Environmental transmission of influenza A virus in mallards.

Wild birds are the natural reservoir hosts of influenza A viruses. Highly pathogenic strains of influenza A viruses pose risks to wild birds, poultry, and human health. Thus, understanding how these viruses are transmitted between birds is critical.

Avian influenza A virus susceptibility, infection, transmission, and antibody kinetics in European starlings.

Avian influenza A viruses (IAVs) pose risks to public, agricultural, and wildlife health. Bridge hosts are spillover hosts that share habitat with both maintenance hosts (e.g.

Influenza A virus surveillance, infection and antibody persistence in snow geese (Anser caerulescens).

Some snow geese (Anser caerulescens) migrate between Eurasia and North America and exhibit high seroprevalence for influenza A viruses (IAVs). Hence, these birds might be expected to play a role in intercontinental dispersal of IAVs. Our objective in this manuscript was to characterize basic incidence and infection characteristics for snow geese to assess whether these birds are likely to significantly contribute to circulation of IAVs.

Low viral doses are sufficient to infect cottontail rabbits with avian influenza A virus.

Influenza A viruses (IAVs) have been reported in wild lagomorphs in environments where they share resources with waterfowl. Recent studies have conclusively shown that a North American lagomorph, cottontail rabbits (Sylvilagus sp.), become infected following exposure to IAVs and can shed significant quantities of virus.

Transmission of H6N2 wild bird-origin influenza A virus among multiple bird species in a stacked-cage setting.

Live bird markets are common in certain regions of the U.S. and in other regions of the world.

Surveillance for highly pathogenic H5 avian influenza virus in synanthropic wildlife associated with poultry farms during an acute outbreak.

In November 2014, a Eurasian strain H5N8 highly pathogenic avian influenza virus was detected in poultry in Canada. Introduced viruses were soon detected in the United States and within six months had spread to 21 states with more than 48 million poultry affected. In an effort to study potential mechanisms of spread of the Eurasian H5 virus, the United States Department of Agriculture coordinated several epidemiologic investigations at poultry farms.

Surveillance for Highly Pathogenic Avian Influenza Virus in Wild Birds during Outbreaks in Domestic Poultry, Minnesota, 2015.

In 2015, a major outbreak of highly pathogenic avian influenza virus (HPAIV) infection devastated poultry facilities in Minnesota, USA. To understand the potential role of wild birds, we tested 3,139 waterfowl fecal samples and 104 sick and dead birds during March 9-June 4, 2015. HPAIV was isolated from a Cooper's hawk but not from waterfowl fecal samples.

Susceptibility of rock doves to low-pathogenic avian influenza A viruses.

Following a 2008 outbreak of North American low-pathogenic H5N8 influenza A virus at an upland gamebird farm, we sero-sampled rock doves (pigeons, Columba livia) at the outbreak site and conducted experimental inoculations of wild-caught pigeons using the H5N8 virus and another low-pathogenic virus (H4N6). While 13% of pigeons at the outbreak site were seropositive, none were positive for exposure to H5, and one was positive for N8. Challenged pigeons exhibited low susceptibility and limited viral RNA excretion for both viruses tested, but at least one individual had RNA loads indicative of the potential for viral transmission to other birds.

Evaluation and optimization of a commercial blocking ELISA for detecting antibodies to influenza A virus for research and surveillance of mallards.

The availability of a validated commercial assay is an asset for any wildlife investigation. However, commercial products are often developed for use in livestock and are not optimized for wildlife. Consequently, it is incumbent upon researchers and managers to apply commercial products appropriately to optimize program outcomes.

When fur and feather occur together: interclass transmission of avian influenza A virus from mammals to birds through common resources.

The potential role of wild mammals in avian influenza A virus (IAV) transmission cycles has received some attention in recent years and cases where birds have transmitted IAV to mammals have been documented. However, the contrasting cycle, wherein a mammal could transmit an avian IAV to birds, has been largely overlooked. We experimentally tested the abilities of two mammalian species to transmit avian IAV to mallards (Anas platyrhynchos) in simulated natural environments.

Ecological routes of avian influenza virus transmission to a common mesopredator: an experimental evaluation of alternatives.

Background: Wild raccoons have been shown to be naturally exposed to avian influenza viruses (AIV). However, the mechanisms associated with these natural exposures are not well-understood.

Methodology/principal Findings: We experimentally tested three alternative routes (water, eggs, and scavenged waterfowl carcasses) of AIV transmission that may explain how raccoons in the wild are exposed to AIV.

Shedding of a low pathogenic avian influenza virus in a common synanthropic mammal--the cottontail rabbit.

