RISKS OF THE EMERGING CORONAVIRUS, FATHEAD MINNOW NIDOVIRUS (ORDER: NIDOVIRALES), ON REPRESENTATIVE GREAT LAKES FISH SPECIES By

RISKS OF THE EMERGING CORONAVIRUS, FATHEAD MINNOW NIDOVIRUS (ORDER: NIDOVIRALES), ON REPRESENTATIVE GREAT LAKES FISH SPECIES By Ashley Marie Baird Since the initial isolation of the fathead minnow nidovirus (FHMNV), it has continued to be found in fathead minnows from several Midwestern states including Wisconsin, Minnesota and Illinois (Batts et al, 2012). Additionally, it has also been isolated from more species including hatchery raised muskellunge (chapter 2), golden shiner (McCann, 2012) and creek chub (Warg, personal communication). Previous work determined the muskellunge FHMNV isolate (MUS-WL) to be distinctly different from the index strain (chapter 2) which raised concerns regarding its host range and pathogenicity to muskellunge. Experimental infections via intraperitoneal (IP) injection were performed to screen the susceptibility of representative Great Lakes native cyprinids and piscivores to FHMNV. Any susceptible species were then screened for susceptibility to FHMNV by immersion techniques to mimic more natural modes of infection. Additional studies were performed to assess the pathogenicity of FHMNV to muskellunge specifically, including determination of the intraperitoneal median lethal dose (IP-LD50), and experimental infections by both immersion and ingestion of FHMNV infected fathead minnows. Details of the disease course including viral shedding and tissues targeted were also investigated. Clinical signs of susceptible species included petechial hemorrhages throughout the eyes, fins and skin, gill pallor, and liver pallor. Histopathologic analysis revealed lesions in the kidneys, spleen and liver of infected fish. FHMNV appears to cause major risks to native cyprinids, the baitfish industry, and muskellunge rehabilitation