Long-Lasting Insecticidal Nets retain bio-efficacy after five years of storage: implications for malaria control programmes

Abstract Background: Long Lasting Insecticidal Nets (LLINs) are the most sustainable and effective malaria control tool currently available. Global targets are for 80% of the population living in malaria endemic areas to have access to (own) and use a LLIN. However, current access to LLINs in endemic areas is 56% due to system inefficiencies and budget limitations. Thus, cost-effective approaches to maximize access of effective LLINs in endemic areas are required. This study evaluated whether LLINs that had been stored for five years under manufacturer’s recommended conditions may be optimally effective against Anopheles mosquitoes, to inform malaria control programs and governments on the periods over which LLINs may be stored between distributions, in an effort to maximise use of available LLINs. Methods: Standard World Health Organization (WHO) bioassays (cone and tunnel test) were used to evaluate the bio-efficacy and wash resistance of Olyset® and DawaPlus® 2.0 (rebranded Tsara® Soft) LLINs after five years of storage at 25°C - 33.4°C and 40% - 100% relative humidity. In addition a small scale, Ifakara Ambient Chamber tests (I-ACT) were conducted to compare the bio-efficacy of one long stored LLINs to one new LLIN of the same brand, washed or unwashed. LLINs were evaluated using laboratory reared fully susceptible Anopheles gambiae s.s. (Ifakara) and pyrethroid resistant Anopheles arabiensis (Kingani). Results: After five years of storage, both unwashed and washed, Olyset® and DawaPlus® 2.0 LLINs passed WHO bio-efficacy criteria on knockdown (KD60) ≥95%, 24-hour mortality ≥80% and ≥90% blood-feeding inhibition in WHO assays against susceptible An. gambiae s.s. DawaPlus® 2.0 LLINs also passed combined WHO bioassay criteria against resistant An. arabiensis. Confirmatory I-ACT tests using whole nets demonstrated that long stored LLINs showed higher efficacy than new LLINs on both feeding inhibition and mortality endpoints against resistant strains. Conclusions: Even after long-term storage of around 5 years, Olyset® and DawaPlus® 2.0 LLINs remain efficacious against susceptible Anopheles mosquitoes at optimal storage range of 25°C - 33.4°C for temperature and 40% - 100% relative humidity measured by standard WHO methods.

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Long-Lasting Insecticidal Nets retain bio-efficacy after five years of storage: implications for malaria control programmes

10.21203/rs.2.17717/v2 ◽

2020 ◽

Author(s):

Jeremiah John Musa ◽

Sarah Moore ◽

Jason Moore ◽

Emmanuel Mbuba ◽

Edgar Mbeyela ◽

...

Keyword(s):

Relative Humidity ◽

Malaria Control ◽

World Health ◽

Small Scale ◽

Anopheles Gambiae S.S ◽

Feeding Inhibition ◽

Anopheles Mosquitoes ◽

Control Programmes ◽

Endemic Areas ◽

Long Lasting Insecticidal Nets

Abstract Background: Long Lasting Insecticidal Nets (LLINs) are the most sustainable and effective malaria control tool currently available. Global targets are for 80% of the population living in malaria endemic areas to have access to (own) and use a LLIN. However, current access to LLINs in endemic areas is 56% due to system inefficiencies and budget limitations. Thus, cost-effective approaches to maximize access to effective LLINs in endemic areas are required. This study evaluated whether LLINs that had been stored for five years under manufacturer’s recommended conditions may be optimally effective against Anopheles mosquitoes, to inform malaria control programmes and governments on the periods over which LLINs may be stored between distributions, in an effort to maximise use of available LLINs. Methods: Standard World Health Organization (WHO) bioassays (cone and tunnel test) were used to evaluate the bio-efficacy and wash resistance of Olyset ® and DawaPlus ® 2.0 (rebranded Tsara ® Soft) LLINs after five years of storage at 25°C - 33.4°C and 40% - 100% relative humidity. In addition, a small scale Ifakara Ambient Chamber test (I-ACT) was conducted to compare the bio-efficacy of one long stored LLINs to one new LLIN of the same brand, washed or unwashed. LLINs were evaluated using laboratory reared fully susceptible Anopheles gambiae s.s (Ifakara strain) and pyrethroid resistant Anopheles arabiensis (Kingani strain). Results: After five years of storage, both unwashed and washed, Olyset ® and DawaPlus ® 2.0 (Tsara ® Soft) LLINs passed WHO bio-efficacy criteria on knockdown (KD60) ≥95%, 24-hour mortality ≥80% and ≥90% blood-feeding inhibition in WHO assays against susceptible An. gambiae s.s. DawaPlus ® 2.0 LLINs also passed combined WHO bioassay criteria against resistant An. arabiensis. Confirmatory I-ACT tests using whole nets demonstrated that long-stored LLINs showed higher efficacy than new LLINs on both feeding inhibition and mortality endpoints against resistant strains. Conclusions: Even after long-term storage of around 5 years, both Olyset ® and DawaPlus ® 2.0 LLINs remain efficacious against susceptible Anopheles mosquitoes at optimal storage range of 25°C - 33.4°C for temperature and 40% - 100% relative humidity measured by standard WHO methods. DawaPlus ® 2.0 (Tsara ® Soft) remained efficacious against resistant strain.