Background: Cottontails (Sylvilagus spp.) are common mammals throughout much of the U.S.

Extended viral shedding of a low pathogenic avian influenza virus by striped skunks (Mephitis mephitis).

Background: Striped skunks (Mephitis mephitis) are susceptible to infection with some influenza A viruses. However, the viral shedding capability of this peri-domestic mammal and its potential role in influenza A virus ecology are largely undetermined.

Methodology/principal Findings: Striped skunks were experimentally infected with a low pathogenic (LP) H4N6 avian influenza virus (AIV) and monitored for 20 days post infection (DPI).

West Nile virus infection in American Robins: new insights on dose response.

West Nile virus (WNV) is a vector-borne pathogen that was first detected in the United States in 1999. The natural transmission cycle of WNV involves mosquito vectors and avian hosts, which vary in their competency to transmit the virus. American robins are an abundant backyard species in the United States and appear to have an important role in the amplification and dissemination of WNV.

The safety of ONRAB® in select non-target wildlife.

ONRAB(®) is a recombinant human adenovirus type 5 (HAd5) with the rabies glycoprotein gene incorporated into its genome. ONRAB(®) has been used in Canada as an oral rabies vaccine in target wildlife species such as: red fox (Vulpes vulpes), raccoon (Procyon lotor), and striped skunk (Mepthis mephitis). We evaluated the safety of ONRAB(®) in non-target wildlife species likely to contact the vaccine baits during oral rabies vaccine campaigns in the United States.

Humoral immune response to oral rabies vaccination in raccoon kits: problems and implications.

Little is known about the immunogenicity of RABORAL V-RG(®) (V-RG), an oral rabies vaccine, in raccoon kits (Procyon lotor). The objectives of this study were to characterize the immunogenicity of V-RG in young kits and investigate the potential impact of maternal antibodies on response to vaccination of nursing raccoon kits. Raccoon kits (n=30) were vaccinated at either 3 weeks of age, 7 weeks of age, or assigned as contact controls.

Molecular surveillance of low pathogenic avian influenza viruses in wild birds across the United States: inferences from the hemagglutinin gene.

A United States interagency avian influenza surveillance plan was initiated in 2006 for early detection of highly pathogenic avian influenza viruses (HPAIV) in wild birds. The plan included a variety of wild bird sampling strategies including the testing of fecal samples from aquatic areas throughout the United States from April 2006 through December 2007. Although HPAIV was not detected through this surveillance effort we were able to obtain 759 fecal samples that were positive for low pathogenic avian influenza virus (LPAIV).

Low-pathogenic avian influenza viruses in wild house mice.

Background: Avian influenza viruses are known to productively infect a number of mammal species, several of which are commonly found on or near poultry and gamebird farms. While control of rodent species is often used to limit avian influenza virus transmission within and among outbreak sites, few studies have investigated the potential role of these species in outbreak dynamics.

Methodology/principal Findings: We trapped and sampled synanthropic mammals on a gamebird farm in Idaho, USA that had recently experienced a low pathogenic avian influenza outbreak.

Shedding light on avian influenza H4N6 infection in mallards: modes of transmission and implications for surveillance.

Background: Wild mallards (Anas platyrhychos) are considered one of the primary reservoir species for avian influenza viruses (AIV). Because AIV circulating in wild birds pose an indirect threat to agriculture and human health, understanding the ecology of AIV and developing risk assessments and surveillance systems for prevention of disease is critical.

Methodology/principal Findings: In this study, mallards were experimentally infected with an H4N6 subtype of AIV by oral inoculation or contact with an H4N6 contaminated water source.

Monitoring exposure to avian influenza viruses in wild mammals.

1Avian influenza (AI) viruses primarily circulate in wild waterfowl populations and are occasionally transmitted to domestic poultry flocks. However, the possible roles of other wildlife species, such as wild mammals, in AI virus ecology have not been adequately addressed.2Due to their habitat and behaviour, many wild mammals may be capable of transmitting pathogens among wild and domestic populations.

Increased detection of influenza A H16 in the United States.

As a result of an US interagency avian influenza surveillance effort in wild birds, four isolates of influenza A viruses were initially identified as H7 by hemagglutination inhibition (HI) but subsequently identified as H16 through genetic sequence analysis. We report the development of internal primers for amplification and cycle-sequencing of the full-length H16 gene, increased detection of H16 within the US, and possible steric inhibition or cross-reaction between H7 and H16 antigens during the conventional HI assay. The latter could have critical implications for poultry operations if H16 viruses are detected and mistakenly reported as H7 viruses.