Zemene Endalew, Belay Denekew Bitew, Tiruneh Abebaw, Lee Ming-Chieh, Yewhalaw Delenasaw, Yan Guiyun
School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.
Department of Statistics, College of Science, Bahir Dar University, Bahir Dar, Ethiopia.
BMC Infect Dis. 2021 Aug 28;21(1):882. doi: 10.1186/s12879-021-06592-9.
Understanding the behaviour of local malaria vectors is essential as effectiveness of the commonly used vector-targeted malaria control tools heavily relies on behaviour of the major malaria vectors. This study was conducted to determine species composition, biting behaviour, host preference and infectivity of anopheline mosquitoes, and assess utilization of insecticide-treated nets (ITNs) in a low transmission setting in Southwest Ethiopia.
Adult anopheline mosquitoes were collected using human landing catches (HLCs), Centers for Disease Control and Prevention (CDC) light traps (LTs) and Pyrethrum Spray Catches (PSCs) from June 2016 to May 2018 in Kishe, Jimma Zone, Southwest Ethiopia. The anopheline mosquitoes were morphologically identified. Moreover, sub-sample of An. gambiae s.l. was identified to species using polymerase chain reaction (PCR). Circum-sporozoite proteins (CSPs) and blood meal sources of the anopheline mosquitoes were tested using enzyme-linked immunosorbent assay (ELISA). In addition, a cross-sectional survey was conducted to assess ITN utilization by the inhabitants.
A total of 3659 anopheline mosquitoes comprising An. coustani complex (84.4%), An. gambiae s.l. (11.3%), and An. pharoensis and An. squamosus comprising less than 5% were collected. The anopheline mosquitoes showed marked outdoor (67%) and early evening (63%) biting behaviour. An. coustani complex and An. gambiae s.l. were predominantly zoophilic and anthropophilic, respectively. None of the sampled anopheline were CSP-positive. Most of the households (97.8%) owned at least one ITN, with modest usage by the inhabitants (73.4%). ITN usage was significantly higher among under-five children (AOR = 7.9, 95% CI: 4.41-14.03), household heads and spouses (AOR = 4.8, 95% CI: 3.0-7.59), those with sufficient access to ITNs (AOR = 1.8, 95% CI: 1.39-2.35), and who were not utilizing alternative mosquito repellents (AOR = 2.2, 95% CI: 1.58-2.99).
The anopheline mosquito species exhibited predominantly outdoor and early evening biting activity. Household ITN coverage was high with slight gap in usage. Vector control interventions should target outdoor and early biting vectors to further suppress the local mosquito population. Moreover, sensitization of the community on consistent use of ITNs is required.
了解当地疟疾病媒的行为至关重要，因为常用的以病媒为目标的疟疾控制工具的有效性在很大程度上依赖于主要疟疾病媒的行为。本研究旨在确定埃塞俄比亚西南部低传播地区按蚊的种类组成、叮咬行为、宿主偏好和感染性，并评估杀虫剂处理蚊帐（ITN）的使用情况。
2016年6月至2018年5月，在埃塞俄比亚西南部吉马州基舍，使用人饵诱捕法（HLC）、疾病控制和预防中心（CDC）诱蚊灯（LT）和除虫菊酯喷雾捕获法（PSC）收集成年按蚊。对按蚊进行形态学鉴定。此外，使用聚合酶链反应（PCR）对冈比亚按蚊复合组的子样本进行种类鉴定。使用酶联免疫吸附测定（ELISA）检测按蚊的环子孢子蛋白（CSP）和血餐来源。此外，还进行了一项横断面调查，以评估居民对ITN的使用情况。
共收集到3659只按蚊，包括库斯塔尼按蚊复合组（84.4%）、冈比亚按蚊复合组（11.3%），以及占比不到5%的法老按蚊和鳞斑按蚊。按蚊表现出明显的室外叮咬行为（67%）和傍晚早期叮咬行为（63%）。库斯塔尼按蚊复合组和冈比亚按蚊复合组分别主要偏好叮咬动物和人类。所采集的按蚊均未检测出CSP阳性。大多数家庭（97.8%）至少拥有一顶ITN，居民的使用率适中（73.4%）。五岁以下儿童（调整后比值比[AOR]=7.9，95%置信区间[CI]：4.41-14.03）、户主及其配偶（AOR=4.8，95%CI：3.0-7.59）、有足够机会获得ITN的人群（AOR=1.8，95%CI：1.39-2.35）以及未使用其他驱蚊剂的人群（AOR=2.2，95%CI：1.58-2.99）的ITN使用率显著更高。
按蚊种类主要表现出室外和傍晚早期的叮咬活动。家庭ITN覆盖率较高，但在使用方面存在细微差距。病媒控制干预措施应针对室外和早期叮咬的病媒，以进一步抑制当地蚊虫数量。此外，需要提高社区对持续使用ITN的认识。
