Field experiments of Anopheles gambiae attraction to local fruits/seedpods and flowering plants in Mali to optimize strategies for malaria vector control in Africa using attractive toxic sugar bait methods

<p>Abstract</p> <p>Background</p> <p>Based on recent studies in Israel demonstrating that attractive toxic sugar bait (ATSB) methods can be used to decimate local anopheline and culicine mosquito populations, an important consideration is whether the same methods can be adapted and improved to attract and kill malaria vectors in Africa. The ATSB approach uses fruit or flower scent as an attractant, sugar solution as a feeding stimulant, and an oral toxin. The ATSB solutions are either sprayed on vegetation or suspended in simple bait stations, and the mosquitoes ingesting the toxic solutions are killed. As such, this approach targets sugar-feeding female and male mosquitoes. This study examines the attractiveness of African malaria vectors to local fruits/seedpods and flowering plants, key biological elements of the ATSB approach for mosquito control.</p> <p>Methods</p> <p>Three field experiments were conducted at sites in Mali. The attraction of <it>Anopheles gambiae </it>s.l. to 26 different local fruits and seedpods was determined at a site in the semi-arid Bandiagara District of Mali. Wire mesh glue traps with fruits/seedpods suspended on skewers inside were set along a seasonal lagoon. Seven replicates of each fruit/seedpod species were tested, with a water-soaked sponge and a sugar-soaked sponge as controls. The attraction of <it>An. gambiae </it>s.l. to 26 different types of flowering plants was determined at a site near Mopti in Mali. The flowering plants held in a water-filled buried container were tested using the same glue traps, with controls including water only and sugar solution. Six replicates of each selected plant type were tested on transects between rice paddies. Additional studies using CDC light traps were done to determine the relative densities and periodicity of <it>An. gambiae </it>s.l. attraction to branches of the most highly attractive flowering plant, branches without flowers, human odor, and candescent light.</p> <p>Results</p> <p>Of the 26 fruits and seedpods tested, 6 were attractive to <it>An. gambiae </it>s.l. females and males, respectively. Guava (<it>Psidium guajava</it>) and honey melon (<it>Cucumis melo</it>) were the two most attractive fruits for both females and males. Of the 26 flowering plants tested, 9 were significantly attractive for females, and 8 were attractive for males. <it>Acacia macrostachya </it>was the most attractive flowering plant. Periodicity studies using this plant showed peaks of <it>An. gambiae </it>s.l. attraction between 1930 and 2200 h and 0400-0500 h, which differed considerably from the response to human odors, which expectedly peaked at around midnight.</p> <p>Conclusion</p> <p>These field experiments in Mali highlight that female and male <it>An. gambiae </it>s.l. have pronounced differences in attraction for diverse types of indigenous fruits/seedpods and flowering plants. The identification of attractive fruits and seedpods shows that a variety of indigenous and locally abundant natural products could potentially be used as juices to make ATSB solution for mosquito control. As well, the simple methods used to identify the most attractive flowering plants provide valuable insights into the natural history of sugar feeding for <it>An. gambiae </it>s.l. These observations can be used to guide future strategies for employing ATSB methods for malaria vector control in Africa. They also provide a basis for subsequent chemical analysis and development of attractive baits for mosquito control.</p

Seven new species of Rhynchobombyx Aurivillius, 1909 from Congolian lowland forests (Lepidoptera: Lasiocampidae)

Seven new species of the Afrotropic Lasiocampidae genus Rhynchobombyx are described and illustrated: Rh. gavinfilippone Prozorov, Saldaitis & Müller sp. n., Rh. avadomenicarocchio Prozorov, Saldaitis & Müller sp. n., Rh. julianjameseaton Prozorov, Saldaitis & Müller sp. n., Rh. anthonychristophereaton Prozorov, Saldaitis & Müller sp. n., Rh. nicolasroberteaton Prozorov, Saldaitis & Müller sp. n., Rh. arijakefriend Prozorov, Saldaitis & Müller sp. n., Rh. madisonellafriend Prozorov, Saldaitis & Müller sp. n. All species originate from the poorly studied Congolian lowland forests ecoregion of Congo and Democratic Republic of the Congo. Lectotype and paralectotype of Rh. nasuta Aurivillius, 1909 are designated here, the species type locality is specified

Application of time-lapse camera situated near a light source, for registration insects’ rhythm of attraction to light (Lepidoptera: Noctuidae)

Camera traps are an efficient means of biodiversity assessments. however, the employment of camera traps for the study of insects is still in its beginning. Accurate counting and recognition of flying insects are also of great importance in pest control. In this paper, we present a new method combining a time-lapse camera, and a light source, designed to estimate macro-Lepidoptera species composition, occurrence and also daily rhythms of their attraction to light. The advantage of the system is that it enables to monitor the species assemblages distantly. The rhythms to light attraction discussed for six Noctuidae species

