Efficacy of a Spatial Repellent for Control of Malaria in Indonesia: A Cluster-Randomized Controlled Trial

Syafruddin, Din; Rozi, Ismail Ekoprayitno; Permana, Dendi Hadi; Hidayati, Anggi Puspa Nur; Syahrani, Lepa; Zubaidah, Siti; Sidik, Dian; Bangs, Michael J.; Bøgh, Claus; Liu, Fang; Eugenio, Evercita C.; Hendrickson, Jared; Burton, Timothy A.; Baird, J. Kevin; Collins, Frank H.; Grieco, John P.; Lobo, Neil F.; Achee, Nicole L.

doi:10.4269/ajtmh.19-0554

Cited by 63 publications

(89 citation statements)

References 49 publications

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“…It contains transfluthrin, a volatile pyrethroid chemical currently used in household mosquito control product such as coils. Preliminary findings of a robust cluster randomized, double-blinded placebo-controlled trial in Indonesia suggests protective effects of the SR product evaluated in this study [17].…”

Section: Sr Productmentioning

confidence: 66%

“…Studies in Africa have shown that increasing knowledge and awareness of vector control tools may increase the uptake of novel malaria control interventions [16,17]. Repellent products such as mosquito coils, topical repellent creams and spatial repellent emanators have been proven effective to protect against malaria [18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

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Knowledge, attitudes and practices assessment of malaria interventions in rural Zambia

et al. 2020

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Background: Despite rapid upscale of insecticide-treated nets (ITNs) and indoor residual spraying (IRS), malaria remains a major source of morbidity and mortality in Zambia. Uptake and utilization of these and novel interventions are often affected by knowledge, attitudes and practices (KAP) amongst persons living in malariaendemic areas. The aims of this study were to assess malaria KAP of primary caregivers and explore trends in relation to ITN use, IRS acceptance and mosquito density in two endemic communities in Luangwa and Nyimba districts, Zambia. Methods: A cohort of 75 primary caregivers were assessed using a cross-sectional, forced-choice malaria KAP survey on ITN use, IRS acceptance and initial perception of a novel spatial repellent (SR) product under investigation. Entomological sampling was performed in participant homes using CDC Miniature Light Traps to relate indoor mosquito density with participant responses. Results: Ninety-nine percent of participants cited bites of infected mosquitoes as the route of malaria transmission although other routes were also reported including drinking dirty water (64%) and eating contaminated food (63%). All caregivers agreed that malaria was a life-threatening disease with the majority of caregivers having received malaria information from health centers (86%) and community health workers (51%). Cumulatively, self-reported mosquito net use was 67%. Respondents reportedly liked the SR prototype product but improvements on color, shape and size were suggested. Overall, 398 mosquitoes were captured from light-trap collections, including 49 anophelines and 349 culicines. Insecticide treated nets use was higher in households from which at least one mosquito was captured. Conclusions: The current study identified misconceptions in malaria transmission among primary caregivers indicating remaining knowledge gaps in educational campaigns. Participant responses also indicated a misalignment between a low perception of IRS efficacy and high stated acceptance of IRS, which should be further examined to better understand uptake and sustainability of other vector control strategies. While ITNs were found to be used in study households, misperceptions between presence of mosquitoes and bite protection practices did exist. This study highlights the importance of knowledge attitudes and practice surveys, with integration of entomological sampling, to better guide malaria vector control product development, strategy acceptance and compliance within endemic communities.

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Section: Sr Productmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Knowledge, attitudes and practices assessment of malaria interventions in rural Zambia

et al. 2020

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“…Our results support SRs as a flexible class of vector control products with positive public health impact not limited to ABV diseases. Transfluthrin- 15 and metofluthrinbased 16,25 mosquito coils have been shown to reduce malaria and the same spatial repellent device used in our Iquitos trial reduced malaria infections in an Indonesia cRCT. 15 Together, these results highlight the potential for SRs to reduce a variety of vector-borne diseases, augment existing public health efforts and be an effective component of vector control intervention strategies.…”

mentioning

confidence: 67%

“…Our intervention was a transfluthrin passive emanator designed and produced by SC Johnson (Racine, WI), replaced at 2-week intervals, as described previously ( Figure S1, SI Section 1.3.2). 16 Spatial repellent and placebo intervention had identical packaging and were deployed in houses by study personnel using a blinded coding scheme. The placement of the intervention followed manufacturer specifications for indoor use conditions.…”

Section: Randomization and Interventionmentioning

confidence: 99%

Efficacy of a Spatial Repellent for Control of Aedes-Borne Virus Transmission: A Cluster Randomized Trial in Iquitos, Peru

