Widespread Seropositivity to Viral Hemorrhagic Septicemia Virus (VHSV) in Four Species of Inland Sport Fishes in Wisconsin

Abstract

Serological assays were conducted for anti‐viral hemorrhagic septicemia virus (VHSV) antibodies in four species of fish in Wisconsin (Bluegill Lepomis macrochirus, Brown Trout Salmo trutta, Northern Pike Esox lucius, and Walleye Sander vitreus) to examine spatial and temporal distributions of exposure. Sera were tested for non‐neutralizing anti‐nucleocapsid antibodies to VHSV by blocking enzyme‐linked immunosorbent assay (ELISA). Results (percent inhibition [%I]) were analyzed for differences among species, across geographic distance, and among water management units. Positive fish occurred in 37 of 46 inland water bodies tested, including in water bodies far from reported outbreak events. Using highly conservative species‐specific thresholds (mean %I of presumptive uninfected fish + 2 SDs), 4.3% of Bluegill, 13.4% of Brown Trout, 19.3% of Northern Pike, and 18.3% of Walleye tested positive for VHSV antibodies by ELISA. Spatial patterns of seropositivity and changes in %I between sampling years were also analyzed. These analyses explore how serology might be used to understand VHSV distribution and dynamics and ultimately to inform fisheries management.

Five Species of Wild Freshwater Sport Fish in Wisconsin, USA, Reveal Highly Diverse Viromes

“…We analyzed 103 serum samples collected from five species of fish during a previous study of viral hemorrhagic septicemia virus ( Rhabdoviridae: Novirhabdovirus ) [ 24 ]. Fish species were chosen based on their importance to sport fishing in the state: walleye ( Sander vitreus ; n = 17), bluegill ( Lepomis macrochirus ; n = 14), brown trout ( Salmo trutta ; n = 18), northern pike ( Esox lucius ; n = 23), and lake sturgeon ( Acipenser fulvescens ; n = 31).…”

“…Sampling locations consisted of 43 inland waterbody sites across the state of Wisconsin, with multiple species present at 20 of these sites ( Figure 1 , Table S1 ). Samples were collected by the Wisconsin Department of Natural Resources as part of surveys of fish health across Wisconsin and were made available for this study [ 24 ]. Briefly, fish were captured using a number of methods (fyke netting, boom shocking, stream shocking, and capture via spawning weir), blood samples were collected from the caudal vein using an 18–22 gauge needle and 3–5 mL syringe and transferred to no-additive, red top glass blood tubes.…”

“…We conducted a study of the blood viromes of five species of sport fish across the state of Wisconsin, USA, collected from 2016 to 2020. Sport fishing in Wisconsin holds great cultural and economic significance [ 23 ], and viral diseases have previously impacted wild fish populations in the state, sometimes dramatically [ 18 , 24 ]. We performed a metagenomic survey of apparently healthy fish to (1) examine the total virome composition of these fish, (2) describe the phylogenetic relationships of potentially novel viruses, and (3) investigate whether viral prevalence, richness, or abundance varies between factors such as host species, location, or viral family.…”

Susceptibility of Pallid Sturgeon to viral hemorrhagic septicemia virus genotype IVb

“…Viral hemorrhagic septicemia virus IVb (VHSV‐IVb) isolates were initially found in the Great Lakes region and continue to be detected in the watershed (Bain et al 2010; Thiel et al 2021). Since their first detection in 2005, VHSV‐IVb isolates have demonstrated a broad freshwater species host range, with >30 susceptible freshwater species, including species harvested, cultured, and/or stocked for bait, sport, or food, and are responsible for widespread epidemics (Elsayed et al 2006; Kim and Faisal 2010; Faisal et al 2012; Stepien and Niner 2020).…”