Does Cattle Milieu Provide a Potential Point to Target Wild Exophilic<i>Anopheles arabiensis</i>(Diptera: Culicidae) with Entomopathogenic Fungus? A Bioinsecticide Zooprophylaxis Strategy for Vector Control

Lyimo, Issa N.; Ng’habi, Kija; Mpingwa, Monica W.; Daraja, Ally A.; Mwasheshe, Dickson D.; Nchimbi, Nuru; Lwetoijera, Dickson W.; Mnyone, Ladslaus L.

doi:10.1155/2012/280583

Cited by 7 publications

(8 citation statements)

References 62 publications

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“…The development of eave tubes within screened compartments at the Ifakara Health Institute in Tanzania is presented here. Overnight release-recapture experiments were carried out in similar settings to those previously used, for example, to test the impact of fungal insecticide treatment and host meal source [ 13 , 18 ]. A self-sustaining mosquito population was also established in a “model village”, based on previous experience with creating such populations at IHI [ 19 – 21 ].…”

Section: Discussionmentioning

confidence: 99%

Eave tubes for malaria control in Africa: initial development and semi-field evaluations in Tanzania

Sternberg

Ng’habi

Lyimo

et al. 2016

Malar J

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BackgroundPresented here are a series of preliminary experiments evaluating “eave tubes”—a technology that combines house screening with a novel method of delivering insecticides for control of malaria mosquitoes.MethodsEave tubes were first evaluated with overnight release and recapture of mosquitoes in a screened compartment containing a hut and human sleeper. Recapture numbers were used as a proxy for overnight survival. These trials tested physical characteristics of the eave tubes (height, diameter, angle), and different active ingredients (bendiocarb, LLIN material, fungus). Eave tubes in a hut with closed eaves were also compared to an LLIN protecting a sleeper in a hut with open eaves. Eave tubes were then evaluated in a larger compartment containing a self-replicating mosquito population, vegetation, and multiple houses and cattle sheds. In this “model village”, LLINs were introduced first, followed by eave tubes and associated house modifications.ResultsInitial testing suggested that tubes placed horizontally and at eave height had the biggest impact on mosquito recapture relative to respective controls. Comparison of active ingredients suggested roughly equivalent effects from bendiocarb, LLIN material, and fungal spores (although speed of kill was slower for fungus). The impact of treated netting on recapture rates ranged from 50 to 70 % reduction relative to controls. In subsequent experiments comparing bendiocarb-treated netting in eave tubes against a standard LLIN, the effect size was smaller but the eave tubes with closed eaves performed at least as well as the LLIN with open eaves. In the model village, introducing LLINs led to an approximate 60 % reduction in larval densities and 85 % reduction in indoor catches of host-seeking mosquitoes relative to pre-intervention values. Installing eave tubes and screening further reduced larval density (93 % relative to pre intervention values) and virtually eliminated indoor host-seeking mosquitoes. When the eave tubes and screening were removed, larval and adult catches recovered to pre-eave tube levels.ConclusionsThese trials suggest that the “eave tube” package can impact overnight survival of host-seeking mosquitoes and can suppress mosquito populations, even in a complex environment. Further testing is now required to evaluate the robustness of these findings and demonstrate impact under field conditions.

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Section: Discussionmentioning

confidence: 99%

Eave tubes for malaria control in Africa: initial development and semi-field evaluations in Tanzania

Sternberg

Ng’habi

Lyimo

et al. 2016

Malar J

Self Cite

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“…The following alternative exposure methods might be used to target An . arabiensis post blood-meal: treating cow sheds (resting mosquitoes) [33], or treating eave curtains (exiting mosquitoes) [34]. Combinations within conventional interventions such as IRS might still have merit if it could be delivered in a single control measure with dual modes of action, ideally with a non-excito repellent, for insecticide resistance management.…”

