Viral pathogen detection in U.S. game-farm mallard () flags spillover risk to wild birds.

The threat posed by emerging infectious diseases is a major concern for global public health, animal health and food security, and the role of birds in transmission is increasingly under scrutiny. Each year, millions of mass-reared game-farm birds are released into the wild, presenting a unique and a poorly understood risk to wild and susceptible bird populations, and to human health. In particular, the shedding of enteric pathogens through excrement into bodies of water at shared migratory stop-over sites, and breeding and wintering grounds, could facilitate multi-species long-distance pathogen dispersal and infection of high numbers of naive endemic birds annually.

Global dissemination of influenza A virus is driven by wild bird migration through arctic and subarctic zones.

Influenza A viruses (IAV) circulate endemically among many wild aquatic bird populations that seasonally migrate between wintering grounds in southern latitudes to breeding ranges along the perimeter of the circumpolar arctic. Arctic and subarctic zones are hypothesized to serve as ecologic drivers of the intercontinental movement and reassortment of IAVs due to high densities of disparate populations of long distance migratory and native bird species present during breeding seasons. Iceland is a staging ground that connects the East Atlantic and North Atlantic American flyways, providing a unique study system for characterizing viral flow between eastern and western hemispheres.

Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos).

Since 2014, widespread, annual mortality events involving multiple species of seabirds have occurred in the Gulf of Alaska, Bering Sea, and Chukchi Sea. Among these die-offs, emaciation was a common finding with starvation often identified as the cause of death. However, saxitoxin (STX) was detected in many carcasses, indicating exposure of these seabirds to STX in the marine environment.

Highly pathogenic avian influenza virus H5N2 (clade 2.3.4.4) challenge of mallards age appropriate to the 2015 midwestern poultry outbreak.

Background: The 2015 highly pathogenic avian influenza virus (HPAIV) H5N2 clade 2.3.4.

Investigation of Algal Toxins in a Multispecies Seabird Die-Off in the Bering and Chukchi Seas.

Between 2014 and 2017, widespread seabird mortality events were documented annually in the Bering and Chukchi seas, concurrent with dramatic reductions of sea ice, warmer than average ocean temperatures, and rapid shifts in marine ecosystems. Among other changes in the marine environment, harmful algal blooms (HABs) that produce the neurotoxins saxitoxin (STX) and domoic acid (DA) have been identified as a growing concern in this region. Although STX and DA have been documented in Alaska (US) for decades, current projections suggest that the incidence of HABs is likely to increase with climate warming and may pose a threat to marine birds and other wildlife.

Avian influenza virus prevalence in marine birds is dependent on ocean temperatures.

Waterfowl and shorebirds are the primary hosts of influenza A virus (IAV), however, in most surveillance efforts, large populations of birds are not routinely examined; specifically marine ducks and other birds that reside predominately on or near the ocean. We conducted a long-term study sampling sea ducks and gulls in coastal Maine for IAV and found a virus prevalence (1.7%) much lower than is typically found in freshwater duck populations.

The Expectations and Challenges of Wildlife Disease Research in the Era of Genomics: Forecasting with a Horizon Scan-like Exercise.

The outbreak and transmission of disease-causing pathogens are contributing to the unprecedented rate of biodiversity decline. Recent advances in genomics have coalesced into powerful tools to monitor, detect, and reconstruct the role of pathogens impacting wildlife populations. Wildlife researchers are thus uniquely positioned to merge ecological and evolutionary studies with genomic technologies to exploit unprecedented "Big Data" tools in disease research; however, many researchers lack the training and expertise required to use these computationally intensive methodologies.

Aerosol Transmission of Gull-Origin Iceland Subtype H10N7 Influenza A Virus in Ferrets.

Subtype H10 influenza A viruses (IAVs) have been recovered from domestic poultry and various aquatic bird species, and sporadic transmission of these IAVs from avian species to mammals (i.e., human, seal, and mink) are well documented.

Mortality of Little Brown Bats ( Myotis lucifugus carissima) Naturally Exposed to Microcystin-LR.

