Research: Food Safety and Animal Health, Norwegian Veterinary Institute, Stakkevollvegen 23b, 9010, Tromsø, Norway.
Finnish Food Authority (FINPAR), Oulu, Finland.
Acta Vet Scand. 2020 May 27;62(1):24. doi: 10.1186/s13028-020-00524-4.
Sami reindeer herders have considerable traditional knowledge about a neurological reindeer disease resembling elaphostrongylosis, but the causative agent was not identified prior to the description of the brainworm Elaphostrongylus rangiferi in Russia in 1958. Elaphostrongylosis was quickly recognised as a serious cause of reindeer morbidity and mortality. The ecology, epidemiology and pathophysiology of the disease were studied in Sweden and Norway during the 1960s and in particular the 1970s to 1990s. In Finland, elaphostrongylosis was not recognised as an important disease for Finnish reindeer husbandry, even though the presence of brainworm infection has been documented. Brainworm has an indirect lifecycle with snail and slug intermediate hosts. The free-living L1 larvae have extremely good freeze tolerance and can survive > 360 days at - 80 °C in water (solid ice). Even though reindeer brainworm is clearly well adapted to the Arctic chill, the lifecycle stages outside the reindeer final host are sped up at warmer environmental temperatures. Arctic summer temperatures are close to the developmental threshold of the parasite in the intermediate gastropod hosts (8-10 °C), and the parasite has typically had a 2-year life cycle. Disease outbreaks generally occur during the winter following the infection of reindeer with infected snails and slugs during the summer and autumn. Warmer summers result in faster development of brainworm larvae in the intermediate hosts. Clinical symptoms have been seen reported as early as August, such as in the outbreak in Trøndelag, Norway in 2018. The reindeer brainworm is also a cause of conflict between reindeer herders and small ruminant farmers, because it can cause severe disease in goats and sheep, which share pasture with reindeer. Many knowledge gaps remain if we wish to successfully predict and mitigate for large-scale outbreaks in a future with a predicted warmer, wetter and wilder climate.
萨米驯鹿牧民对一种类似于旋毛虫病的神经驯鹿疾病具有相当丰富的传统知识，但在 1958 年俄罗斯描述脑蠕虫 Elaphostrongylus rangiferi 之前，尚未确定其病原体。旋毛虫病很快被认为是驯鹿发病率和死亡率的一个严重原因。20 世纪 60 年代和特别是 20 世纪 70 年代至 90 年代期间，在瑞典和挪威研究了该病的生态学、流行病学和病理生理学。在芬兰，尽管有脑蠕虫感染的记录，但旋毛虫病并未被认为是对芬兰驯鹿养殖业的重要疾病。脑蠕虫具有间接的生命周期，其中间宿主为蜗牛和鼻涕虫。自由生活的 L1 幼虫具有极强的抗冻能力，在水中（固体冰）中可存活超过 360 天，温度低至-80°C。尽管驯鹿脑蠕虫显然很好地适应了北极的严寒，但在更温暖的环境温度下，终宿主以外的生命周期阶段会加快。北极夏季的温度接近中间腹足纲宿主中寄生虫的发育阈值（8-10°C），寄生虫通常具有 2 年的生命周期。疾病爆发通常发生在夏季感染感染蜗牛和鼻涕虫的驯鹿之后的冬季。温暖的夏季导致中间宿主中脑蠕虫幼虫的发育速度加快。早在 8 月就已经有临床症状的报道，如 2018 年挪威特隆赫姆发生的疫情。驯鹿脑蠕虫也是驯鹿牧民和小反刍动物农民之间冲突的原因，因为它会导致山羊和绵羊（与驯鹿共享牧场）严重患病。如果我们希望在未来预测和减轻预测的更温暖、更潮湿和更狂野的气候下的大规模爆发，仍然存在许多知识空白。
