Pidwerbesky Ashley J, Gair Carly J, Berkvens Charlene N, Bollinger Trent K, Detwiler Jillian T
Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada.
Assiniboine Park Zoo, Winnipeg, MB, Canada.
Int J Parasitol Parasites Wildl. 2023 Jan 30;21:305-312. doi: 10.1016/j.ijppaw.2023.01.009. eCollection 2023 Aug.
In North America, some moose populations are declining, and meningeal worm () infections may be contributing. Moose are aberrant hosts for meningeal worm and develop severe pathology whereas white-tailed deer (WTD) are definitive hosts that experience minimal pathology and spread parasite larvae into the environment. Analyses of harvested WTD heads confirmed meningeal worm in Western Manitoba, Canada including in areas where moose have experienced population declines and are currently of management concern. The prevalence of larval meningeal worm from WTD feces in these areas are unknown, particularly because the dorsal-spined larvae (DSL) are morphologically indistinguishable from muscle worm (). To assess transmission risk of DSL, we investigated the spatial and temporal variation of prevalence in WTD feces from four areas (two with historical moose population declines and two without) sampled across two summers. We predicted higher prevalence of DSL in areas where moose are of management concern and surveys have shown higher meningeal worm prevalence in WTD heads. Further, we expected to only recover meningeal worm, as muscle worm has only been reported from caribou in more northern areas of Manitoba. We collected WTD feces by transect sampling, used the Baermann technique to obtain larvae, and sequenced partial cytochrome oxidase 1 and internal transcribed spacer 2 genes to confirm species identity. Zero-inflated models revealed that DSL prevalence did not differ temporally but was higher in areas where moose are of management concern. Genetic analyses revealed that meningeal worm and muscle worm were both present in Western Manitoba and co-occurred in three areas. Our results reveal novel insights into the geographic distribution of muscle worm and emphasize the importance of DNA sequencing for DSL identification. We suggest that concern for moose populations is warranted given the increased risk of parasite infection in some management areas.
在北美，一些驼鹿种群数量正在下降，脑膜线虫感染可能是一个影响因素。驼鹿是脑膜线虫的异常宿主，会出现严重病变，而白尾鹿是终末宿主，病变轻微，并将寄生虫幼虫传播到环境中。对采集的白尾鹿头部进行分析，证实加拿大曼尼托巴省西部存在脑膜线虫，包括在驼鹿种群数量下降且目前受到管理关注的地区。这些地区白尾鹿粪便中幼虫型脑膜线虫的流行率尚不清楚，特别是因为背刺幼虫在形态上与肌肉线虫难以区分。为了评估背刺幼虫的传播风险，我们调查了两个夏季从四个地区（两个有历史驼鹿种群数量下降的地区和两个没有的地区）采集的白尾鹿粪便中流行率的时空变化。我们预测，在受到管理关注的驼鹿所在地区，背刺幼虫的流行率会更高，并且调查显示白尾鹿头部的脑膜线虫流行率也更高。此外，我们预计只能检测到脑膜线虫，因为肌肉线虫仅在曼尼托巴省北部地区的驯鹿中被报道过。我们通过样带采样收集白尾鹿粪便，使用贝尔曼技术获取幼虫，并对细胞色素氧化酶1和内转录间隔区2基因的部分序列进行测序以确认物种身份。零膨胀模型显示，背刺幼虫的流行率在时间上没有差异，但在受到管理关注的驼鹿所在地区更高。基因分析表明，脑膜线虫和肌肉线虫在曼尼托巴省西部均有出现，且在三个地区同时存在。我们的研究结果揭示了关于肌肉线虫地理分布的新见解，并强调了DNA测序在背刺幼虫鉴定中的重要性。我们建议，鉴于一些管理区域寄生虫感染风险增加，对驼鹿种群的关注是有必要的。
