Current status of spatial repellents in the global vector control community

2022 ◽  
pp. 267-278
Author(s):  
Nicole L. Achee ◽  
John P. Grieco
2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Betelehem Wondwosen ◽  
Mengistu Dawit ◽  
Yared Debebe ◽  
Habte Tekie ◽  
Sharon R. Hill ◽  
...  

Abstract Background Odour-based tools targeting gravid malaria vectors may complement existing intervention strategies. Anopheles arabiensis are attracted to, and stimulated to oviposit by, natural and synthetic odours of wild and domesticated grasses associated with mosquito breeding sites. While such synthetic odour lures may be used for vector control, these may have limited efficacy when placed in direct competition with the natural source. In this study, workflows developed for plant-feeding pests was used to design and evaluate a chimeric odour blend based on shared attractive compounds found in domesticated grass odours. Methods Variants of a synthetic odour blend, composed of shared bioactive compounds previously identified in domesticated grasses, was evaluated sequentially in a two-choice olfactometer to identify a ratio-optimized attractive blend for malaria vectors. During this process, blends with ratios that were significantly more attractive than the previously identified synthetic rice blend were compared to determine which was most attractive in the two-choice olfactometer. To determine whether all volatile components of the most attractive blend were necessary for maximal attraction, subtractive assays were then conducted, in which individual components were removed for the most attractive blend, to define the final composition of the chimeric blend. Binary logistic regression models were used to determine significance in all two-choice assays. The chimeric blend was then assessed under field conditions in malaria endemic villages in Ethiopia, to assess the effect of dose, trap type, and placement relative to ground level. Field data were analyzed both descriptively and using a Welch-corrected t-test. Results A ratio-optimized chimeric blend was identified that significantly attracted gravid An. arabiensis under laboratory conditions. In the field, trap captures of An. arabiensis and Anopheles pharoensis were dependent on the presence of the lure, trap type (CDC, BG Sentinel and Suna traps), placement relevant to ground level, with low release rates generally luring more mosquitoes. Conclusions The workflow designed for the development of chimeric lures provides an innovative strategy to target odour-mediated behaviours. The chimeric lure identified here can be used in existing trapping systems, and be customized to increase sustainability, in line with goals of the Global Vector Control Response Group.


Author(s):  
Willem Takken ◽  
Constantianus JM Koenraadt ◽  
Jeroen Spitzen ◽  
Raman Velayudhan

2019 ◽  
Vol 35 (4) ◽  
pp. 267-270 ◽  
Author(s):  
Gregor J. Devine ◽  
Hans J. Overgaard ◽  
Richard E. Paul
Keyword(s):  

2020 ◽  
Vol 14 (8) ◽  
pp. e0008606 ◽  
Author(s):  
Frederik Seelig ◽  
Haroldo Bezerra ◽  
Mary Cameron ◽  
Jeffrey Hii ◽  
Alexandra Hiscox ◽  
...  
Keyword(s):  

Author(s):  
F. Schaffner ◽  
D. Bansal ◽  
K. Mardini ◽  
S.A. Al-Marri ◽  
M.H.J. Al-Thani ◽  
...  

Vector-borne diseases (VBDs) have re-emerged worldwide due to urbanisation, increase in travel and climate change, becoming a major and serious threat to global public health. In Qatar, the concern has recently risen because of the attribution of the soccer 2022 FIFA World Cup Qatar™, which necessitates fulfilling requirements in terms of prevention and preparedness for disease transmission, including VBDs. This review presents a general overview about current status of vectors and VBDs in Qatar and addresses key challenges and future prospects of control programmes and strategies. It is based on a vector control situation analysis and needs assessment performed during an expert mission in Qatar, November 2017, organised by the WHO Eastern Mediterranean Regional Office and achieved in collaboration with the Ministry of Public Health of Qatar and other local stakeholders. The situation of vectors and VBDs of public health importance in Qatar was analysed based on a systematic literature review by December 31, 2019. The literature reveals that no locally transmitted VBD cases have been recorded in Qatar, but cases were recorded among expatriate workers and travellers who returned from an endemic country. However, data on VBD cases remain scarce except for malaria. The presence of native arthropod vectors is under-recorded to date. A compilation of literature data revealed reports of 30 vector species, including 20 mosquitoes, 2 fleas, 1 louse, 1 fly, and 6 ticks. Overall, Qatar benefits currently from a good surveillance of some VBDs (malaria) and has some capacities in vector control, but no national plan exists, and vector surveillance is in its infancy. In Qatar, clear needs exist in capacity in epidemiology and vector entomology, as well as on the organisational level, and a number of measures are suggested to mitigate and improve VBD risk assessment and management. There is an urgent need to define sustainable solutions for VBD control, management and prevention, and a number of recommendations are suggested.


