Effect of long-lasting insecticidal nets with and without piperonyl butoxide on malaria indicators in Uganda (LLINEUP): a pragmatic, cluster-randomised trial embedded in a national LLIN distribution campaign

Staedke, Sarah G.; Gonahasa, Samuel; Dorsey, Grant; Kamya, Moses R.; Maiteki‐Sebuguzi, Catherine; Lynd, Amy; Katureebe, Agaba; Kyohere, Mary; Mutungi, Peter; Kigozi, Simon P.; Opigo, Jimmy; Hemingway, Janet; Donnelly, Martin

doi:10.1016/s0140-6736(20)30214-2

Cited by 149 publications

(174 citation statements)

References 29 publications

Supporting

Mentioning

164

Contrasting

Order By: Relevance

“…Dual-active ITNs (pyrethroid plus piperonyl butoxide (PBO) or pyrethroid plus chlofenapyr) are now being deployed in the study area. PBO-pyrethroid ITNs have been shown to be more effective in reducing malaria than pyrethroid-only ITNs in areas of pyrethroid-resistant vectors [50,51], and monitoring of the effectiveness of these dual active ITNs is ongoing in Burkina Faso. Indoor residual spraying (IRS) should also be considered as it has been shown to be effective in reducing malaria in other high-burden countries.…”

Section: Discussionmentioning

confidence: 99%

A cohort study to identify risk factors for Plasmodium falciparum infection in Burkinabe children: implications for other high burden high impact countries

Yaro

Ouédraogo

Ouedraogo

et al. 2020

Preprint

View full text Add to dashboard Cite

Background Progress in controlling malaria has stalled in recent years. Today the malaria burden is increasingly concentrated in a few countries, including Burkina Faso, where malaria is not declining. A cohort study was conducted to identify risk factors for malaria infection in children in southwest Burkina Faso, an area with high insecticide-treated net (ITN) coverage and insecticide-resistant vectors.Methods Incidence of Plasmodium falciparum infection was measured in 252 children aged 5 to 15 years, using active and passive detection, during the 2017 transmission season, following clearance of infection. Demographic, socio-economic, environmental, and entomological risk factors, including use of ITNs and insecticide resistance were monitored. Results During the six-month follow-up period, the overall incidence of P. falciparum infection was 2.78 episodes per child (95% CI= 2.66-2.91) by microscopy, and 3.11 (95% CI= 2.95-3.28) by polymerase chain reaction (PCR). The entomological inoculation rate (EIR) was 80.4 infective bites per child over the six-month malaria transmission season. At baseline, 80.6% of children were reported as sleeping under an ITN the previous night, although at the last survey, 23.3% of nets were in poor condition and considered no longer protective. No association was found between the rate of P. falciparum infection and either EIR (incidence rate ratio (IRR): 1.00, 95% CI: 1.00-1.00, p=0.08) or mortality in WHO tube tests when vectors were exposed to 0.05% deltamethrin (IRR: 1.05, 95% CI: 0.73-1.50, p=0.79). Travel history (IRR: 1.52, 95% CI: 1.45-1.59, p<0.001) and higher socio-economic status were associated with an increased risk of P. falciparum infection (IRR: 1.05, 95% CI: 1.00-1.11, p=0.04).Conclusions Incidence of P. falciparum infection remains overwhelmingly high in the study area. The study findings suggest that because of the exceptionally high levels of malaria transmission in the study area, malaria elimination cannot be achieved solely by mass deployment of ITNs and additional control measures are needed.

show abstract

Section: Discussionmentioning

confidence: 99%

A cohort study to identify risk factors for Plasmodium falciparum infection in Burkinabe children: implications for other high burden high impact countries

Yaro

Ouédraogo

Ouedraogo

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…More recently, another large-scale trial has been completed in 48 Ugandan districts with high pyrethroid resistance comparing PBO nets (i.e. Olyset Plus and PermaNet 3.0) with non-PBO nets (Olyset and PermaNet 2.0) [ 196 ]. The investigators measured malaria parasite prevalence among 2–10 year-olds, and demonstrated that any benefits accruable from the PBO nets over standard ITNs were marginal at 6 months (11% in PBO group versus 15% in non-PBO group), and null after 12 and 18 months.…”

Section: Could Itns With Multiple Active Ingredients Restore Insecticmentioning

confidence: 99%

“…The investigators measured malaria parasite prevalence among 2–10 year-olds, and demonstrated that any benefits accruable from the PBO nets over standard ITNs were marginal at 6 months (11% in PBO group versus 15% in non-PBO group), and null after 12 and 18 months. Surprisingly, the authors concluded, contrary to their own findings that the PBO nets were more effective, and even went further to suggest that their evidence should be adopted by the WHO to provide the “final” recommendation for PBO-Nets [ 196 ].…”

Section: Could Itns With Multiple Active Ingredients Restore Insecticmentioning

confidence: 99%

The fabric of life: what if mosquito nets were durable and widely available but insecticide-free?