Perspectives of people in Mali toward genetically-modified mosquitoes for malaria control

Background: Genetically-modified (GM) mosquitoes have been proposed as part of an integrated vector control strategy for malaria control. Public acceptance is essential prior to field trials, particularly since mosquitoes are a vector of human disease and genetically modified organisms (GMOs) face strong scepticism in developed and developing nations. Despite this, in sub-Saharan Africa, where the GM mosquito effort is primarily directed, very little data is available on perspectives to GMOs. Here, results are presented of a qualitative survey of public attitudes to GM mosquitoes for malaria control in rural and urban areas of Mali, West Africa between the months of October 2008 and June 2009. Methods: The sample consisted of 80 individuals - 30 living in rural communities, 30 living in urban suburbs of Bamako, and 20 Western-trained and traditional health professionals working in Bamako and Bandiagara. Questions were asked about the cause of malaria, heredity and selective breeding. This led to questions about genetic alterations, and acceptable conditions for a release of pest-resistant GM corn and malaria-refractory GM mosquitoes. Finally, participants were asked about the decision-making process in their community. Interviews were transcribed and responses were categorized according to general themes. Results: Most participants cited mosquitoes as one of several causes of malaria. The concept of the gene was not widely understood; however selective breeding was understood, allowing limited communication of the concept of genetic modification. Participants were open to a release of pest-resistant GM corn, often wanting to conduct a trial themselves. The concept of a trial was reapplied to GM mosquitoes, although less frequently. Participants wanted to see evidence that GM mosquitoes can reduce malaria prevalence without negative consequences for human health and the environment. For several participants, a mosquito control programme was preferred; however a transgenic release that satisfied certain requirements was usually acceptable. Conclusions: Although there were some dissenters, the majority of participants were pragmatic towards a release of GM mosquitoes. An array of social and cultural issues associated with malaria, mosquitoes and genetic engineering became apparent. If these can be successfully addressed, then social acceptance among the populations surveyed seems promising

Successful field trial of attractive toxic sugar bait (ATSB) plant-spraying methods against malaria vectors in the Anopheles gambiae complex in Mali, West Africa

<p>Abstract</p> <p>Background</p> <p>Based on highly successful demonstrations in Israel that attractive toxic sugar bait (ATSB) methods can decimate local populations of mosquitoes, this study determined the effectiveness of ATSB methods for malaria vector control in the semi-arid Bandiagara District of Mali, West Africa.</p> <p>Methods</p> <p>Control and treatment sites, selected along a road that connects villages, contained man-made ponds that were the primary larval habitats of <it>Anopheles gambiae </it>and <it>Anopheles arabiensis</it>. Guava and honey melons, two local fruits shown to be attractive to <it>An. gambiae </it>s.l., were used to prepare solutions of Attractive Sugar Bait (ASB) and ATSB that additionally contained boric acid as an oral insecticide. Both included a color dye marker to facilitate determination of mosquitoes feeding on the solutions. The trial was conducted over a 38-day period, using CDC light traps to monitor mosquito populations. On day 8, ASB solution in the control site and ATSB solution in the treatment site were sprayed using a hand-pump on patches of vegetation. Samples of female mosquitoes were age-graded to determine the impact of ATSB treatment on vector longevity.</p> <p>Results</p> <p>Immediately after spraying ATSB in the treatment site, the relative abundance of female and male <it>An. gambiae </it>s.l. declined about 90% from pre-treatment levels and remained low. In the treatment site, most females remaining after ATSB treatment had not completed a single gonotrophic cycle, and only 6% had completed three or more gonotrophic cycles compared with 37% pre-treatment. In the control site sprayed with ASB (without toxin), the proportion of females completing three or more gonotrophic cycles increased from 28.5% pre-treatment to 47.5% post-treatment. In the control site, detection of dye marker in over half of the females and males provided direct evidence that the mosquitoes were feeding on the sprayed solutions.</p> <p>Conclusion</p> <p>This study in Mali shows that even a single application of ATSB can substantially decrease malaria vector population densities and longevity. It is likely that ATSB methods can be used as a new powerful tool for the control of malaria vectors, particularly since this approach is highly effective for mosquito control, technologically simple, inexpensive, and environmentally safe.</p

Stock identification: advancing in the knowledge of stock structure as a requirement for stock assessment

DEMERSTEM- Objectives of WP 1: -Improve the knowledge on the selected demersal stocks with a particular effort to solve the problems of stock identification and improvement of the quality of the data used for the assessment. -This follows the recommendations regularly made by CECAF.Peer reviewe