Aklilu Esayas, Gebresilassie Araya, Yared Solomon, Kindu Mizan, Tekie Habte, Balkew Meshesha, Warburg Alon, Hailu Asrat, Gebre-Michael Teshome
Department of Biology, Mada Walabu University, Bale-Robe, Ethiopia.
Department of Biology, Jigjiga University, Jigjiga, Ethiopia.
PLoS One. 2017 Apr 6;12(4):e0175308. doi: 10.1371/journal.pone.0175308. eCollection 2017.
Visceral leishmaniasis (VL) also known as kala-azar is a growing health problem in Ethiopia with an estimated annual VL incidence between 3700 and 7400. The disease is mainly endemic in northwestern parts of the country. The aim of the current study was to determine the sand fly fauna and ecology of Phlebotomus orientalis in two endemic and ecologically distinct areas of northwestern Ethiopia.
Sand flies were collected using CDC light traps, sticky traps and pyrethrum spray catches from peri-domestic, mixed forest, farm field and indoor habitats from both Libo-Kemkem (May 2011-April 2012) and Metema (October 2012-September 2013) districts.
A total of 51,411 sand fly specimens were collected and identified (10,776 from highland and 40, 635 from the lowland areas). Seven species were found in the highland area: two Phlebotomus spp. (P. orientalis and P. rodhaini) and five Sergentomyia species. Whereas 19 species were found in the lowland area: six Phlebotomus (P. orientalis, P. rodhaini, P. bergeroti, P. duboscqi, P. papatasi and P. martini) and 13 Sergentomyia species. Of the Phlebotomus spp., P. orientalis was the predominant species in both the highland (99.9%) and lowland (93.7%) areas. Indoor collections using pyrethrum spray catches and sticky traps indicated that P. orientalis has a strong exophilic and exophagic behaviors in both districts. In both areas, this species showed seasonal occurrence and showing abundance during the dry months (March-May/June) of the year and increasing in numbers till the rain season, when numbers dropped dramatically. Mean density of P. orientalis in the two areas had positive and significant correlation with mean temperature in light trap collections (P<0.05). However, mean density of P. orientalis in the two areas in sticky trap collections had positive and insignificant association with the temperature (P>0.05). Regarding the rainfall pattern, density of P. orientalis had negative and statistically insignificant correlation (for light trap collections for both areas) and significant correlation (for sticky trap collections for lowland area).
The current study indicated the variation in sand fly fauna between the highland and lowland districts, wherein, P. orientalis was found to be the most abundant Phlebotomus species. The study also determined that P. orientalis exhibits distinct seasonality, where its abundance increases during the dry season and disappears when the rainy period starts in both study areas. This entomological observation on the bionomics of P. orientalis provides significant evidence for considering vector control or preventive measures in the areas studied.
内脏利什曼病（VL）又称黑热病，在埃塞俄比亚是一个日益严重的健康问题，估计每年的VL发病率在3700至7400例之间。该病主要流行于该国西北部地区。本研究的目的是确定埃塞俄比亚西北部两个流行且生态不同地区的白蛉种类及东方白蛉的生态学特征。
在利博-凯姆凯姆（2011年5月至2012年4月）和梅特马（2012年10月至2013年9月）两个地区，使用疾控中心诱蚊灯诱捕器、粘捕器和除虫菊酯喷雾捕捉法，从家庭周边、混交林、农田和室内栖息地采集白蛉。
共采集并鉴定了51411只白蛉标本（10776只来自高地，40635只来自低地）。在高地地区发现了7个种类：2种白蛉属（东方白蛉和罗得西亚白蛉）和5种司蛉属。而在低地地区发现了19个种类：6种白蛉（东方白蛉、罗得西亚白蛉、伯杰氏白蛉、杜氏白蛉、巴氏白蛉和马氏白蛉）和13种司蛉属。在白蛉属中，东方白蛉是高地（99.9%）和低地（93.7%）地区的优势种类。使用除虫菊酯喷雾捕捉法和粘捕器进行的室内采集表明，东方白蛉在两个地区都具有强烈的嗜外性和外食性。在两个地区，该种类都呈现季节性出现，在一年中的干燥月份（3月至5月/6月）数量较多，直到雨季开始时数量急剧下降。两个地区东方白蛉的平均密度与诱蚊灯诱捕法中的平均温度呈正相关且具有显著性（P<0.05）。然而，两个地区粘捕器采集的东方白蛉平均密度与温度呈正相关但无显著性（P>0.05）。关于降雨模式，东方白蛉的密度与诱蚊灯诱捕法（两个地区）呈负相关且无统计学意义，与低地地区粘捕器采集呈显著相关。
本研究表明高地和低地地区白蛉种类存在差异，其中东方白蛉是最丰富的白蛉种类。研究还确定东方白蛉表现出明显的季节性，在两个研究地区，其数量在旱季增加，雨季开始时消失。对东方白蛉生物学特性的这一昆虫学观察为在所研究地区考虑病媒控制或预防措施提供了重要证据。