Okumu

2020

Malar J

View full text Add to dashboard Cite

Background: Bed nets are the commonest malaria prevention tool and arguably the most cost-effective. Their efficacy is because they prevent mosquito bites (a function of physical durability and integrity), and kill mosquitoes (a function of chemical content and mosquito susceptibility). This essay follows the story of bed nets, insecticides and malaria control, and asks whether the nets must always have insecticides. Methods: Key attributes of untreated or pyrethroid-treated nets are examined alongside observations of their entomological and epidemiological impacts. Arguments for and against adding insecticides to nets are analysed in contexts of pyrethroid resistance, personal-versus-communal protection, outdoor-biting, need for local production and global health policies. Findings: Widespread resistance in African malaria vectors has greatly weakened the historical mass mosquitocidal effects of insecticide-treated nets (ITNs), which previously contributed communal benefits to users and non-users. Yet ITNs still achieve substantial epidemiological impact, suggesting that physical integrity, consistent use and population-level coverage are increasingly more important than mosquitocidal properties. Pyrethroid-treatment remains desirable where vectors are sufficiently susceptible, but is no longer universally necessary and should be reexamined alongside other attributes, e.g. durability, coverage, acceptability and access. New ITNs with multiple actives or synergists could provide temporary relief in some settings, but their performance, higher costs, and drawn-out innovation timelines do not justify singular emphasis on insecticides. Similarly, sub-lethal insecticides may remain marginallyimpactful by reducing survival of older mosquitoes and disrupting parasite development inside the mosquitoes, but such effects vanish under strong resistance. Conclusions: The public health value of nets is increasingly driven by bite prevention, and decreasingly by lethality to mosquitoes. For context-appropriate solutions, it is necessary to acknowledge and evaluate the potential and costeffectiveness of durable untreated nets across different settings. Though ~ 90% of malaria burden occurs in Africa, most World Health Organization-prequalified nets are manufactured outside Africa, since many local manufacturers lack capacity to produce the recommended insecticidal nets at competitive scale and pricing. By relaxing conditions for insecticides on nets, it is conceivable that non-insecticidal but durable, and possibly biodegradable nets, could be readily manufactured locally. This essay aims not to discredit ITNs, but to illustrate how singular focus on insecticides can hinder innovation and sustainability.

show abstract

“…In a cluster randomized trial conducted in the same area as the present study, full coverage with PBO-Py ITNs (Olyset Plus) provided community protection against malaria up to 2 years of use (12). A further study, this one in Uganda, showed higher e cacy of PBO-Py ITNs compared to standard LLIN over the 18 months duration of the trial (13).…”

Section: Introductionmentioning

confidence: 54%

Personal Protection with PBO-Pyrethroid Synergist Treated Nets After Two Years of Household Use Against Pyrethroid-Resistant Anopheles in Tanzania

Martin

Mosha

Lukole

et al. 2020

Preprint

View full text Add to dashboard Cite

Background: The spread of pyrethroid resistance in malaria vectors threatens the effectiveness of standard long-lasting insecticidal nets (LLIN). Synergist nets combine pyrethroid (Py) and piperonyl-butoxide (PBO) to enhance potency against resistance mediated by mono-oxygenase mechanisms. Our project assessed personal protection of WHO first-in-class PBO-Py treated nets (Olyset Plus) versus standard LLIN (Olyset net) against pyrethroid resistant Anopheles gambiae and An. funestus in North West Tanzania after 20 months of household use.Methods: From household survey, 39 standard Olyset net and 39 Olyset Plus houses were selected, physical integrity and hole index (HI) of nets assessed, resting mosquitoes collected from inside nets and from room walls, indoor abundance estimated using CDC light traps and species identified using PCR. Residual bio-efficacy of PBO and standard LLINs was assessed using 30 min cylinder bioassays.Results: Of 2397 Anopheles collected, 8.9% (n=213) were resting inside standard Olyset nets while none were found inside Olyset Plus PBO-Py nets of any HI category. Resting density of blood fed mosquitoes was higher on walls of sleeping rooms with Olyset net compared to Olyset Plus (0.62 vs 0.10, density ratio: 0.03, 95% CI: 0.01-0.13, p<0.001). Mosquitoes were found inside Olyset nets of all WHO HI categories but more were collected inside the more damaged (HI≥ 643) nets than in less damaged (HI 0-64) nets (DR: 6.4, 95% CI: 1.1-36.0, p=0.037). In residual bioassay, mortality of An. gambiae s.l was higher with Olyset Plus than with Olyset net for new nets (76.8% vs 27.5%) and 20 months’ nets (56.8% vs 12.8%); similar trends were observed with An. funestus. Conclusion: The PBO-Py treated net provided improved protection after 20 months of household use, as demonstrated by the higher bioassay mortality and absence of pyrethroid resistant An. gambiae s.s. and An. funestus collected from inside Olyset Plus, irrespective of hole index category, as compared to Olyset nets.

show abstract

Effect of long-lasting insecticidal nets with and without piperonyl butoxide on malaria indicators in Uganda (LLINEUP): a pragmatic, cluster-randomised trial embedded in a national LLIN distribution campaign

Cited by 149 publications

References 29 publications

A cohort study to identify risk factors for Plasmodium falciparum infection in Burkinabe children: implications for other high burden high impact countries

A cohort study to identify risk factors for Plasmodium falciparum infection in Burkinabe children: implications for other high burden high impact countries

The fabric of life: what if mosquito nets were durable and widely available but insecticide-free?

Personal Protection with PBO-Pyrethroid Synergist Treated Nets After Two Years of Household Use Against Pyrethroid-Resistant Anopheles in Tanzania

Contact Info

Product

Resources

About