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Long-lasting insecticidal nets retain bio-efficacy after five years of storage: implications for malaria control programmes

10.21203/rs.2.17717/v3 ◽

2020 ◽

Author(s):

Jeremiah John Musa ◽

Sarah Moore ◽

Jason Moore ◽

Emmanuel Mbuba ◽

Edgar Mbeyela ◽

...

Keyword(s):

Relative Humidity ◽

Malaria Control ◽

Blood Feeding ◽

Sensu Stricto ◽

World Health ◽

Small Scale ◽

Feeding Inhibition ◽

Control Programmes ◽

Endemic Areas ◽

Long Lasting Insecticidal Nets

Abstract Background: Long-lasting insecticidal nets (LLINs) are the most sustainable and effective malaria control tool currently available. Global targets are for 80% of the population living in malaria endemic areas to have access to (own) and use a LLIN. However, current access to LLINs in endemic areas is 56% due to system inefficiencies and budget limitations. Thus, cost-effective approaches to maximize access to effective LLINs in endemic areas are required. This study evaluated whether LLINs that had been stored for five years under manufacturer’s recommended conditions may be optimally effective against Anopheles mosquitoes, to inform malaria control programmes and governments on the periods over which LLINs may be stored between distributions, in an effort to maximize use of available LLINs. Methods: Standard World Health Organization (WHO) bioassays (cone and tunnel test) were used to evaluate the bio-efficacy and wash resistance of Olyset® and DawaPlus® 2.0 (rebranded Tsara® Soft) LLINs after five years of storage at 25°C to 33.4°C and 40% to 100% relative humidity. In addition, a small scale Ifakara Ambient Chamber test (I-ACT) was conducted to compare the bio-efficacy of one long stored LLINs to one new LLIN of the same brand, washed or unwashed. LLINs were evaluated using laboratory reared fully susceptible Anopheles gambiae sensu stricto (s.s.) (Ifakara strain) and pyrethroid resistant Anopheles arabiensis (Kingani strain). Results: After five years of storage, both unwashed and washed, Olyset® and DawaPlus® 2.0 (Tsara® Soft) LLINs passed WHO bio-efficacy criteria on knockdown (KD60) ≥95%, 24-hour mortality ≥80% and ≥90% blood-feeding inhibition in WHO assays against susceptible An. gambiae s.s. DawaPlus® 2.0 LLINs also passed combined WHO bioassay criteria against resistant An. arabiensis. Confirmatory I-ACT tests using whole nets demonstrated that long-stored LLINs showed higher efficacy than new LLINs on both feeding inhibition and mortality endpoints against resistant strains.Conclusions: Even after long-term storage of around 5 years, both Olyset® and DawaPlus® 2.0 LLINs remain efficacious against susceptible Anopheles mosquitoes at optimal storage range of 25°C to 33.4°C for temperature and 40% to 100% relative humidity measured by standard WHO methods. DawaPlus® 2.0 (Tsara® Soft) remained efficacious against resistant strain.

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The First GLP Compliant Study in Africa for the Evaluation of LLIN’s; Efficacy of SafeNet® and SafeNet NF®

10.21203/rs.3.rs-1006810/v1 ◽

2021 ◽

Author(s):

Salum Azizi ◽

Janneke Snetselaar ◽

Robert Kaaya ◽

Johnson Matowo ◽

Hudson Onen ◽

...

