Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Abomey-Calavi, Benin.
Centre de Recherche Entomologique de Cotonou, Cotonou, Benin.
Parasit Vectors. 2024 Jan 4;17(1):7. doi: 10.1186/s13071-023-06104-5.
Long-lasting insecticidal nets (LLINs) may have different impacts on distinct mosquito vector species. We assessed the efficacy of pyrethroid-pyriproxyfen and pyrethroid-chlorfenapyr LLINs on the density of Anopheles gambiae s.s. and An. coluzzii compared to pyrethroid-only nets in a three-arm cluster randomised control trial in Benin.
Indoor and outdoor collections of adult mosquitoes took place in 60 clusters using human landing catches at baseline and every 3 months for 2 years. After morphological identification, around 15% of randomly selected samples of An. gambiae s.l. were dissected to determine parity, species (using PCR).
Overall, a total of 46,613 mosquito specimens were collected at baseline and 259,250 in the eight quarterly collections post-net distribution. Post-net distribution, approximately 70% of the specimens of An. gambiae s.l. speciated were An. coluzzii, while the rest were mostly composed of An. gambiae s.s. with a small proportion (< 1%) of hybrids (An. gambiae/coluzzii). There was no evidence of a significant reduction in vector density indoors in either primary vector species [An. coluzzii: DR (density ratio) = 0.62 (95% CI 0.21-1.77), p = 0.3683 for the pyrethroid-pyriproxyfen LLIN and DR = 0.56 (95% CI 0.19-1.62), p = 0.2866 for the pyrethroid-chlorfenapyr LLIN, An. gambiae s.s.: DR = 0.52 (95% CI 0.18-1.46), p = 0.2192 for the pyrethroid-pyriproxyfen LLIN and DR = 0.53 (95% CI 0.19-1.46), p = 0.2222 for the pyrethroid-chlorfenapyr]. The same trend was observed outdoors. Parity rates of An. gambiae s.l. were also similar across study arms.
Compared with pyrethroid-only LLINs, pyrethroid-chlorfenapyr LLINs and pyrethroid-pyriproxyfen LLINs performed similarly against the two primary mosquito species An. gambiae s.s. and An. coluzzii in Benin.
长效杀虫蚊帐（LLINs）可能对不同的蚊虫媒介物种产生不同的影响。我们在贝宁进行了一项三臂随机对照试验，评估了拟除虫菊酯-吡丙醚和拟除虫菊酯-氯氰菊酯 LLINs 对冈比亚按蚊和库蚊的密度的影响，与仅含拟除虫菊酯的蚊帐进行了比较。
在基线和蚊帐分发后每 3 个月进行 2 年的 60 个集群的室内和室外成蚊采集，使用人体诱捕器进行。在形态学鉴定后，随机选择约 15%的冈比亚按蚊 s.l.样本进行解剖，以确定种群（使用 PCR）。
总共在基线时收集了 46613 只蚊子标本，在蚊帐分发后的 8 次季度采集中共收集了 259250 只。在蚊帐分发后，约 70%的冈比亚按蚊 s.l.物种是库蚊，其余主要是冈比亚按蚊 s.s.，只有一小部分（<1%）为杂种（冈比亚按蚊/库蚊）。在室内，主要媒介物种[库蚊：DR（密度比）= 0.62（95%CI 0.21-1.77），p=0.3683 对于拟除虫菊酯-吡丙醚 LLIN，DR=0.56（95%CI 0.19-1.62），p=0.2866 对于拟除虫菊酯-氯氰菊酯 LLIN]和冈比亚按蚊 s.s.的密度均无明显降低：DR=0.52（95%CI 0.18-1.46），p=0.2192 对于拟除虫菊酯-吡丙醚 LLIN，DR=0.53（95%CI 0.19-1.46），p=0.2222 对于拟除虫菊酯-氯氰菊酯 LLIN。在室外也观察到了同样的趋势。冈比亚按蚊 s.l.的生殖率在不同研究组之间也相似。
与仅含拟除虫菊酯的 LLINs 相比，贝宁的拟除虫菊酯-氯氰菊酯 LLINs 和拟除虫菊酯-吡丙醚 LLINs 对冈比亚按蚊 s.s.和库蚊这两种主要蚊虫的效果相似。
