A survey of Anopheles species composition and insecticide resistance on the island of Bubaque, Bijagos Archipelago, Guinea-Bissau
A survey of Anopheles species composition and insecticide resistance on the island of Bubaque, Bijagos Archipelago, Guinea-Bissau
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DOI：
10.1186/s12936-020-3115-1
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发表时间：
2020-01-15
期刊：
影响因子：
3
通讯作者：
Logan, James G.
中科院分区：
文献类型：
--
作者：
Ant, Thomas;Foley, Erin;Logan, James G.
背景资料：布巴克是比热戈斯群岛人口最多的岛屿，比热戈斯群岛是一组疟疾流行的岛屿，位于西非几内亚比绍海岸。Bubaque的疟疾病媒控制几乎完全依靠使用长效驱虫蚊帐。然而，当地的媒介生物学特性和杀虫剂resistance.Methods：蚊子种类组成的调查进行了调查，在雨季（6月/7月）和旱季（11月/12月）开始。采用室内成虫灯诱法和幼虫浸渍法进行取样。用TaqMan PCR方法对按蚊进行种间鉴定和kdr等位基因频率测定。通过CSP-ELISA分析雌性动物的子孢子阳性。结果：发现冈比亚按蚊对氯菊酯和顺式氯氰菊酯的抗性均属于广义冈比亚按蚊（Anopheles gambiae lato（s.l.）复杂，包括一个。严格意义上的冈比亚按蚊（Anopheles gambiae sensu stricto）、科氏按蚊（Anopheles coluzzii）、黑按蚊（Anopheles melas）和按蚊（An.冈比亚/安coluzzii混血嗜内按蚊的种类组成和丰度呈明显的季节性变化，以嗜内按蚊为主。冈比亚（50%的成年人收集）在6月/7月，而一个。11月/12月黑胸蚜占优势（83.9%）。冈比亚按蚊在两个季节的子孢子率最高，6/7月和11/12月的感染率分别为13.9%和20%。西非kdr等位基因的中等频率被发现在安。gambiae（36%）、An. coluzzii（35%）、安氏按蚊（An.冈比亚/安coluzzii杂种（42%）。生物测定表明中度耐甲氯氰菊酯，但完全敏感的氯菊酯。结论：Bubaque岛保持一个安。冈比亚公司人口在6月/7月和11月/12月。冈比亚按蚊是雨季开始时的主要媒介，而安。melas可能是大多数旱季传播的原因。存在中等kdr等位基因频率，并且kdr分析表明可能存在代谢抵抗，这可能降低LLIN的疗效。这些岛屿今后的疟疾控制应考虑到蚊子种类的季节性变化，并应持续监测杀虫剂的抗药性。
Background: Bubaque is the most populous island of the Bijagos archipelago, a group of malaria-endemic islands situated off the coast of Guinea-Bissau, West Africa. Malaria vector control on Bubaque relies almost exclusively on the use of long-lasting insecticidal nets (LLINs). However, there is little information on local vector bionomics and insecticide resistance.Methods: A survey of mosquito species composition was performed at the onset of the wet season (June/July) and the beginning of the dry season (November/December). Sampling was performed using indoor adult light-traps and larval dipping. Anopheles mosquitoes were identified to species level and assessed for kdr allele frequency by TaqMan PCR. Females were analysed for sporozoite positivity by CSP-ELISA. Resistance to permethrin and alpha-cypermethrin was measured using the CDC-bottle bioassay incorporating the synergist piperonyl-butoxide.Results: Several Anopheles species were found on the island, all belonging to the Anopheles gambiae sensu lato (s.l.) complex, including An. gambiae sensu stricto, Anopheles coluzzii, Anopheles melas, and An. gambiae/An. coluzzii hybrids. Endophagic Anopheles species composition and abundance showed strong seasonal variation, with a majority of An. gambiae (50% of adults collected) caught in June/July, while An. melas was dominant in November/December (83.9% of adults collected). Anopheles gambiae had the highest sporozoite rate in both seasons, with infection rates of 13.9% and 20% in June/July and November/December, respectively. Moderate frequencies of the West African kdr allele were found in An. gambiae (36%), An. coluzzii (35%), An. gambiae/An. coluzzii hybrids (42%). Bioassays suggest moderate resistance to alpha-cypermethrin, but full susceptibility to permethrin.Conclusions: The island of Bubaque maintained an An. gambiae s.l. population in both June/July and November/December. Anopheles gambiae was the primary vector at the onset of the wet season, while An. melas is likely to be responsible for most dry season transmission. There was moderate kdr allele frequency and synergist assays suggest likely metabolic resistance, which could reduce the efficacy of LLINs. Future control of malaria on the islands should consider the seasonal shift in mosquito species, and should employ continuous monitoring for insecticide resistance.