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At least 379 records · Page 21Linked to original sources
USGS2012

Role of bird movements in the epidemiology of West Nile and avian influenza virus

Avian influenza virus (AIV) is influenced by site fidelity and movements of bird hosts. We examined the movement ecology of American crows ( Corvus brachyrhynchos ) as potential hosts for West Nile virus (WNV) and greater white-fronted geese ( Anser albifrons frontalis ) as potential hosts for AIVs. Research was based on radio-telemetry studies conducted in the Central Valley of California, USA. While crows were restricted to a small area of only a few square kilometers, the distribution of the geese encompassed the northern Central Valley. The crows used 1.5 to 3.5 different roosting areas monthly from February through October, revealing lower roost fidelity than the geese that used 1.1 to 1.5 roosting areas each month from November through March. The crows moved a mean distance of 0.11 to 0.49 km/month between their roosting sites and 2.5 to 3.9 km/month between roosting and feeding sites. In contrast, the geese moved 4.2 to 19.3 km/month between roosting areas, and their feeding range varied from 13.2 to 19.0 km/month. Our comparison of the ecological characteristics of bird movements suggests that the limited local movements of crows coupled with frequent turnover of roosts may result in persistence of focal areas for WNV infection. In contrast, widespread areas used by geese will provide regular opportunities for intermixing of AIVs over a much greater geographic area.

California↗
USGS2007

Detection of viral hemorrhagic septicemia virus

Viral hemorrhagic septicemia virus (VHSV) is considered to be one of the most important viral pathogens of finfish and is listed as reportable by many nations and international organizations (Office International des Epizooties 2006). Prior to 1988, VHSV was thought to be limited to Europe (Wolf 1988; Smail 1999). Subsequently, it was shown that the virus is endemic among many marine and anadromous fish species in both the Pacific and Atlantic Oceans (Meyers and Winton 1995; Skall et al. 2005). Genetic analysis reveals that isolates of VHSV can be divided into four genotypes that generally correlate with geographic location with the North American isolates generally falling into VHSV Genotype IV (Snow et al. 2004). In 2005-2006, reports from the Great Lakes region indicated that wild fish had experienced disease or, in some cases, very large die-offs from VHSV (Elsayed et al. 2006, Lumsden et al. 2007). The new strain from the Great Lakes, now identified as VHSV Genotype IVb, appears most closely related to isolates of VHSV from mortalities that occurred during 2000-2004 in rivers and near-shore areas of New Brunswick and Nova Scotia, Canada (Gagne et al. 2007). The type IVb isolate found in the Great Lakes region is the only strain outside of Europe that has been associated with significant mortality in freshwater species.

Fact Sheet↗
USGS2009

Evaluation of the Efficacy of Iodophor Disinfection of Walleye and Northern Pike Eggs to Eliminate Viral Hemorrhagic Septicemia Virus

Viral hemorrhagic septicemia virus (VHSv) is a serious fish pathogen that has been responsible for large-scale fish kills in the Great Lakes since 2005. It causes high mortality and resulting outbreaks have severe economic consequences for aquaculture. Iodophor disinfection of salmonid eggs is a standard hatchery practice to reduce the risk of pathogen transfer during gamete collection ('spawning') operations and is thus a leading candidate for reducing VHSv transmission during and after spawning of nonsalmonid fishes. However, before it is incorporated by hatcheries during nonsalmonid fish spawning efforts, its safety and effectiveness needs to be evaluated. The USGS Fact Sheet 2009-3107, 'Evaluation of the Efficacy of Iodophor Disinfection of Walleye and Northern Pike Eggs to Eliminate Viral Hemorrhagic Septicemia Virus' presents the results of a study to assess the effectiveness of iodophor disinfection for eliminating VHSv (strain IVb) from fertilized eggs of walleye and northern pike intentionally challenged with VHSv following egg fertilization. Walleye and northern pike egg survival (hatch) following iodophor egg disinfection also was assessed.

