Akono Patrick Ntonga, Mbida Jean Arthur Mbida, Tonga Calvin, Belong Philippe, Ngo Hondt Odette Etoile, Magne Gaëlle Tamdem, Peka Marie Florence, Lehman Leopold Gustave
Laboratory of Animal Biology, Department of Animal Biology, Faculty of Science, University of Douala, P.O. Box 2701, Douala, Cameroon.
Higher Teacher training college, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
Parasit Vectors. 2015 May 28;8:293. doi: 10.1186/s13071-015-0906-2.
The use of inland valley swamps for vegetable crop agriculture contributes to food security in urban and less urbanized settings in Africa. The impact of this agriculture on aggressive mosquitoes' diversity and malaria transmission in central Africa is poorly documented. This study is aimed at assessing the impact of vegetable crop agriculture on these entomological parameters in urban and less urbanized settings of the forest area, south of Cameroon.
The human bait technique was used for the capture of aggressive mosquitoes from January to December 2012. For three consecutive days each month, captures were performed on volunteers in hydro-agricultural and river bank sites of Akonolinga and Yaoundé. Physico-chemical characteristics of mosquito breeding sites were recorded. Molecular alongside morpho-taxonomic techniques were used for the identification of mosquito species; ELISA test was used to reveal Plasmodium falciparum infected mosquitoes through the detection of CSP. Mosquito diversity, aggressivity and malaria transmission in sites and settings were determined and compared.
Biting rates were higher in hydro-agricultural sites of less urbanized and urban settings (31.8 b/p/n and 28.6 b/p/n respectively) than in river banks sites (6.83 b/p/n and 3.64 b/p/n respectively; p < 0.0001). Physico-chemical parameters of breeding sites were not fundamentally different. Five anopheline species were identified; An. gambiae, An. funestus s.s., An. moucheti s.s., An. hancocki and An. nili s.s. In hydro-agricultural sites 2 species were captured in the urban setting versus 4 in the less urbanized setting, meanwhile in river bank sites, 3 species were captured in the urban setting versus 4 species in the less urbanized setting. An. nili s.s. was found in river banks only. An. hancocki was not found to insure Plasmodium falciparum Welch transmission. EIR in hydro-agricultural sites varied from 1.86 ib/p/n (urban area) to 2.13 ib/p/n (less urbanized area) with higher rates in April/May and August. Overall, EIR was higher in less urbanized areas (p < 0.0001) but the difference was nullified with the practice of vegetable crop agriculture (p = 0.2).
These results highlight the need for specific preventive measures that take into account the ecological peculiarities related to vegetable crop agriculture on hydro-agricultural lands, in order to protect inhabitants from malaria.
在非洲，利用内陆山谷沼泽地进行蔬菜作物种植有助于保障城市及城市化程度较低地区的粮食安全。然而，这种农业活动对中非地区侵袭性蚊子的多样性及疟疾传播的影响鲜有文献记载。本研究旨在评估蔬菜作物种植对喀麦隆南部森林地区城市及城市化程度较低地区这些昆虫学参数的影响。
采用人饵诱捕技术于2012年1月至12月捕获侵袭性蚊子。每月连续三天，在阿科诺林加和雅温得的水产农业区及河岸地区对志愿者进行诱捕。记录蚊子滋生地的理化特征。运用分子技术及形态分类技术鉴定蚊子种类；采用酶联免疫吸附测定（ELISA）试验，通过检测环子孢子蛋白（CSP）来揭示感染恶性疟原虫的蚊子。确定并比较不同地点和环境中的蚊子多样性、攻击性及疟疾传播情况。
城市化程度较低地区及城市的水产农业区的叮咬率较高（分别为31.8次/人/晚和28.6次/人/晚），高于河岸地区（分别为6.83次/人/晚和3.64次/人/晚；p<0.0001）。滋生地的理化参数并无根本差异。鉴定出五种按蚊；冈比亚按蚊、嗜人按蚊指名亚种（An. funestus s.s.）、穆氏按蚊指名亚种（An. moucheti s.s.）、汉科克按蚊（An. hancocki）和尼罗按蚊指名亚种（An. nili s.s.）。在水产农业区，城市环境中捕获到2种，而城市化程度较低的环境中捕获到4种；同时在河岸地区，城市环境中捕获到3种，城市化程度较低的环境中捕获到4种。尼罗按蚊指名亚种仅在河岸地区发现。未发现汉科克按蚊能传播恶性疟原虫。水产农业区的昆虫接种率（EIR）在城市地区为1.86感染性叮咬/人/晚，在城市化程度较低地区为2.13感染性叮咬/人/晚，4月/5月和8月的发生率较高。总体而言，城市化程度较低地区的EIR较高（p<0.0001），但蔬菜作物种植活动使这种差异消失（p = 0.2）。
这些结果凸显了采取特定预防措施的必要性，该措施应考虑到水产农业用地上蔬菜作物种植相关的生态特性，以保护居民免受疟疾侵害。
