National Institute of Biomedical Research, PO Box 1192, Kinshasa, Democratic Republic of the Congo.
National Malaria Control Programme, Kinshasa, Democratic Republic of the Congo.
Malar J. 2018 Mar 27;17(1):129. doi: 10.1186/s12936-018-2285-6.
Globally, the Democratic Republic of Congo (DRC) accounted for 9% of malaria cases and 10% of malaria deaths in 2015. As part of control efforts, more than 40 million long-lasting insecticidal nets (LLINs) were distributed between 2008 and 2013, resulting in 70% of households owning one or more LLINs in 2014. To optimize vector control efforts, it is critical to monitor vector behaviour and insecticide resistance trends. Entomological data was collected from eight sentinel sites throughout DRC between 2013 and 2016 in Kingasani, Mikalayi, Lodja, Kabondo, Katana, Kapolowe, Tshikaji and Kalemie. Mosquito species present, relative densities and biting times were monitored using human landing catches (HLC) conducted in eight houses, three times per year. HLC was conducted monthly in Lodja and Kapolowe during 2016 to assess seasonal dynamics. Laboratory data included resistance mechanism frequency and sporozoite rates. Insecticide susceptibility testing was conducted with commonly used insecticides including deltamethrin and permethrin. Synergist bioassays were conducted with PBO to determine the role of oxidases in permethrin resistance.
In Lodja, monthly Anopheles gambiae s.l. biting rates were consistently high at > 10 bites/person/night indoors and outdoors. In Kapolowe, An. gambiae s.l. dominated during the rainy season, and Anopheles funestus s.l. during the dry season. In all sites, An. gambiae and An. funestus biting occurred mostly late at night. In Kapolowe, significant biting of both species started around 19:00, typically before householders use nets. Sporozoite rates were high, with a mean of 4.3% (95% CI 3.4-5.2) for An. gambiae and 3.3% (95% CI 1.3-5.3) for An. funestus. Anopheles gambiae were resistant to permethrin in six out of seven sites in 2016. In three sites, susceptibility to deltamethrin was observed despite high frequency permethrin resistance, indicating the presence of pyrethroid-specific resistance mechanisms. Pre-exposure to PBO increased absolute permethrin-associated mortality by 24%, indicating that resistance was partly due to metabolic mechanisms. The kdr-1014F mutation in An. gambiae was present at high frequency (> 70%) in three sites (Kabondo, Kingasani and Tshikaji), and lower frequency (< 20%) in two sites (Lodja and Kapolowe).
The finding of widespread resistance to permethrin in DRC is concerning and alternative insecticides should be evaluated.
2015 年，全球范围内刚果民主共和国（DRC）占疟疾病例的 9%，疟疾死亡人数的 10%。作为控制工作的一部分，2008 年至 2013 年间分发了超过 4000 万顶长效驱虫蚊帐（LLIN），结果 2014 年 70%的家庭拥有一顶或多顶 LLIN。为了优化病媒控制工作，监测病媒行为和杀虫剂耐药性趋势至关重要。2013 年至 2016 年间，在金加萨尼、米卡莱伊、洛贾、卡邦多、卡塔纳、卡波洛韦、奇卡吉和卡莱米的八个哨兵点收集了昆虫学数据。在八个家庭中使用人体诱捕器（HLC）监测存在的蚊子种类、相对密度和叮咬时间，每年监测三次。2016 年，洛贾和卡波洛韦每月进行 HLC，以评估季节性动态。实验室数据包括耐药机制频率和孢子虫率。使用常用杀虫剂，包括氯菊酯和氯氰菊酯，进行了杀虫剂敏感性测试。使用增效醚进行协同生物测定，以确定氧化酶在氯氰菊酯耐药性中的作用。
在洛贾，每月按蚊叮咬率始终很高，室内和室外均超过 10 次/人/夜。在卡波洛韦，按蚊在雨季占主导地位，而在旱季，冈比亚按蚊占主导地位。在所有地点，按蚊和冈比亚按蚊叮咬大多发生在深夜。在卡波洛韦，两种蚊子的叮咬都在 19 点左右开始，通常在户主使用蚊帐之前。孢子虫率很高，冈比亚按蚊的平均值为 4.3%（95%置信区间 3.4-5.2），冈比亚按蚊为 3.3%（95%置信区间 1.3-5.3）。2016 年，在七个地点中的六个地点，按蚊对氯菊酯具有抗药性。在三个地点，尽管氯菊酯耐药率很高，但对氯菊酯的敏感性观察到，表明存在拟除虫菊酯特异性耐药机制。预先接触 PBO 可使绝对氯氰菊酯相关死亡率增加 24%，表明耐药性部分归因于代谢机制。在三个地点（卡邦多、金加萨尼和奇卡吉），发现了高频率 (>70%)的 kdr-1014F 突变，而在两个地点（洛贾和卡波洛韦），该突变的频率较低 (<20%)。
在 DRC 发现广泛的氯菊酯耐药性令人担忧，应评估替代杀虫剂。