Fact Sheet↗
USGS2018

A method for determining avian influenza virus hemagglutinin and neuraminidase subtype association

Methods for grouping specific avian influenza virus (AIV) hemagglutinin (HA) and neuraminidase (NA) subtype reverse-transcription polymerase chain reaction (RT-PCR) products into HA:NA subtypes when egg incubation is technically not feasible were evaluated. These approaches were adopted for use as post hoc methods after melt curve analysis. The methods are based on ratios obtained from amplicon copy count and amplicon molarity and were founded on the premise that infectious particles contain an equal copy count of single-stranded ribonucleic acid segments that encode HA or NA, and thus subtype-specific amplicons from a single AIV isolate should yield a theoretical HA:NA ratio of 1. Single and mixed HA:NA AIV subtype samples were evaluated to determine whether the calculated HA:NA ratios would approach the theoretical value. With these samples, preference was given to the molarity methods to better define and correct for the effects of multiple potential amplicons in the amplification mix. Further, the molarity method was used to evaluate pond sediment spiked with intact virus of known HA:NA subtype to determine whether the method is sufficiently robust to be used with complex samples, such as those acquired from waterfowl habitat. This was a proof-of-concept study intended to guide future methods development. The methods here are not meant to be applied in any other context. From the analysis of fully characterized isolates of North American AIV, the HA:NA molarity-based ratios were found to be 1.63 ± 0.75 (mean ± standard deviation) when corrected for the difference in amplification strength and the production of multiple amplicons in some reactions using equations developed in this study. Copy count HA:NA ratios, obtained from HA and NA subtype (RT-qPCR), were 1.146 ± 0.124 (mean ± standard deviation) when corrected for amplification efficiency. Correct associations of HA:NA subtype sample composition were made with mixed samples containing 1 HA and 2 NA, and 2 HA and 2 NA. When spiked pond sediment was evaluated, the molar ratio obtained for the H4 and N6 identified in the sample was 1.28 with correction and 1.14 without correction.

Open-File Report↗
USGS2008

Influenza A virus infections in land birds, People's Republic of China

Water birds are considered the reservoir for avian influenza viruses. We examined this assumption by sampling and real-time reverse transcription-PCR testing of 939 Asian land birds of 153 species. Influenza A infection was found, particularly among migratory species. Surveillance programs for monitoring spread of these viruses need to be redesigned.

Emerging Infectious Diseases↗
USGS2015

Serologic evidence of influenza A (H14) virus introduction into North America

Although a diverse population of influenza A viruses (IAVs) is maintained among ducks, geese, shorebirds, and gulls, not all of the 16 avian hemagglutinin (HA) subtypes are equally represented (1). The 14th HA subtype, commonly known as the H14 subtype, was historically limited to isolates from the former Soviet Union in the 1980s (2) and was not subsequently detected until 2010, when isolated in Wisconsin, USA from long-tailed ducks and a white-winged scoter (3–5). In the United States, the H14 subtype has since been isolated in California (6), Mississippi, and Texas (7); and has been reported in waterfowl in Guatemala (7). In this study, we examined whether there was serologic evidence of H14 spread among ducks in North America before (2006–2010) and after (2011–2014) the initial detection of the H14 subtype virus on this continent.

Emerging Infectious Diseases↗
USGS2017

Reassortment of influenza A viruses in wild birds in Alaska before H5 Clade 2.3.4.4 Outbreaks

Sampling of mallards in Alaska during September 2014–April 2015 identified low pathogenic avian influenza A virus (subtypes H5N2 and H1N1) that shared ancestry with highly pathogenic reassortant H5N2 and H5N1 viruses. Molecular dating indicated reassortment soon after interhemispheric movement of H5N8 clade 2.3.4.4, suggesting genetic exchange in Alaska or surrounds before outbreaks.

Emerging Infectious Diseases↗
USGS2018

Introduction of Eurasian-origin H8N4 influenza A virus into North America via migratory birds

We identified a Eurasian-origin influenza A(H8N4) virus in North America by sampling wild birds in western Alaska, USA. Evidence for repeated introductions of influenza A viruses into North America by migratory birds suggests that intercontinental dispersal might not be exceedingly rare and that our understanding of viral establishment is incomplete.

