London School of Hygiene & Tropical Medicine, London, United Kingdom.
Centre de Recherche Entomologique de Cotonou, Cotonou, Benin.
PLoS One. 2024 Aug 29;19(8):e0298513. doi: 10.1371/journal.pone.0298513. eCollection 2024.
Pyrethroid-chlorfenapyr nets have been recommended for malaria control by the World Health Organisation (WHO) after an alpha-cypermethrin-chlorfenapyr net showed improved impact in epidemiological trials. PermaNet® Dual is a new deltamethrin-chlorfenapyr net developed by Vestergaard Sàrl to expand options to control programmes. A series of laboratory studies were performed according to WHO guidelines to assess the regeneration time, efficacy and wash-resistance of PermaNet® Dual. Regeneration time was determined by subjecting net pieces to cone bioassays and tunnel tests before and 0, 1, 2, 3, 5 and 7 days after washing. The wash-resistance of PermaNet® Dual was evaluated compared to WHO-prequalified pyrethroid-only (PermaNet® 2.0) and pyrethroid-chlorfenapyr (Interceptor® G2) nets by testing net pieces washed 0, 1, 3, 5, 10, 15 and 20 times in cone bioassays and tunnel tests. Tests were performed with susceptible and pyrethroid-resistant strains of Anopheles gambiae to assess the pyrethroid and chlorfenapyr components separately. Net pieces were also analysed to determine insecticide content. In regeneration time studies, the biological activity of the deltamethrin and chlorfenapyr components of PermaNet® Dual regenerated within one day after washing and a 1-day washing interval was adopted for wash-resistance studies. PermaNet® Dual induced high mortality (98%) and blood-feeding inhibition (98%) of the susceptible strain after 20 washes fulfilling WHO efficacy criteria in tunnel tests (≥80% mortality, ≥90% blood-feeding inhibition). Similar results were obtained with PermaNet® 2.0 (99% mortality, 99% blood-feeding inhibition) and Interceptor® G2 (99% mortality, 98% blood-feeding inhibition) washed 20 times. In wash-resistance tunnel tests against the pyrethroid-resistant strain, PermaNet® Dual washed 20 times induced high mortality (91%) and blood-feeding inhibition (73%), which was similar to Interceptor® G2 (87% mortality, 79% blood-feeding inhibition) and superior to PermaNet® 2.0 (47% mortality, 68% blood-feeding inhibition). PermaNet® Dual fulfilled WHO efficacy criteria in laboratory bioassays and showed potential to improve control of pyrethroid-resistant malaria vectors.
经世界卫生组织（WHO）推荐，在一项氯氟氰菊酯-氯菊酯网显示出在流行病学试验中提高效果后，拟除虫菊酯-氯氟氰菊酯网用于疟疾控制。PermaNet® Dual 是由 Vestergaard Sàrl 开发的一种新型氯菊酯-氯氟氰菊酯网，旨在扩大控制计划的选择。根据世界卫生组织的指导方针进行了一系列实验室研究，以评估 PermaNet® Dual 的再生时间、功效和耐洗性。通过在洗涤前和洗涤后 0、1、2、3、5 和 7 天对网片进行锥形生物测定和隧道试验，确定了再生时间。PermaNet® Dual 的耐洗性通过在锥形生物测定和隧道试验中对洗涤 0、1、3、5、10、15 和 20 次的网片进行测试，与世界卫生组织预认证的仅含拟除虫菊酯（PermaNet® 2.0）和含拟除虫菊酯和氯氟氰菊酯（Interceptor® G2）的网进行比较。用敏感和对拟除虫菊酯有抗性的冈比亚按蚊品系进行测试，分别评估拟除虫菊酯和氯氟氰菊酯成分的功效。还对网片进行了分析，以确定杀虫剂含量。在再生时间研究中，PermaNet® Dual 的氯菊酯和氯氟氰菊酯成分的生物活性在洗涤后一天内得到恢复，因此采用一天一次的洗涤间隔进行耐洗性研究。PermaNet® Dual 诱导敏感菌株在隧道试验中 20 次洗涤后达到 98%的死亡率（98%）和 98%的吸血抑制率（98%），符合世界卫生组织的功效标准（≥80%的死亡率，≥90%的吸血抑制率）。PermaNet® 2.0（99%的死亡率，99%的吸血抑制率）和 Interceptor® G2（99%的死亡率，98%的吸血抑制率）在 20 次洗涤后也得到了类似的结果。在对拟除虫菊酯抗性品系的耐洗性隧道试验中，PermaNet® Dual 洗涤 20 次后诱导的死亡率（91%）和吸血抑制率（73%）与 Interceptor® G2（87%的死亡率，79%的吸血抑制率）相似，优于 PermaNet® 2.0（47%的死亡率，68%的吸血抑制率）。PermaNet® Dual 在实验室生物测定中符合世界卫生组织的功效标准，显示出改善对拟除虫菊酯抗性疟疾媒介控制的潜力。
