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Mechan, Frank, Katureebe, Agaba, Tuhaise, Violet, Mugote, Martin, Oruni, Ambrose, Onyige, Ismail, Bumali, Kawesa, Thornton, Jonathan, Maxwell, Kilama, Kyohere, Mary, Kamya, Moses R., Mutungi, Peter, Kigozi, Simon P., Yeka, Adoke, Opigo, Jimmy, Maiteki-Sebuguzi, Catherine, Gonahasa, Samuel, Hemingway, Janet 
ORCID: https://orcid.org/0000-0002-3200-7173, Dorsey, Grant, Reimer, Lisa ORCID: https://orcid.org/0000-0002-9711-4981, Staedke, Sarah G., Donnelly, Martin ORCID: https://orcid.org/0000-0001-5218-1497 and Lynd, Amy ORCID: https://orcid.org/0000-0001-6054-0525
(2022)
'LLIN evaluation in Uganda project (LLINEUP): The fabric integrity, chemical content and bioefficacy of long-lasting insecticidal nets treated with and without piperonyl butoxide across two years of operational use in Uganda'. Current Research in Parasitology and Vector-Borne Diseases, Vol 2, e100092.
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LLIN evaluation in Uganda project LLINEUP The fabric integrity chemical content and bioefficacy of long-lasting insecticidal nets treated with and without piperonyl butoxide across two years of operational use in Uganda.pdf - Published Version Available under License Creative Commons Attribution. Download (1MB) | Preview |
Abstract
Long-lasting insecticidal nets (LLINs) supplemented with the synergist piperonyl butoxide have been developed in response to growing pyrethroid resistance; however, their durability in the field remains poorly described. A pragmatic cluster-randomised trial was embedded into Ugandaʼs 2017–2018 LLIN distribution to compare the durability of LLINs with and without PBO. A total of 104 clusters (health sub-districts) were included with each receiving one of four LLIN products, two with pyrethroid þ PBO (Olyset Plus and PermaNet 3.0) and two pyrethroid-only (Olyset Net and PermaNet 2.0). Nets were sampled at baseline, 12 and 25 months postdistribution to assess physical condition, chemical content, and bioefficacy. Physical condition was quantified using proportionate Hole Index and chemical content measured using high-performance liquid chromatography. Bioefficacy was assessed with three-minute World Health Organisation (WHO) Cone and Wireball assays using pyrethroid-resistant Anopheles gambiae, with 1-h knockdown and 24-h mortality recorded. There was no difference in physical durability between LLIN products assessed (P ¼ 0.644). The pyrethroid content of all products remained relatively stable across time-points but PBO content declined by 55% (P < 0.001) and 58% (P < 0.001) for Olyset Plus and PermaNet 3.0 respectively. Both PBO LLINs were highly effective against pyrethroid-resistant mosquitoes when new, knocking down all mosquitoes. However, bioefficacy declined over time with Olyset Plus knocking down 45.72% (95% CI: 22.84–68.62%, P ¼ 0.021) and Permanent 3.0 knocking down 78.57% (95% CI: 63.57–93.58%, P < 0.001) after 25 months. Here we demonstrate that both Olyset Plus and PermaNet 3.0 are as durable as their pyrethroid-only equivalents and had superior bioefficacy against pyrethroid-resistant An. gambiae. However, the superiority of PBO-LLINs decreased with operational use, correlating with a reduction in total PBO content. This decline in bioefficacy after just two years is concerning and there is an urgent need to assess the durability of PBO LLINs in other settings.
| Item Type: | Article |
|---|---|
| Subjects: | QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control QX Parasitology > Insects. Other Parasites > QX 650 Insect vectors WA Public Health > Preventive Medicine > WA 110 Prevention and control of communicable diseases. Transmission of infectious diseases WA Public Health > WA 20.5 Research (General) WA Public Health > Preventive Medicine > WA 240 Disinfection. Disinfestation. Pesticides (including diseases caused by) |
| Faculty: Department: | Biological Sciences > Vector Biology Department |
| Digital Object Identifer (DOI): | https://doi.org/10.1016/j.crpvbd.2022.100092 |
| Depositing User: | Luciene Salas Jennings |
| Date Deposited: | 28 Sep 2022 12:31 |
| Last Modified: | 13 Jun 2023 14:58 |
| URI: | https://archive.lstmed.ac.uk/id/eprint/21218 |
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