Emerging Infectious Diseases↗
USGS2025

Exposure of wild mammals inhabiting Alaska to influenza A(H5N1) virus

Serum samples from wild mammals inhabiting Alaska, USA, showed that 4 species, including Ursus arctos bears and Vulpes vulpes foxes, were exposed to influenza A(H5N1) viruses. Results indicated some mammals in Alaska survived H5N1 virus infection. Surveillance efforts may be improved by incorporating information on susceptibility and detectable immune responses among wild mammals.

Alaska↗
USGS1988

Neutralizing monoclonal antibodies recognize antigenic variants among isolates of infectious hematopoietic necrosis virus

eutralizing monoclonal antibodies were developed against strains of infectious hematopoietic necrosis virus (IHNV) from steelhead trout Salmo gairdneri in the Deschutes River of Oregon, chinook salmon Oncorhynchus tshawytscha in the Sacramento River of California, and rainbow trout Salmo gairdneri reared in the Hagerman Valley of Idaho, USA. These antibodies were tested for neutralization of 12 IHNV isolates obtained from salmonids in Japan, Alaska, Washington, Oregon, California, and Idaho. The antibodies recognized antigenic variants among the isolates and could be used to separate the viruses into 4 groups. The members of each group tended to be related by geographic area rather than by source host species, virulence, or date of isolation.

Diseases of Aquatic Organisms↗
USGS1990

Polymerase chain reaction (PCR) amplification of a nucleoprotein gene sequence of infectious hematopoietic necrosis virus

The polymerase chain reaction [PCR) was used to amplify a portion of the nucleoprotein [NI gene of infectious hematopoietic necrosis virus (IHNV). Using a published sequence for the Round Butte isolate of IHNV, a pair of PCR pnmers was synthesized that spanned a 252 nucleotide region of the N gene from residue 319 to residue 570 of the open reading frame. This region included a 30 nucleotide target sequence for a synthetic oligonucleotide probe developed for detection of IHNV N gene messenger RNA. After 25 cycles of amplification of either messenger or genomic RNA, the PCR product (DNA) of the expected size was easily visible on agarose gels stained with ethidium bromide. The specificity of the amplified DNA was confirmed by Southern and dot-blot analysis using the biotinylated oligonucleotide probe. The PCR was able to amplify the N gene sequence of purified genomic RNA from isolates of IHNV representing 5 different electropherotypes. Using the IHNV primer set, no PCR product was obtained from viral hemorrhagic septicemia virus RNA, but 2 higher molecular weight products were synthesized from hirame rhabdovirus RNA that did not hybridize with the biotinylated probe. The PCR could be efficiently performed with all IHNV genomic RNA template concentrations tested (1 ng to 1 pg). The lowest level of sensitivity was not determined. The PCR was used to amplify RNA extracted from infected cell cultures and selected tissues of Infected rainbow trout. The combination of PCR and nucleic acid probe promises to provide a detection method for IHNV that is rapid, h~ghly specific, and sensitive.

Diseases of Aquatic Organisms↗
USGS1994

Characterization of the glycoprotein of infectious hematopoietic necrosis virus using neutralizing monoclonal antibodies