Section: Discussionmentioning

confidence: 99%

Sterilising effects of pyriproxyfen on Anopheles arabiensis and its potential use in malaria control

et al. 2013

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BackgroundInsecticide resistance poses a major threat to current vector control campaigns. Insecticides with novel modes of action are therefore in high demand. Pyriproxyfen (PPF), a conventional mosquito pupacide, has a unique mode of action that also sterilises adult mosquitoes (unable to produce viable offspring) upon direct contact. However, the timing of PPF exposure in relation to when mosquitoes take a blood meal has an important impact on that sterilisation. This study investigated the relationship between different blood feeding and PPF exposure timings to determine the potential of PPF sterilisation in controlling Anopheles arabiensis.MethodsFour treatment regimens were investigated: blood fed three days before PPF exposure (A), blood fed one day before PPF exposure (B), blood fed one day after PPF exposure (C) and blood fed three days after PPF exposure (D) for their impact on egg laying (fecundity) and the production of viable offspring (fertility), while the impact of PPF exposure on mosquito survival was investigated in the absence of a blood meal. All regimens and the survival study exposed mosquitoes to PPF via the bottle assay at 3 mg AI/m2 for 30 minutes.ResultsFemale mosquitoes that blood-fed one day prior to PPF exposure (regimen B), produced no viable offspring during that gonotrophic cycle (100% reduction in fertility). All other treatments had no significant effect. The observed reductions in fecundity and fertility were caused by the retention of eggs (97% of eggs retained, i.e. produced in the ovaries but not laid, in regimen B, p = 0.0004). Some of these retained eggs were deformed in shape. PPF exposure on mosquito survival in the absence of a blood meal was found to have no effect.ConclusionsThe results presented here suggest that sterilising adult malaria vectors using PPF could form part of a malaria control strategy, taking advantage of the lack of reported resistance to PPF in mosquitoes and its unique mode of action. We propose that targeting resting mosquitoes, which are highly susceptible to PPF at low doses, is the optimal direction for developing this control tool.

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“…Beyond directly protecting their occasional human victims, mosquito-toxic insecticides may also be applied to livestock, to enable population control of zoophagic vectors and achieve greater proportional reductions of transmission where these are the preferred hosts for dominant local vectors [ 29 - 31 ], and transmission is fundamentally easier to manage because zoophagic mosquitoes are less efficient vectors of anthroponotic Plasmodium [ 16 - 19 ]. However, many important vector species in residual transmission systems, such as An.…”

Section: Introductionmentioning

confidence: 99%

Made-to-measure malaria vector control strategies: rational design based on insecticide properties and coverage of blood resources for mosquitoes

Killeen

Seyoum

Gimnig

et al. 2014

Malar J

102

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Eliminating malaria from highly endemic settings will require unprecedented levels of vector control. To suppress mosquito populations, vector control products targeting their blood hosts must attain high biological coverage of all available sources, rather than merely high demographic coverage of a targeted resource subset, such as humans while asleep indoors. Beyond defining biological coverage in a measurable way, the proportion of blood meals obtained from humans and the proportion of bites upon unprotected humans occurring indoors also suggest optimal target product profiles for delivering insecticides to humans or livestock. For vectors that feed only occasionally upon humans, preferred animal hosts may be optimal targets for mosquito-toxic insecticides, and vapour-phase insecticides optimized to maximize repellency, rather than toxicity, may be ideal for directly protecting people against indoor and outdoor exposure. However, for vectors that primarily feed upon people, repellent vapour-phase insecticides may be inferior to toxic ones and may undermine the impact of contact insecticides applied to human sleeping spaces, houses or clothing if combined in the same time and place. These concepts are also applicable to other mosquito-borne anthroponoses so that diverse target species could be simultaneously controlled with integrated vector management programmes. Measurements of these two crucial mosquito behavioural parameters should now be integrated into programmatically funded, longitudinal, national-scale entomological monitoring systems to inform selection of available technologies and investment in developing new ones.

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Does Cattle Milieu Provide a Potential Point to Target Wild ExophilicAnopheles arabiensis(Diptera: Culicidae) with Entomopathogenic Fungus? A Bioinsecticide Zooprophylaxis Strategy for Vector Control

Cited by 7 publications

References 62 publications

Eave tubes for malaria control in Africa: initial development and semi-field evaluations in Tanzania

Eave tubes for malaria control in Africa: initial development and semi-field evaluations in Tanzania

Sterilising effects of pyriproxyfen on Anopheles arabiensis and its potential use in malaria control

Made-to-measure malaria vector control strategies: rational design based on insecticide properties and coverage of blood resources for mosquitoes

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