Keyword(s):

Universal Coverage ◽

Blood Feeding ◽

World Health ◽

Manufacturing Cost ◽

Feeding Inhibition ◽

Evaluation Scheme ◽

Residual Efficacy ◽

Good Laboratory ◽

Health Organization ◽

Long Lasting Insecticidal Nets

Abstract Background: To attain and sustain the universal Long-Lasting Insecticidal Nets (LLINs) coverage, cheap nets that provides equivalent or better protection than the standard LLINs, are required. While it is essential to follow the World Health Organization (WHO) guidelines for the evaluation of LLINs, adherence to the Good Laboratory Practice (GLP) is necessary to generate reliable and reproducible data that will facilitate efficient LLINs to be speedy registered. Adherence to GLP obviate the need to duplicate the assessment and ensures substandard LLINs are not reaching the market. This study aimed to evaluate efficacy of SafeNet NF® and SafeNet® LLIN in accordance to the WHO Pest Evaluation Scheme (WHOPES) and the GLP guidelines. Both candidate LLINs were manufactured with less fabrics to cut down manufacturing costs, motivated by the need for cheaper LLINs to achieve universal coverage. Materials & Methods: SafeNet NF® and SafeNet® LLIN, were assessed in experimental huts against wild, pyrethroid-resistant Anopheles arabiensis mosquitoes. Efficacy in terms of mosquito blood-feeding inhibition and mortality, was compared with Interceptor® LLIN and an untreated net. All nets were washed and artificially holed to simulate a used torn net. The GLP guidelines were followed throughout this study.Results: The mortality of mosquitoes exposed to SafeNet NF® and SafeNet® LLIN were equivalent to that of the reference net. Blood-feeding inhibition was only evident in Interceptor® LLIN. Adherence to GLP was observed throughout the study.Conclusions: Step-wise procedures to conduct LLIN evaluation in compliance to both WHOPES and GLP guidelines are elaborated in this study. SafeNet NF® and SafeNet® LLIN offers equivalent protection as Interceptor® LLIN and can facilitate universal LLIN coverage due to its low manufacturing cost. However, further research is needed to understand durability, acceptability and residual efficacy of these nets in field environments.

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Bio-efficacy and wash resistance of MAGNet long-lasting insecticidal net against wild populations of Anopheles funestus in experimental huts in Muheza, Tanzania

Malaria Journal ◽

10.1186/s12936-019-2973-x ◽

2019 ◽

Vol 18 (1) ◽

Author(s):

Eliningaya J. Kweka ◽

Patrick K. Tungu ◽

Aneth M. Mahande ◽

Humphrey D. Mazigo ◽

Subira Sayumwe ◽

...

Keyword(s):

Anopheles Funestus ◽

Blood Feeding ◽

Personal Protection ◽

Feeding Rates ◽

Feeding Inhibition ◽

Experimental Huts ◽

Host Seeking ◽

Mosquito Mortality ◽

Resistant Population ◽

Long Lasting Insecticidal Nets

Abstract Background The decline in malaria cases and vectors is major milestone in fighting against malaria. The efficacy of MAGNet long-lasting insecticidal nets (MAGNet LLIN), an alpha-cypermethrin incorporated long-lasting net, with the target dose ± 25% of 5.8 g active ingredient (AI)/kg (4.35–7.25 g AI/kg) was evaluated in six veranda-trap experimental huts in Muheza, Tanzania against freely flying wild population of Anopheles funestus. Methods MAGNet LLINs were tested against wild, free-flying, host-seeking An. funestus mosquitoes over a period of 6 weeks (total of 36 nights in the huts). MAGNet LLIN efficacy was determined in terms of mosquito mortality, blood-feeding inhibition, deterrence, induced exiting, personal protection, and insecticidal killing over 20 washes according to WHO standardized procedures. Efficacy was compared with reference to a WHOPES recommended approved LLINs (DuraNet) and to a net conventionally treated (CTN) treated with alpha-cypermethrin at WHO-recommended dose and washed to just before cut-off point. The efficacy of MAGNet was evaluated in experimental huts against wild, free-flying, pyrethroid-resistant An. funestus. The WHO-susceptibility method was used to detect resistance in wild Anopheles exposed to 0.75% permethrin. Mosquito mortality, blood-feeding inhibition and personal protection were compared between untreated nets and standard LLINs. Blood-feeding rates were recorded and compared between the 20 times washed; blood-feeding rates between 20 times washed MAGNet LLIN and 20 times washed WHOPES-approved piperonyl butoxide (PBO)/pyrethroid were not statistically different (p > 0.05). Results The results have evidently shown that MAGNet LLIN provides similar blood-feeding inhibition, exophily, mortality, and deterrence to the standard approved LLIN, thus meeting the WHOPES criteria for blood feeding. The significantly high feeding inhibition and personal protection over pyrethroid-resistant An. funestus recorded by both unwashed and 20 times washed MAGNet compared to the unwashed DuraNet, the WHOPES-approved standard pyrethroid-only LLIN provides proof of MAGNet meeting Phase II WHOPES criteria for a LLIN. Conclusion Based on this study, MAGNet has been shown to have a promising impact on protection when 20 times washed against a highly resistant population of An. funestus.

