Detection of viral hemorrhagic septicemia in round gobies in New York State (USA) waters of Lake Ontario and the St. Lawrence River

Abstract

In May 2006 a large mortality of several thousand round gobies Neogobius melanostomus (Pallas, 1814) occurred in New York waters of the St. Lawrence River and Lake Ontario. Necropsies of sampled fish from these areas showed pallor of the liver and gills, and hemorrhagic areas in many organs. Histopathologic examination of affected tissues revealed areas of necrosis and hemorrhage. Inoculations of fathead minnow Pimephales promelas (Rafinesque, 1820) cell cultures with dilutions of tissue samples from the necropsied gobies produced a cytopathic effect within 5 d postinoculation. Samples of cell culture supernatant were tested using RT-PCR and confirmed the presence of viral hemorrhagic septicemia virus (VHSV). Sequence analysis of the VHSV isolate resulted in its assignment to the type-IVb subgroup. The detection of VHSV in a relatively recent invasive fish species in the Great Lakes and the potential impact of VHSV on the ecology and economy of the area will require further investigation and careful management considerations. KEY WORDS: Viral hemorrhagic septicemia · VHSV · Round goby · New York State Resale or republication not permitted without written consent of the publisherDis Aquat Org 76: [187][188][189][190][191][192] 2007 lege of Veterinary Medicine, Cornell University. The fish arrived at Cornell in moribund or freshly dead condition and were processed for diagnostic evaluation. The second sample consisted of 9 dead round gobies collected on 15 May 2006 from Sandy Creek, Lake Ontario, west of Rochester, New York. These fish were transported on ice to the AAHP at Cornell University.Cape Vincent, St. Lawrence River samples. All moribund fish were euthanized with an overdose of MS-222 (tricaine methanesulfonate, Western Chemical) in water. Eight fish were processed for diagnostic evaluation. The remaining 15 fish were frozen whole at -20°C for future evaluation if necessary. The procedure for diagnostic evaluation is described by Noga (1996) and included collecting skin scrapings and gill clip samples, sterile collection of posterior kidney samples for bacteriology, gross pathology and collection of tissues for histopathology and virology. Samples of liver, kidney, spleen and gonad were collected in 2 pooled samples for detection of viral agents. The first pooled sample (Sample A) included tissues from gobies that were dead at the time of presentation. The second pooled sample (Sample B) included fish that were moribund at the time of presentation. These samples collected for virus isolation were processed as described in the following sections. Attempts at bacterial isolation consisted of cultures taken from the posterior kidneys that were streaked onto blood agar (TSA II 5% SB, BBL™, Becton Dickinson). These cultures were incubated for 7 d at 21°C. Samples of intestines, gut contents and liver were collected to test additionally for type-E botulism by PCR (Getchell et al. 2006).Irondequoit Bay, Lake Ontario samples. Five fish were processed for diagnostic evaluation. Skin scrapings, gill ...

Immunohistochemistry and pathology of multiple Great Lakes fish from mortality events associated with viral hemorrhagic septicemia virus type IVb

“…The most notable gross pathological findings in the initial submission of round gobies have previously been described (Groocock et al 2007). Subsequent round goby submissions to Cornell exhibited similar gross lesions including petechial hemorrhages in the muscle tissue, gonads, and liver.…”

“…The virus was initially found in the Great Lakes, and more specifically in the freshwater drum Aplodinotus grunniens in Lake Ontario, in the spring of 2005 (Lumsden et al 2007); however, it was present in the muskellunge Esox masquinongy in Lake St. Clair, Michigan, USA, since at least 2003 (Elsayed et al 2006). Most recently, VHSV IVb has been detected in the round goby Neogobius melanostomus in the waters of Lake Ontario and the St. Lawrence River in the summer of 2006 (Groocock et al 2007). Since 2005, the total number of species that are affected in the United States has risen to 28 (Winton et al 2008), including several commercially and recreationally important fish such as the walleye Sander vitreus and the yellow perch Perca flavescens.…”

“…Descriptions of VHSV IVb light microscopic lesions in wild fish are not routinely performed, although there are exceptions (Groocock et al 2007, Lumsden et al 2007. Diagnosis of VHSV is more commonly made by molecular techniques as surveys of the Great Lakes and the surrounding watersheds continue.…”

“…The histological changes of freshwater drum (Lumsden et al 2007) and round goby (Groocock et al 2007) collected in 2005 were described previously.…”

Role of Viral Hemorrhagic Septicemia Virus Matrix (M) Protein in Suppressing Host Transcription

“…In 2005, VHSV-IVb was first isolated from muskellunge (Esox masquinongy) from Lake Ontario and subsequently found in an archived sample from Lake St. Clair, Ontario, dating back to 2003 (isolate MI03GL) (27). VHSV-IVb caused massive die-offs among many freshwater species during the next decade and continues to pose a potential threat to both fish farming and the sport fishing industry in the Great Lakes watershed (28)(29)(30). VHSV-IVb has been isolated from at least 31 fish species, including muskellunge, yellow perch, and walleye (28), and has been detected in all five of the Laurentian Great Lakes (31,32).…”