Rolandsen Christer M, Madslien Knut, Ytrehus Bjørnar, Hamnes Inger Sofie, Solberg Erling J, Mysterud Atle, Vikøren Turid, Våge Jørn, Hanssen Oddvar, Miller Andrea L
Norwegian Institute for Nature Research (NINA), PO Box 5685 Sluppen, NO-7485, Trondheim, Norway.
Norwegian Veterinary Institute, P.O. Box 750 Sentrum, NO-0106, Oslo, Norway.
Int J Parasitol Parasites Wildl. 2021 Apr 27;15:120-126. doi: 10.1016/j.ijppaw.2021.04.012. eCollection 2021 Aug.
High host density combined with climate change may lead to invasion of harmful parasites in cervid (host) populations. Bot flies (Diptera: Oestridae) are a group of ectoparasites that may have strong impact on their hosts, but data on the current distribution, prevalence and intensity of the moose nose bot fly () in Scandinavia are lacking. We estimated prevalence and intensity of nose bot fly larvae in 30 moose from southern and 79 moose from central Norway. All larvae detected were identified as the moose nose bot fly. We found surprisingly high prevalence in these areas, which are up to 1300 km south-southwest of the first published location in Norway and west of the distribution in Sweden. Prevalence (0.44-1.00) was higher in areas with higher moose density. Parasite intensity in hunter killed moose was higher in central Norway (mean 5.7) than southern Norway (mean 2.9), and in both regions higher in calves and yearlings than adults. Fallen moose had higher parasite intensity (mean 9.8) compared to hunter killed moose in the subsample from central Norway, suggesting a link to host condition or behavior. Our study provides evidence of parasite range expansion, and establishing monitoring appears urgent to better understand impact on host populations.
高宿主密度与气候变化相结合可能导致有害寄生虫侵入鹿类（宿主）种群。胃蝇（双翅目：狂蝇科）是一类外寄生虫，可能对其宿主产生强烈影响，但在斯堪的纳维亚半岛，关于驼鹿鼻胃蝇（ ）的当前分布、流行率和感染强度的数据尚缺。我们估计了挪威南部30头驼鹿和中部79头驼鹿鼻胃蝇幼虫的流行率和感染强度。所有检测到的幼虫均被鉴定为驼鹿鼻胃蝇。我们发现在这些地区流行率高得出奇，这些地区位于挪威首次公布地点西南偏南达1300公里处，且在瑞典分布范围以西。在驼鹿密度较高的地区，流行率（0.44 - 1.00）更高。在挪威中部，猎人捕杀的驼鹿体内的寄生虫感染强度（平均5.7）高于挪威南部（平均2.9），并且在这两个地区，幼鹿和一岁龄鹿的感染强度均高于成年鹿。在挪威中部的子样本中，与猎人捕杀的驼鹿相比，倒地死亡的驼鹿寄生虫感染强度更高（平均9.8），这表明与宿主状况或行为存在关联。我们的研究提供了寄生虫分布范围扩大的证据，并且开展监测对于更好地了解其对宿主种群的影响显得紧迫。