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Comparative functional survival and equivalent annual cost of three long lasting insecticidal net (LLIN) products in Tanzania

10.1101/19002212 ◽

2019 ◽

Cited By ~ 4

Author(s):

Lena M Lorenz ◽

John Bradley ◽

Joshua Yukich ◽

Dennis Joram Massue ◽

Zawadi Mageni Mboma ◽

...

Keyword(s):

Malaria Control ◽

Primary Outcome ◽

Protective Efficacy ◽

World Health ◽

Prospective Evaluation ◽

Chemical Content ◽

Secondary Outcomes ◽

Health Organization ◽

Double Blinded ◽

Long Lasting Insecticidal Nets

AbstractAlmost 1.2 billion long-lasting insecticidal nets (LLINs) have been procured for malaria control. Institutional buyers often assume that World Health Organization (WHO) prequalified LLINs are functionally identical with a three-year lifespan. We measured the lifespans of three LLIN products, and calculated their cost-per-year of functional life, through a randomised double-blinded prospective evaluation among 3,420 study households in Tanzania using WHO-recommended methods. Primary outcome was LLIN functional survival (LLINs present in serviceable condition). Secondary outcomes were 1) bioefficacy and chemical content (residual insecticidal activity) and 2) protective efficacy for volunteers sleeping under LLINs (bite reduction and mosquitoes killed). LLIN median functional survival was significantly different: 2·0 years for Olyset, 2·5 years for PermaNet and 2·6 years for NetProtect. Functional survival was affected by accumulation of holes resulting in users discarding nets. Protective efficacy also significantly differed between products as they aged. The longer-lived nets were 20% cheaper than the shorter-lived product.

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Increased prevalence of insecticide resistance in Anopheles coluzzii populations in the city of Yaoundé, Cameroon and influence on pyrethroid-only treated bed net efficacy

Parasite ◽

10.1051/parasite/2021003 ◽

2021 ◽

Vol 28 ◽

pp. 8

Author(s):

Roland Bamou ◽

Edmond Kopya ◽

Leslie Diane Nkahe ◽

Benjamin D. Menze ◽

Parfait Awono-Ambene ◽

...

Keyword(s):

Insecticide Resistance ◽

Malaria Vector ◽

Blood Feeding ◽

World Health ◽

Bed Nets ◽

Anopheles Coluzzii ◽

Feeding Inhibition ◽

Cone Bioassay ◽

Health Organization ◽

The City

In Cameroon, pyrethroid-only long-lasting insecticidal nets (LLINs) are still largely used for malaria control. The present study assessed the efficacy of such LLINs against a multiple-resistant population of the major malaria vector, Anopheles coluzzii, in the city of Yaoundé via a cone bioassay and release-recapture experimental hut trial. Susceptibility of field mosquitoes in Yaoundé to pyrethroids, DDT, carbamates and organophosphate insecticides was investigated using World Health Organization (WHO) bioassay tube tests. Mechanisms of insecticide resistance were characterised molecularly. Efficacy of unwashed PermaNet® 2.0 was evaluated against untreated control nets using a resistant colonised strain of An. coluzzii. Mortality, exophily and blood feeding inhibition were estimated. Field collected An. coluzzii displayed high resistance with mortality rates of 3.5% for propoxur (0.1%), 4.16% for DDT (4%), 26.9% for permethrin (0.75%), 50.8% for deltamethrin (0.05%), and 80% for bendiocarb (0.1%). High frequency of the 1014F west-Africa kdr allele was recorded in addition to the overexpression of several detoxification genes, such as Cyp6P3, Cyp6M2, Cyp9K1, Cyp6P4 Cyp6Z1 and GSTe2. A low mortality rate (23.2%) and high blood feeding inhibition rate (65%) were observed when resistant An. coluzzii were exposed to unwashed PermaNet® 2.0 net compared to control untreated net (p < 0.001). Furthermore, low personal protection (52.4%) was observed with the resistant strain, indicating reduction of efficacy. The study highlights the loss of efficacy of pyrethroid-only nets against mosquitoes exhibiting high insecticide resistance and suggests a switch to new generation bed nets to improve control of malaria vector populations in Yaoundé.