We describe a die-off of little brown bats ( Myotis lucifugus carissima) associated with acute intoxication with microcystin-LR in 2016 at Scofield Reservoir in Utah, US. High levels of this cyanotoxin in water from the reservoir and gastrointestinal content of bats supported this diagnosis.

Inferring epidemiologic dynamics from viral evolution: 2014-2015 Eurasian/North American highly pathogenic avian influenza viruses exceed transmission threshold, = 1, in wild birds and poultry in North America.

Highly pathogenic avian influenza virus (HPAIV) is a multihost pathogen with lineages that pose health risks for domestic birds, wild birds, and humans. One mechanism of intercontinental HPAIV spread is through wild bird reservoirs, and wild birds were the likely sources of a Eurasian (EA) lineage HPAIV into North America in 2014. The introduction resulted in several reassortment events with North American (NA) lineage low-pathogenic avian influenza viruses and the reassortant EA/NA H5N2 went on to cause one of the largest HPAIV poultry outbreaks in North America.

Grass is not always greener: rodenticide exposure of a threatened species near marijuana growing operations.

Objective: Marijuana (Cannabis spp.) growing operations (MGO) in California have increased substantially since the mid-1990s. One environmental side-effect of MGOs is the extensive use of anticoagulant rodenticides (AR) to prevent damage to marijuana plants caused by wild rodents.

CHLAMYDIA PSITTACI IN FERAL ROSY-FACED LOVEBIRDS ( AGAPORNIS ROSEICOLLIS) AND OTHER BACKYARD BIRDS IN MARICOPA COUNTY, ARIZONA, USA.

In 2013, a mortality event of nonnative, feral Rosy-faced Lovebirds ( Agapornis roseicollis) in residential backyards in Maricopa County, Arizona, US was attributed to infection with Chlamydia psittaci. In June 2014, additional mortality occurred in the same region. Accordingly, in August 2014 we sampled live lovebirds and sympatric bird species visiting backyard bird feeders to determine the prevalence of DNA and the seroprevalence of antibodies to C.

Potential for Waterborne and Invertebrate Transmission of West Nile Virus in the Great Salt Lake, Utah.

In November and December of 2013, a large mortality event involving 15,000 to 20,000 eared grebes () occurred at the Great Salt Lake (GSL), UT. The onset of the outbreak in grebes was followed by a mortality event in >86 bald eagles (). During the die-off, West Nile virus (WNV) was detected by reverse transcription-PCR (RT-PCR) or viral culture in the carcasses of grebes and eagles submitted to the National Wildlife Health Center.

NO EVIDENCE OF INFECTION OR EXPOSURE TO HIGHLY PATHOGENIC AVIAN INFLUENZAS IN PERIDOMESTIC WILDLIFE ON AN AFFECTED POULTRY FACILITY.

We evaluated the potential transmission of avian influenza viruses (AIV) in wildlife species in three settings in association with an outbreak at a poultry facility: 1) small birds and small mammals on a poultry facility that was affected with highly pathogenic AIV (HPAIV) in April 2015; 2) small birds and small mammals on a nearby poultry facility that was unaffected by HPAIV; and 3) small birds, small mammals, and waterfowl in a nearby natural area. We live-captured small birds and small mammals and collected samples from hunter-harvested waterfowl to test for active viral shedding and evidence of exposure (serum antibody) to AIV and the H5N2 HPAIV that affected the poultry facility. We detected no evidence of shedding or specific antibody to AIV in small mammals and small birds 5 mo after depopulation of the poultry.

High Rates of Detection of Clade 2.3.4.4 Highly Pathogenic Avian Influenza H5 Viruses in Wild Birds in the Pacific Northwest During the Winter of 2014-15.

In 2014, clade 2.3.4.

Experimental Challenge of a Peridomestic Avian Species, European Starlings ( Sturnus vulgaris ), with Novel Influenza A H7N9 Virus from China.