To study the antigenic nature of the glycoprotein (G protein) of infectious hematopoietic necrosis virus (IHNV), 31 neutralizing monoclonal antibodies (MAbs) were produced against a reference isolate of the virus. The MAbs were compared using a neutralization assay, an enzyme-linked immunosorbent assay (ELISA), and by immunoblotting of the G protein in the native, reduced, and deglycosylated forms. Hybridoma culture fluids of the various MAbs could be diluted from 1:2 to 1:512 and still completely neutralize 1 X 104 plaque-forming units of IHNV. Similarly, the end point dilutions that produced optical density readings of 0.1 or greater in the ELISA were 1:40 to 1:10240. Western blotting showed that all of the MAbs reacted with the G protein in the unreduced (i.e. native) conformation; however, only 9 nine of the MAbs were able to react with the G protein following reduction by 2-mercaptoethanol. Deglycosylation of the protein did not influence the binding ability of any of the MAbs. These data indicate that all the MAbs recognized amino acid sequences on the protein itself and that the IHNV glycoprotein contains linear as well as conformation-dependent neutralizing epitopes. When rainbow trout Oncorhynchus mykiss fingerlings were passively immunized with MAbs against either a linear or a conformation-dependent epitope, the fish were protected against challenge with wild-type IHNV.

Diseases of Aquatic Organisms↗
USGS1994

Association of viral hemorrhagic septicemia virus with epizootic hemorrhages of the skin in Pacific herring Clupea harengus pallasi from Prince William Sound and Kodiak Island, Alaska, USA

Only one-third of the Pacific hernng Clupea harengus pallasi expected to spawn in Prince William Sound (PWS), Alaska, USA, in sprlng 1993 were observed. Of these herring, 15 to 43 '% had external ulcers or subdermal hemorrhages of the skln and fins. A rhabdovirus identified as the North American strain of viral hemorrhagic septicemia virus (VHSV) was isolated from affected herring and 1 Pacific cod Gadus macrocephalus with skin lesions from PWS, and from herring with similar lesions collected near Kodiak Island. No other pathogens were detected in the herring examined. Although VHSV may have been responsible for the skin lesions, there was no confirmed mass herring mortality observed in PWS; hence the actual cause of the reduced herring numbers is still unknown. The same strain of VHSV was subsequently isolated from captive juvenile herring collected from Auke Bay, Alaska, near Juneau, from herring in British Columbia, Canada, and from Puget Sound, Washington, USA. These findings suggest the virus is an opportunistic pathogen that is widely indigenous to Pacific herring populations in the Pacific Northwest and that herring are a significant marine reservoir for North American VHSV.

Alaska↗
USGS2011

Emergence of viral hemorrhagic septicemia virus in the North American Great Lakes region is associated with low viral genetic diversity

Viral hemorrhagic septicemia virus (VHSV) is a fish rhabdovirus that causes disease in a broad range of marine and freshwater hosts. The known geographic range includes the Northern Atlantic and Pacific Oceans, and recently it has invaded the Great Lakes region of North Ame­rica. The goal of this work was to characterize genetic diversity of Great Lakes VHSV isolates at the early stage of this viral emergence by comparing a partial glycoprotein (G) gene sequence (669 nt) of 108 isolates collected from 2003 to 2009 from 31 species and at 37 sites. Phylogenetic analysis showed that all isolates fell into sub-lineage IVb within the major VHSV genetic group IV. Among these 108 isolates, genetic diversity was low, with a maximum of 1.05% within the 669 nt region. There were 11 unique sequences, designated vcG001 to vcG011. Two dominant sequence types, vcG001 and vcG002, accounted for 90% (97 of 108) of the isolates. The vcG001 isolates were most widespread. We saw no apparent association of sequence type with host or year of isolation, but we did note a spatial pattern, in which vcG002 isolates were more prevalent in the easternmost sub-regions, including inland New York state and the St. Lawrence Seaway. Different sequence types were found among isolates from single disease outbreaks, and mixtures of types were evident within 2 isolates from ­individual fish. Overall, the genetic diversity of VHSV in the Great Lakes region was found to be extremely low, consistent with an introduction of a new virus into a geographic region with ­previously naïve host populations.

