Chair of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 46A Kreutzwaldi St., 51006 Tartu, Estonia.
Dis Aquat Organ. 2022 Sep 15;151:37-49. doi: 10.3354/dao03688.
Global climate change is altering the abundance and spread of many aquatic parasites and pathogens. Proliferative kidney disease (PKD) of salmonids caused by the myxozoan Tetracapsuloides bryosalmonae is one such emerging disorder, and its impact is expected to increase with rising water temperature. Yet, the distribution and prevalence of T. bryosalmonae in Northern Europe remain poorly characterized. Here, we studied 43 locations in 27 rivers in northernmost Norway and Finland to describe T. bryosalmonae infection frequency and patterns in 1389 juvenile salmonids. T. bryosalmonae was discovered in 12 out of 27 rivers (44%) and prevalence ranged from 4.2 to 55.5% in Atlantic salmon and from 5.8 to 75% in brown trout among infected rivers. In sympatric populations, brown trout was more frequently infected with T. bryosalmonae than was salmon. Age-specific parasite prevalence patterns revealed that in contrast to lower latitudes, the infection of juvenile fish predominantly occurs during the second summer or later. Temperature monitoring over 2 yr indicated that the mean water temperature in June was 2.1 to 3.2°C higher in rivers containing T. bryosalmonae compared to parasite-free rivers, confirming the important role of temperature in parasite occurrence. Temporal comparison in T. bryosalmonae prevalence over a 10 yr period in 11 rivers did not reveal any signs of contemporary parasite spread to previously uninfected rivers. However, the wide distribution of T. bryosalmonae in rivers flowing to the Barents Sea indicates that climate change and heat waves may cause new disease outbreaks in northern regions.
全球气候变化正在改变许多水生寄生虫和病原体的丰度和分布。鲑鱼多房棘球蚴病（PKD）是由粘孢子虫 Tetracapsuloides bryosalmonae 引起的一种新出现的疾病，预计随着水温升高，其影响将会增加。然而，在北欧，T. bryosalmonae 的分布和流行情况仍未得到充分描述。在这里，我们研究了挪威最北部和芬兰的 27 条河流中的 43 个地点，以描述 1389 条幼鲑鱼中 T. bryosalmonae 的感染频率和模式。在 27 条河流中的 12 条（44%）发现了 T. bryosalmonae，在感染河流中，大西洋鲑的流行率范围为 4.2%至 55.5%，而褐鳟的流行率范围为 5.8%至 75%。在同域种群中，褐鳟感染 T. bryosalmonae 的频率高于鲑鱼。年龄特异性寄生虫流行模式表明，与低纬度地区不同，幼鱼的感染主要发生在第二个夏季或之后。两年的温度监测表明，在含有 T. bryosalmonae 的河流中，6 月的平均水温比无寄生虫的河流高 2.1 至 3.2°C，这证实了温度在寄生虫出现中的重要作用。在 11 条河流中，对 T. bryosalmonae 流行率进行了 10 年的时间比较，没有发现任何迹象表明寄生虫正在向以前未感染的河流传播。然而，T. bryosalmonae 在流向巴伦支海的河流中的广泛分布表明，气候变化和热浪可能会导致北部地区出现新的疾病爆发。