In 2013 a novel avian influenza H7N9 virus was isolated from several critically ill patients in China, and infection with this virus has since caused more than 200 human deaths. Live poultry markets are the likely locations of virus exposure to humans. Peridomestic avian species also may play important roles in the transmission and maintenance of H7N9 at live poultry markets.

SUSCEPTIBILITY AND ANTIBODY RESPONSE OF VESPER SPARROWS (POOECETES GRAMINEUS) TO WEST NILE VIRUS: A POTENTIAL AMPLIFICATION HOST IN SAGEBRUSH-GRASSLAND HABITAT.

West Nile virus (WNV) spread to the US western plains states in 2003, when a significant mortality event attributed to WNV occurred in Greater Sage-grouse ( Centrocercus urophasianus ). The role of avian species inhabiting sagebrush in the amplification of WNV in arid and semiarid regions of the North America is unknown. We conducted an experimental WNV challenge study in Vesper Sparrows ( Pooecetes gramineus ), a species common to sagebrush and grassland habitats found throughout much of North America.

Avian Influenza Ecology in North Atlantic Sea Ducks: Not All Ducks Are Created Equal.

Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations.

Surveillance Potential of Non-Native Hawaiian Birds for Detection of West Nile Virus.

West Nile virus (WNV) was first detected in North America in 1999. Alaska and Hawaii (HI) remain the only U.S.

Demographic and Spatiotemporal Patterns of Avian Influenza Infection at the Continental Scale, and in Relation to Annual Life Cycle of a Migratory Host.

Since the spread of highly pathogenic avian influenza (HPAI) H5N1 in the eastern hemisphere, numerous surveillance programs and studies have been undertaken to detect the occurrence, distribution, or spread of avian influenza viruses (AIV) in wild bird populations worldwide. To identify demographic determinants and spatiotemporal patterns of AIV infection in long distance migratory waterfowl in North America, we fitted generalized linear models with binominal distribution to analyze results from 13,574 blue-winged teal (Anas discors, BWTE) sampled in 2007 to 2010 year round during AIV surveillance programs in Canada and the United States. Our analyses revealed that during late summer staging (July-August) and fall migration (September-October), hatch year (HY) birds were more likely to be infected than after hatch year (AHY) birds, however there was no difference between age categories for the remainder of the year (winter, spring migration, and breeding period), likely due to maturing immune systems and newly acquired immunity of HY birds.

Rapidly Expanding Range of Highly Pathogenic Avian Influenza Viruses.

The movement of highly pathogenic avian influenza (H5N8) virus across Eurasia and into North America and the virus' propensity to reassort with co-circulating low pathogenicity viruses raise concerns among poultry producers, wildlife biologists, aviculturists, and public health personnel worldwide. Surveillance, modeling, and experimental research will provide the knowledge required for intelligent policy and management decisions.

Novel H5 Clade 2.3.4.4 Reassortant (H5N1) Virus from a Green-Winged Teal in Washington, USA.

Eurasian (EA)-origin H5N8 clade 2.3.4.

Avian influenza virus ecology in Iceland shorebirds: intercontinental reassortment and movement.

Shorebirds are a primary reservoir of avian influenza viruses (AIV). We conducted surveillance studies in Iceland shorebird populations for 3 years, documenting high serological evidence of AIV exposure in shorebirds, primarily in Ruddy Turnstones (Arenaria interpres; seroprevalence=75%). However, little evidence of virus infection was found in these shorebird populations and only two turnstone AIVs (H2N7; H5N1) were able to be phylogenetically examined.

North Atlantic migratory bird flyways provide routes for intercontinental movement of avian influenza viruses.

Avian influenza virus (AIV) in wild birds has been of increasing interest over the last decade due to the emergence of AIVs that cause significant disease and mortality in both poultry and humans. While research clearly demonstrates that AIVs can move across the Pacific or Atlantic Ocean, there has been no data to support the mechanism of how this occurs. In spring and autumn of 2010 and autumn of 2011 we obtained cloacal swab samples from 1078 waterfowl, gulls, and shorebirds of various species in southwest and west Iceland and tested them for AIV.