在肯尼亚西部进行1.5年现场使用后，经PBO-拟除虫菊酯增效剂处理的蚊帐和仅含拟除虫菊酯的长效驱虫蚊帐的物理完整性及残余生物效能

Physical integrity and residual bio-efficacy of PBO-pyrethroid synergist-treated and pyrethroid-only LLINs after 1.5 years of field use in Western Kenya.

作者信息

Oyweri Job, Onyango Patrick O, Machani Maxwell G, Bungei Josephat, Afrane Yaw A, Lee Ming-Chieh, Zhong Daibin, Zhou Guofa, Atieli Harrysone, Githure John, Yan Guiyun

机构信息

Department of Zoology, Maseno University, Kisumu Kenya.

International Centre of Excellence for Malaria Research, Tom Mboya University, Homabay, Kenya.

出版信息

PLoS One. 2025 Aug 12;20(8):e0330177. doi: 10.1371/journal.pone.0330177. eCollection 2025.

DOI:10.1371/journal.pone.0330177

PMID:40794684

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC12342266/

Abstract

BACKGROUND

Long-lasting insecticidal nets (LLINs) are vital for malaria control in sub-Saharan Africa, but their durability is challenged by fabric decay and pyrethroid resistance. This study assessed the physical integrity and bioefficacy of piperonyl butoxide-LLINs (PBO-LLINs) and pyrethroid-only LLINs (pyrethroid-LLINs) after 1.5 years of use in western Kenya, where resistance is widespread.

METHODS

A survey on net integrity and insecticide efficacy was conducted in randomly selected households (101-107 per group per visit) from three villages per net type group in Muhoroni Sub-County, Kisumu County. Physical integrity surveys were done after every six months while residual bio-efficacy was after every three months for 18 months. Physical integrity and residual bio-efficacy studies were conducted following WHO guidelines.

RESULTS

PBO-LLINs exhibited higher physical integrity than pyrethroid-LLINs over time. At 18 months, 45.2% (61/135) of pyrethroid-LLINs and 21.8% (31/142) of PBO-LLINs were torn, with pHI values of 2494.1 ± 1696.4 and 1618.6 ± 1056.7, respectively. Net type, net age and house wall structures significantly influenced net integrity (p < 0.05). Torn nets were significantly more common in pyrethroid-LLIN households with mud-unplastered [OR=5.323 (95% CI = 1.685-16.816), p = 0.004] and corrugated iron walls [OR=6.31 (95% CI = 2.10-18.93), p < 0.001] and in PBO-LLIN households with mud-unplastered walls [OR=9.823 (95% CI = 1.487-64.898), p = 0.018]. Against the Kisumu susceptible Anopheles gambiae s.s, both net types decreased in mortality at baseline (when new) from 97.6% to 18.4% and 98.6% to 18.5% for pyrethroid and PBO-LLINs respectively at 18 months. Against a Bungoma pyrethroid-resistant Anopheles gambiae s.s, mosquito mortality with pyrethroid-LLINs declined from 36.9% when new to 6.8% at 18 months, while PBO-LLINs dropped from 55.6% to 11.8%.

CONCLUSION

Both physical integrity and bioefficacy of LLINs declined significantly within 18 months. The findings demonstrate that not all nets in the field offer maximum protection by this time point, calling for net care education and further evaluation of PBO-LLINs especially in pyrethroid-resistant regions.

摘要

背景

长效驱虫蚊帐（LLINs）对撒哈拉以南非洲地区的疟疾防控至关重要，但其耐用性受到织物腐烂和拟除虫菊酯抗性的挑战。本研究评估了增效醚长效驱虫蚊帐（PBO-LLINs）和仅含拟除虫菊酯长效驱虫蚊帐（拟除虫菊酯-LLINs）在肯尼亚西部使用1.5年后的物理完整性和生物效力，该地区抗性普遍存在。

方法

在基苏木县穆霍罗尼分区每个蚊帐类型组的三个村庄中，对随机选择的家庭（每次访问每组101-107户）进行蚊帐完整性和杀虫剂效力调查。每六个月进行一次物理完整性调查，每三个月进行一次残留生物效力调查，为期18个月。物理完整性和残留生物效力研究按照世界卫生组织指南进行。

结果

随着时间推移，PBO-LLINs的物理完整性高于拟除虫菊酯-LLINs。在18个月时，拟除虫菊酯-LLINs的45.2%（61/135）和PBO-LLINs的21.8%（31/142）被撕裂，pHI值分别为2494.1±1696.4和1618.6±1056.7。蚊帐类型、蚊帐使用年限和房屋墙壁结构对蚊帐完整性有显著影响（p<0.05）。在拟除虫菊酯-LLINs家庭中，未抹灰泥的泥墙[比值比（OR）=5.323（95%置信区间（CI）=1.685-16.816），p=0.004]和波纹铁墙[OR=6.31（95%CI=2.10-18.93），p<0.001]以及在PBO-LLINs家庭中未抹灰泥的泥墙[OR=9.823（95%CI=1.487-64.898），p=0.018]的撕裂蚊帐明显更常见。对于基苏木易感冈比亚按蚊，两种蚊帐类型在基线时（新蚊帐时）的死亡率分别从97.6%降至18个月时的18.4%（拟除虫菊酯-LLINs）和从98.6%降至18.5%（PBO-LLINs）。对于邦戈马拟除虫菊酯抗性冈比亚按蚊，拟除虫菊酯-LLINs的蚊虫死亡率从新蚊帐时的36.9%降至18个月时的6.8%，而PBO-LLINs从55.6%降至11.8%。