzzii, a major vector of P. falciparum, and the tsetse fly Glossina palpalis gambiensis, an important vector of African animal and human trypanosomes, the current study determined the effect of blood treated with NeemAzal ® at different doses on (i) the avidity to feed on the treated blood; (ii) longevity of the insects; and (iii) their behavioural responses to human and calf odours in dual-choice tests
Flies fed on blood supplemented with a concentration of 2000 μg/ml of NeemAzal ® (NA) displayed slightly higher scores than flies fed on the other NA treatments

Summary

Introduction

Research efforts to identify possible alternative control tools for malaria and African trypanosomiasis are needed. Malaria and human African trypanosomiasis are among the most important vector-borne diseases. There is a need to develop on complementary novel strategies for the control of the parasitic diseases, ideally based on “active ingredients” readily available in these countries such as neem. As part of this effort, a ‘One Health’ approach is increasingly recognized to be key to effective and sustainable control of vector-borne diseases [14], especially for those exploiting the intimate livestock-man interface such as African trypanosomiasis

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