National Malaria Elimination Programme, Ministry of Health Ethiopia, PO Box 1234, Addis Ababa, Ethiopia.
Aklilu Lemma Institute of Pathobiology, Addis Ababa University, PO Box 1176, Addis Ababa, Ethiopia.
Malar J. 2023 Feb 9;22(1):48. doi: 10.1186/s12936-023-04475-9.
Malaria, transmitted by the bite of infective female Anopheles mosquitoes, remains a global public health problem. The presence of an invasive Anopheles stephensi, capable of transmitting Plasmodium vivax and Plasmodium falciparum parasites was first reported in Ethiopia in 2016. The ecology of An. stephensi is different from that of Anopheles arabiensis, the primary Ethiopian malaria vector, and this suggests that alternative control strategies may be necessary. Larviciding may be an effective alternative strategy, but there is limited information on the susceptibility of Ethiopian An. stephensi to common larvicides. This study aimed to evaluate the efficacy of temephos and Bacillus thuringiensis var. israelensis (Bti) larvicides against larvae of invasive An. stephensi.
The diagnostic doses of two larvicides, temephos (0.25 ml/l) and Bti (0.05 mg/l) were tested in the laboratory against the immature stages (late third to early fourth stages larvae) of An. stephensi collected from the field and reared in a bio-secure insectary. Larvae were collected from two sites (Haro Adi and Awash Subuh Kilo). For each site, three hundred larvae were tested against each insecticide (as well as an untreated control), in batches of 25. The data from all replicates were pooled and descriptive statistics prepared.
The mortality of larvae exposed to temephos was 100% for both sites. Mortality to Bti was 99.7% at Awash and 100% at Haro Adi site.
Larvae of An. stephensi are susceptible to temephos and Bti larvicides suggesting that larviciding with these insecticides through vector control programmes may be effective against An. stephensi in these localities.
疟疾由感染性雌性按蚊叮咬传播，仍是全球公共卫生问题。2016 年，埃塞俄比亚首次报告存在能够传播间日疟原虫和恶性疟原虫的入侵性按蚊斯蒂芬斯。按蚊斯蒂芬斯的生态与主要的埃塞俄比亚疟疾传播媒介按蚊阿蚊不同，这表明可能需要替代控制策略。幼虫杀灭可能是一种有效的替代策略，但关于埃塞俄比亚按蚊斯蒂芬斯对常见幼虫杀灭剂的敏感性的信息有限。本研究旨在评估涕灭威和苏云金芽孢杆菌以色列亚种（Bti）幼虫杀灭剂对入侵性按蚊斯蒂芬斯幼虫的效果。
在实验室中，用诊断剂量的两种幼虫杀灭剂，涕灭威（0.25ml/l）和 Bti（0.05mg/l），对从野外收集并在生物安全昆虫饲养室中饲养的按蚊斯蒂芬斯的幼虫进行了测试。从两个地点（哈罗阿迪和阿瓦什苏布赫基洛）收集幼虫。每个地点用 300 只幼虫分别对每种杀虫剂（以及未处理的对照）进行测试，每次测试 25 只。将所有重复的数据合并并进行描述性统计。
接触涕灭威的幼虫死亡率为 100%，两个地点均为 100%。在阿瓦什，Bti 的死亡率为 99.7%，在哈罗阿迪的死亡率为 100%。
按蚊斯蒂芬斯的幼虫对涕灭威和 Bti 幼虫杀灭剂敏感，这表明通过病媒控制计划使用这些杀虫剂进行幼虫杀灭可能对这些地点的按蚊斯蒂芬斯有效。