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Evaluation of Long-Lasting Insecticidal Nets (DuraNet®) Under laboratory and Semi-Field Conditions Using Experimental Huts Against Anopheles Mosquitoes in Jimma Zone, Southwestern Ethiopia

Environmental Health Insights ◽

10.1177/1178630220974730 ◽

2021 ◽

Vol 15 ◽

pp. 117863022097473

Author(s):

Brhane Gebremariam ◽

Wondwosen Birke ◽

Wuhib Zeine ◽

Argaw Ambelu ◽

Delenasaw Yewhalaw

Keyword(s):

Insecticide Resistance ◽

World Health ◽

Anopheles Mosquitoes ◽

Southwestern Ethiopia ◽

Vector Population ◽

Experimental Huts ◽

Cone Bioassay ◽

The Mean ◽

Health Organization ◽

Long Lasting Insecticidal Nets

Background: Long-Lasting Insecticidal Nets (LLINs) efficacy could be compromised due to a lot of influences together with user compliance and vector population insecticide resistance status. Thus, this study was to assess the biological efficacy of DuraNet® with the help of the World Health Organization cone bioassay and field experimental hut. Methods: A laboratory and a semi-field conditions experimental huts against Anopheles Mosquitoes were conducted in southwestern Ethiopia from September 2015 to January 2016. The bio efficacy of DuraNet® was evaluated using the WHO cone bioassay test and then its field efficacy was evaluated using experimental huts against the malaria vector population. Results: World Health Organization cone bioassay tests against pyrethroid-resistant An. arabiensis led to mean percent mortality and knockdown of 78% and 93%, respectively. Washing of DuraNet® successively reduced its efficacy from 93% knockdown (0 wash) to 45% knockdown (20 washes). Similarly, mean mortality decreased from 84% (0 wash) to 47% (20 washes). A total of 1575 female mosquitoes were collected over 40 nights out of which 1373(87.8%) were An. gambiae s.l., 116 (7.4%) were Anopheles coustani and 107 (6.8%) were An. pharoensis. The mean blood-feeding rate was significantly lower ( P < .001) in hut containing unwashed DuraNet® when compared to hut containing untreated DuraNet®. The mean mortality rate was significantly higher ( P < .001) in hut containing DuraNet® when compared to hut containing untreated DuraNet®. Unwashed DuraNet® showed the highest personal protection 88.7% and 100% against An. Arabiensis and An. pharoensis, respectively. Conclusion: Both DuraNet® and PermaNet 2.0 moderate efficacy against a pyrethroid-resistant population of An. arabiensis from Ethiopia. The bio efficacy of DuraNet® was found below the WHO recommendation. Therefore, the real impact of the observed insecticide resistance against DuraNet® to be further studied under phase-III trials, the need for new alternative vector control tools remains critical.

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Efficacy of Long-lasting Insecticidal Nets With Declining Physical and Chemical Integrity on Aedes aegypti (Diptera: Culicidae)

Journal of Medical Entomology ◽

10.1093/jme/tjz176 ◽

2019 ◽

Author(s):

Josué Herrera-Bojórquez ◽

Emilio Trujillo-Peña ◽

José Vadillo-Sánchez ◽

Martin Riestra-Morales ◽

Azael Che-Mendoza ◽

...

