Distribution and prevalence of the myxozoan parasite Tetracapsuloides bryosalmonae in northernmost Europe: analysis of three salmonid species

Abstract

Global warming has a profound impact on the geographical expansion, abundance and virulence of many pathogens (Kutz et al. 2009, Callaway et al. 2012, Gallana et al. 2013, and temperature-driven environmental stress may further increase the risk of disease (Marcogliese 2008, Niinemets et al. 2017. The impact of global warming has been particularly severe in polar regions (Post et al. 2019, Previdi et al.

Spatial and intra‐host distribution of myxozoan parasite Tetracapsuloides bryosalmonae among Baltic sea trout (Salmo trutta)

“…For 230 specimens, DNA was extracted using the QIAamp 96 DNA QIAcube HT kit and QIAcube® HT Instrument for automated nucleic acid purification (QIAGEN). For 65 specimens, DNA was extracted using a one‐step Chelex double‐stranded DNA extraction protocol (Casquet et al, 2011; Lauringson et al, 2022). The quality and quantity of DNA was measured using a NanoDrop™ 2000 spectrophotometer (Thermo Scientific).…”

“…The quality and quantity of DNA was measured using a NanoDrop™ 2000 spectrophotometer (Thermo Scientific). Following DNA extraction, multiplex PCR was conducted as in Lauringson et al (2022), using T. bryosalmonae‐ specific primers described in Dash and Vasemägi (2014). This multiplex reaction amplifies 2–3 parasite (166, 298 and 756 bp) and a single salmonid‐specific fragment (ca 500 bp).…”

“…PKD primarily affects juvenile salmonids during their first growth season in freshwater habitat (Dash & Vasemägi, 2014; Mo et al, 2011; Schager et al, 2007). Infections can also occur among older fish who have not been previously exposed to the parasite (Feist & Longshaw, 2006; Lauringson et al, 2022). However, compared with young‐of‐the‐year fish, older specimens are typically less susceptible to the disease (Bailey et al, 2021).…”

“…However, considerably fewer studies have analysed the prevalence and distribution of T. bryosalmonae at older life stages of salmonid fish. For example, recent work in Northern Norway demonstrated that brown trout and Atlantic salmon become infected by T. bryosalmonae after the first growing season (Lauringson et al, 2022). Similarly, Dash and Vasemägi (2014) found higher T. bryosalmonae prevalence among 1+ and older anadromous brown trout compared with 0+ fish, indicating that the (re)infections may also occur after the first growing season.…”