Nnko Happiness J, Ngonyoka Anibariki, Salekwa Linda, Estes Anna B, Hudson Peter J, Gwakisa Paul S, Cattadori Isabella M
School of Life Sciences and Bioengineering, The Nelson Mandela African Institution of Science and Technology, Arusha 477, Tanzania.
Department of Geography and Environmental Studies, University of Dodoma, Dodoma, Tanzania.
J Vector Ecol. 2017 Jun;42(1):24-33. doi: 10.1111/jvec.12236.
Tsetse flies, the vectors of trypanosomiasis, represent a threat to public health and economy in sub-Saharan Africa. Despite these concerns, information on temporal and spatial dynamics of tsetse and trypanosomes remain limited and may be a reason that control strategies are less effective. The current study assessed the temporal variation of the relative abundance of tsetse fly species and trypanosome prevalence in relation to climate in the Maasai Steppe of Tanzania in 2014-2015. Tsetse flies were captured using odor-baited Epsilon traps deployed in ten sites selected through random subsampling of the major vegetation types in the area. Fly species were identified morphologically and trypanosome species classified using PCR. The climate dataset was acquired from the African Flood and Drought Monitor repository. Three species of tsetse flies were identified: G. swynnertoni (70.8%), G. m. morsitans (23.4%), and G.pallidipes (5.8%). All species showed monthly changes in abundance with most of the flies collected in July. The relative abundance of G. m. morsitans and G. swynnertoni was negatively correlated with maximum and minimum temperature, respectively. Three trypanosome species were recorded: T. vivax (82.1%), T. brucei (8.93%), and T. congolense (3.57%). The peak of trypanosome infections in the flies was found in October and was three months after the tsetse abundance peak; prevalence was negatively correlated with tsetse abundance. A strong positive relationship was found between trypanosome prevalence and temperature. In conclusion, we find that trypanosome prevalence is dependent on fly availability, and temperature drives both tsetse fly relative abundance and trypanosome prevalence.
采采蝇是锥虫病的传播媒介，对撒哈拉以南非洲的公共卫生和经济构成威胁。尽管存在这些担忧，但关于采采蝇和锥虫时空动态的信息仍然有限，这可能是控制策略效果不佳的一个原因。本研究评估了2014 - 2015年坦桑尼亚马赛草原采采蝇物种相对丰度和锥虫流行率随气候的时间变化。通过对该地区主要植被类型进行随机二次抽样，在10个地点部署气味诱捕的ε型诱捕器来捕获采采蝇。通过形态学鉴定蝇类物种，并使用PCR对锥虫物种进行分类。气候数据集来自非洲洪水和干旱监测库。鉴定出三种采采蝇：斯氏舌蝇（70.8%）、刺舌蝇指名亚种（23.4%）和淡黄舌蝇（5.8%）。所有物种的丰度都呈现月度变化，大部分采采蝇在7月捕获。刺舌蝇指名亚种和斯氏舌蝇的相对丰度分别与最高温度和最低温度呈负相关。记录到三种锥虫：活泼锥虫（82.1%）、布氏锥虫（8.93%）和刚果锥虫（3.57%）。采采蝇中锥虫感染的高峰期出现在10月，比采采蝇丰度高峰期晚三个月；流行率与采采蝇丰度呈负相关。锥虫流行率与温度之间存在很强的正相关关系。总之，我们发现锥虫流行率取决于采采蝇的可获得性，温度驱动采采蝇相对丰度和锥虫流行率。