Diseases of Aquatic Organisms↗
USGS2017

Complete sequences of 4 viral hemorrhagic septicemia virus IVb isolates and their virulence in northern pike fry

Four viral hemorrhagic septicemia virus (VHSV) genotype IVb isolates were sequenced, their genetic variation explored, and comparative virulence assayed with experimental infections of northern pike Esox lucius fry. In addition to the type strain MI03, the complete 11183 bp genome of the first round goby Neogobius melanostomus isolate from the St. Lawrence River, and the 2013 and 2014 isolates from gizzard shad Dorosoma cepedianum die-offs in Irondequoit Bay, Lake Ontario and Dunkirk Harbor, Lake Erie were all deep sequenced on an Illumina platform. Mutations documented in the 11 yr since the MI03 index case from Lake St. Clair muskellunge Esox masquinongy showed 87 polymorphisms among the 4 isolates. Twenty-six mutations were non-synonymous and located at 18 different positions within the matrix protein, glycoprotein, non-virion protein, and RNA polymerase genes. The same 4 isolates were used to infect northern pike fry by a single 1 h bath exposure. Cumulative percent mortality varied from 42.5 to 62.5%. VHSV was detected in 57% (41/72) of the survivors at the end of the 21-d trial, suggesting that the virus was not rapidly cleared. Lesions were observed in many of the moribund and dead northern pike, such as hemorrhaging in the skin and fins, as well as hydrocephalus. Mean viral load measured from the trunk and visceral tissues of MI03-infected pike was significantly higher than the quantities detected in fish infected with the most recent isolates of genotype IVb, but there were no differences in cumulative mortality observed.

Diseases of Aquatic Organisms↗
USGS1999

Evaluation of the protective immunogencity of the N, P, M, NV and G proteins of infectious hematopoietic necrosis virus in rainbow trout Oncorhynchus mykiss using DNA vaccines

The protective immunogenicity of the nucleoprotein (N), phosphoprotein (P), matrix protein (M), non-virion protein (NV) and glycoprotein (G) of the rhabdovirus infectious hematopoietic necrosis virus (IHNV) was assessed in rainbow trout using DNA vaccine technology. DNA vaccines were produced by amplifying and cloning the viral genes in the plasmid pCDNA 3.1. The protective immunity elicited by each vaccine was evaluated through survival of immunized fry after challenge with live virus. Neutralizing antibody titers were also determined in vaccinated rainbow trout Oncorhynchus mykiss fry (mean weight 2 g) and 150 g sockeye salmon Oncorhynchus nerka . The serum from the 150 g fish was also used in passive immunization studies with naïve fry. Our results showed that neither the internal structural proteins (N, P and M) nor the NV protein of IHNV induced protective immunity in fry or neutralizing antibodies in fry and 150 g fish when expressed by a DNA vaccine construct. The G protein, however, did confer significant protection in fry up to 80 d post-immunization and induced protective neutralizing antibodies. We are currently investigating the role of different arms of the fish immune system that contribute to the high level of protection against IHNV seen in vaccinated fish.

Diseases of Aquatic Organisms↗
USGS2005

Efficacy of an infectious hematopoietic necrosis (IHN) virus DNA vaccine in Chinook Oncorhynchus tshawytscha and sockeye O. nerka salmon

The level of protective immunity was determined for Chinook Oncorhynchus tshawytscha and sockeye/kokanee salmon (anadromous and landlocked) O. nerka following intramuscular vaccination with a DNA vaccine against the aquatic rhabdovirus, infectious hematopoietic necrosis virus (IHNV). A DNA vaccine containing the glycoprotein gene of IHNV protected Chinook and sockeye/kokanee salmon against waterborne or injection challenge with IHNV, and relative percent survival (RPS) values of 23 to 86% were obtained under a variety of lethal challenge conditions. Although this is significant protection, it is less than RPS values obtained in previous studies with rainbow trout (O. mykiss). In addition to the variability in the severity of the challenge and inherent host susceptibility differences, it appears that use of a cross-genogroup challenge virus strain may lead to reduced efficacy of the DNA vaccine. Neutralizing antibody titers were detected in both Chinook and sockeye that had been vaccinated with 1.0 and 0.1 ??g doses of the DNA vaccine, and vaccinated fish responded to viral challenges with higher antibody titers than mock-vaccinated control fish. ?? Inter-Research 2005.

Diseases of Aquatic Organisms↗