F1000Research ◽  
2022 ◽  
Vol 10 ◽  
pp. 200
Author(s):  
Dewi Susanna ◽  
Dian Pratiwi

Background: The application of insecticides for malaria vector control has led to a global problem, which is the current trend of increased resistance against these chemicals. This study aimed to review the insecticide resistance status was previously determined in Asia and how to implement the necessary interventions. Moreover, the implications of resistance in malaria vector control in this region were studied. Methods: This systematic review was conducted using a predefined protocol based on PRISMA-retrieved articles from four science databases, namely ProQuest, Science Direct, EBSCO, and PubMed in the last ten years (2009 to 2019). The searching process utilized four main combinations of the following keywords: malaria, vector control, insecticide, and Asia. In ProQuest, malaria control, as well as an insecticide, were used as keywords. The following criteria were included in the filter, namely full text, the source of each article, scholarly journal, Asia, and publication date as in the last ten years. Results: There were 1408 articles retrieved during the initial search (ProQuest=722, Science Direct=267, EBSCO=50, PubMed=285, and Scopus=84). During the screening, 27 articles were excluded because of duplication, 1361 based on title and abstract incompatibility with the inclusion criteria, and 20 due to content differences. In the final screening process, 15 articles were chosen to be analyzed. From the 15 articles, it is known that there was organochlorine (DDT), organophosphate (malathion), and pyrethroids resistance in several Anopheles species with a less than 80% mortality rate. Conclusion: This review found multiple resistance in several Anopheles includes resistance to pyrethroid. The reports of pyrethroid resistance were quite challenging because it is considered effective in the malaria vector control. Several countries in Asia are implementing an insecticide resistance management (IRM) strategy against malaria vectors following the Global Plan for IRM.


Author(s):  
Constantianus J.M. Koenraadt ◽  
Raman Velayudhan ◽  
Jeroen Spitzen ◽  
Willem Takken

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Adrian Denz ◽  
Margaret M. Njoroge ◽  
Mgeni M. Tambwe ◽  
Clara Champagne ◽  
Fredros Okumu ◽  
...  

Abstract Background Semi-field experiments with human landing catch (HLC) measure as the outcome are an important step in the development of novel vector control interventions against outdoor transmission of malaria since they provide good estimates of personal protection. However, it is often infeasible to determine whether the reduction in HLC counts is due to mosquito mortality or repellency, especially considering that spatial repellents based on volatile pyrethroids might induce both. Due to the vastly different impact of repellency and mortality on transmission, the community-level impact of spatial repellents can not be estimated from such semi-field experiments. Methods We present a new stochastic model that is able to estimate for any product inhibiting outdoor biting, its repelling effect versus its killing and disarming (preventing host-seeking until the next night) effects, based only on time-stratified HLC data from controlled semi-field experiments. For parameter inference, a Bayesian hierarchical model is used to account for nightly variation of semi-field experimental conditions. We estimate the impact of the products on the vectorial capacity of the given Anopheles species using an existing mathematical model. With this methodology, we analysed data from recent semi-field studies in Kenya and Tanzania on the impact of transfluthrin-treated eave ribbons, the odour-baited Suna trap and their combination (push–pull system) on HLC of Anopheles arabiensis in the peridomestic area. Results Complementing previous analyses of personal protection, we found that the transfluthrin-treated eave ribbons act mainly by killing or disarming mosquitoes. Depending on the actual ratio of disarming versus killing, the vectorial capacity of An. arabiensis is reduced by 41 to 96% at 70% coverage with the transfluthrin-treated eave ribbons and by 38 to 82% at the same coverage with the push–pull system, under the assumption of a similar impact on biting indoors compared to outdoors. Conclusions The results of this analysis of semi-field data suggest that transfluthrin-treated eave ribbons are a promising tool against malaria transmission by An. arabiensis in the peridomestic area, since they provide both personal and community protection. Our modelling framework can estimate the community-level impact of any tool intervening during the mosquito host-seeking state using data from only semi-field experiments with time-stratified HLC.


2021 ◽  
Vol 4 ◽  
pp. 109
Author(s):  
Guilherme B. Costa ◽  
Ruth Smithyman ◽  
Scott L. O'Neill ◽  
Luciano A. Moreira

One of the pillars of the World Health Organization’s (WHO) Global Vector Control Response 2017–2030 strategy is the engagement of communities. Among the priority activities, defined by 2022 by the WHO, is the development of plans for the effective engagement and mobilisation of communities in vector control. Novel technologies for arboviruses control are being developed, such as the Wolbachia method, implemented by the World Mosquito Program (WMP). Here we discuss and analyse the framework for community engagement implemented by the WMP in Brazil, during the large-scale deployment of the method in the municipalities of Niterói and Rio de Janeiro, Brazil. Our experience indicates that the community engagement work for arboviruses control should be understood as an opportunity for local development. It is necessary, based on an integrated analysis of the territory, to understand that the actions for arboviruses control could be a catalyst for the necessary socioenvironmental, cultural and public health changes. Furthermore, it is essential to understand that community engagement goes beyond informing or asking for population consent, but it constitutes a possibility for dialogue and exchange between the various stakeholders present in the territories, to build on cooperation for mosquito-borne disease control.


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