Morrison

et al. 2021

Preprint

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Background: Over half the world's population is at risk for viruses transmitted by Aedes mosquitoes, such as, dengue and Zika. The primary vector, Aedes aegypti, thrives in urban environments. Despite decades of effort, cases and the geographic range of Aedes-borne viruses (ABV) continue to expand. To date, there are no rigorously proven vector control interventions that prevent ABV diseases. Spatial repellents, a new option, are designed to decrease human exposure to ABV by releasing active ingredients into the air that disrupt mosquito-human contact. Methods: A parallel, cluster-randomized controlled trial was conducted in Iquitos, Peru to quantify the impact of a transfluthrin-based spatial repellent on ABV infection. From 2,907 households across 26 clusters (13 per arm), 1,578 participants were assessed for seroconversion (primary endpoint) by survival analysis. Incidence of acute disease was calculated among 16,683 participants (secondary endpoint). Bi-monthly adult mosquito collections were conducted to compare Ae. aegypti abundance, blood-fed capture rate and parity status through mixed effect difference-in-difference analyses. Results: The spatial repellent significantly reduced ABV infection by 34.1% (95% CI 6.9%, ∞); p = 0.0236, z=1.98). Aedes aegypti abundance and blood-fed capture rates were significantly reduced by 28.6% (95% CI 24.1%, ∞); z=-9.11) and 12.4% (95% CI 4.2%, ∞); z=-2.43), respectively. Conclusions: Our trial provides the first conclusive evidence of significant protective efficacy by any chemical vector control intervention, in this case a spatial repellent, to reduce the risk of ABV transmission. Results support vector control as a beneficial component to ABV disease prevention. Trial registration number:NCT03553277 (clinicaltrials.gov)

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“…These data emphasize the need for new tools, such as spatial [51] or topical repellents, as well as new research that evaluates novel paradigms directed at residual transmission occurring outside the functional scope of present interventions, accelerating progress towards elimination.…”

Section: Discussionmentioning

confidence: 94%

Anopheline and human drivers of malaria risk in northern coastal, Ecuador: a pilot study

Martin

Hendershot

Portilla

et al. 2020

Malar J

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Background Understanding local anopheline vector species and their bionomic traits, as well as related human factors, can help combat gaps in protection. Methods In San José de Chamanga, Esmeraldas, at the Ecuadorian Pacific coast, anopheline mosquitoes were sampled by both human landing collections (HLCs) and indoor-resting aspirations (IAs) and identified using both morphological and molecular methods. Human behaviour observations (HBOs) (including temporal location and bed net use) were documented during HLCs as well as through community surveys to determine exposure to mosquito bites. A cross-sectional evaluation of Plasmodium falciparum and Plasmodium vivax infections was conducted alongside a malaria questionnaire. Results Among 222 anopheline specimens captured, based on molecular analysis, 218 were Nyssorhynchus albimanus, 3 Anopheles calderoni (n = 3), and one remains unidentified. Anopheline mean human-biting rate (HBR) outdoors was (13.69), and indoors (3.38) (p = 0.006). No anophelines were documented resting on walls during IAs. HBO-adjusted human landing rates suggested that the highest risk of being bitten was outdoors between 18.00 and 20.00 h. Human behaviour-adjusted biting rates suggest that overall, long-lasting insecticidal bed nets (LLINs) only protected against 13.2% of exposure to bites, with 86.8% of exposure during the night spent outside of bed net protection. The malaria survey found 2/398 individuals positive for asymptomatic P. falciparum infections. The questionnaire reported high (73.4%) bed net use, with low knowledge of malaria. Conclusion The exophagic feeding of anopheline vectors in San Jose de Chamanga, when analysed in conjunction with human behaviour, indicates a clear gap in protection even with high LLIN coverage. The lack of indoor-resting anophelines suggests that indoor residual spraying (IRS) may have limited effect. The presence of asymptomatic infections implies the presence of a human reservoir that may maintain transmission.

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Efficacy of a Spatial Repellent for Control of Malaria in Indonesia: A Cluster-Randomized Controlled Trial

Cited by 63 publications

References 49 publications

Knowledge, attitudes and practices assessment of malaria interventions in rural Zambia

Knowledge, attitudes and practices assessment of malaria interventions in rural Zambia

Efficacy of a Spatial Repellent for Control of Aedes-Borne Virus Transmission: A Cluster Randomized Trial in Iquitos, Peru

Anopheline and human drivers of malaria risk in northern coastal, Ecuador: a pilot study

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