Keyword(s):

Aedes Aegypti ◽

Residual Activity ◽

Blood Feeding ◽

Chemical Effect ◽

Feeding Inhibition ◽

Mosquito Mortality ◽

Field Deployment ◽

Deployment Time ◽

Long Lasting Insecticidal Nets ◽

Over Time

Abstract Fitting long-lasting insecticidal nets (LLIN) as screens on doors/windows has a significant impact on indoor-adult Aedes aegypti (L.), with entomological reductions measured in a previous study being significant for up to 2 yr post-installation, even in the presence of pyrethroid-resistant Aedes populations. To better understand the mode of LLIN protection, bioassays were performed to evaluate the effects of field deployment (0, 6, and 12 mo) and damage type (none, central, lateral, and multiple) on LLIN efficacy. Contact bioassays confirmed that LLIN residual activity (median knockdown time, in minutes, or MKDT) decreased significantly over time: 6.95 (95% confidence interval [CI]: 5.32–8.58) to 9.24 (95% CI: 8.69–9.79) MKDT at 0- and 12-mo age, respectively, using a pyrethroid-susceptible Aedes strain. Tunnel tests (exposing human forearm for 40 min as attractant) showed that deployment time affected negatively Aedes passage inhibition from 54.9% (95% CI: 43.5–66.2) at 0 mo to 35.7% (95% CI: 16.3–55.1) at 12 mo and blood-feeding inhibition from 65.2% (95% CI: 54.2–76.2) to 48.9% (95% CI: 26.4–71.3), respectively; both the passage/blood-feeding inhibition increased by a factor of 1.8–2.9 on LLINs with multiple and central damages compared with nets with lateral damage. Mosquito mortality was 74.6% (95% CI: 65.3–83.9) at 0 mo, 72.3% (95% CI: 64.1–80.5) at 6 mo, and 59% (95% CI: 46.7–71.3) at 12 mo. Despite the LLIN physical integrity could be compromised over time, we demonstrate that the remaining chemical effect after field conditions would still contribute to killing/repelling mosquitoes.

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Efficacy of interceptor® G2, a long-lasting insecticide mixture net treated with chlorfenapyr and alpha-cypermethrin against Anopheles funestus: experimental hut trials in north-eastern Tanzania

Malaria Journal ◽

10.1186/s12936-021-03716-z ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Patrick K. Tungu ◽

Elisante Michael ◽

Wema Sudi ◽

William W. Kisinza ◽

Mark Rowland

Keyword(s):

Pyrethroid Resistance ◽

Meta Analysis ◽

Anopheles Funestus ◽

Blood Feeding ◽

Significant Loss ◽

World Health ◽

Cross Resistance ◽

Personal Protection ◽

Experimental Hut ◽

Field Evidence

Abstract Background The effectiveness of long-lasting insecticidal nets (LLIN), the primary method for preventing malaria in Africa, is compromised by evolution and spread of pyrethroid resistance. Further gains require new insecticides with novel modes of action. Chlorfenapyr is a pyrrole insecticide that disrupts mitochrondrial function and confers no cross-resistance to neurotoxic insecticides. Interceptor® G2 LN (IG2) is an insecticide-mixture LLIN, which combines wash-resistant formulations of chlorfenapyr and the pyrethroid alpha-cypermethrin. The objective was to determine IG2 efficacy under controlled household-like conditions for personal protection and control of wild, pyrethroid-resistant Anopheles funestus mosquitoes. Methods Experimental hut trials tested IG2 efficacy against two positive controls—a chlorfenapyr-treated net and a standard alpha-cypermethrin LLIN, Interceptor LN (IG1)—consistent with World Health Organization (WHO) evaluation guidelines. Mosquito mortality, blood-feeding inhibition, personal protection, repellency and insecticide-induced exiting were recorded after zero and 20 washing cycles. The trial was repeated and analysed using multivariate and meta-analysis. Results In the two trials held in NE Tanzania, An. funestus mortality was 2.27 (risk ratio 95% CI 1.13–4.56) times greater with unwashed Interceptor G2 than with unwashed Interceptor LN (p = 0.012). There was no significant loss in mortality with IG2 between 0 and 20 washes (1.04, 95% CI 0.83–1.30, p = 0.73). Comparison with chlorfenapyr treated net indicated that most mortality was induced by the chlorfenapyr component of IG2 (0.96, CI 0.74–1.23), while comparison with Interceptor LN indicated blood-feeding was inhibited by the pyrethroid component of IG2 (IG2: 0.70, CI 0.44–1.11 vs IG1: 0.61, CI 0.39–0.97). Both insecticide components contributed to exiting from the huts but the contributions were heterogeneous between trials (heterogeneity Q = 36, P = 0.02). WHO susceptibility tests with pyrethroid papers recorded 44% survival in An. funestus. Conclusions The high mortality recorded by IG2 against pyrethroid-resistant An. funestus provides first field evidence of high efficacy against this primary, anthropophilic, malaria vector.

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