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.

Validation of a screening method for the detection of colistin-resistant E. coli containing mcr-1 in feral swine feces.

A method was developed and validated for the detection of colistin-resistant Escherichia coli containing mcr-1 in the feces of feral swine. Following optimization of an enrichment method using EC broth supplemented with colistin (1 μg/mL) and vancomycin (8 μg/mL), aliquots derived from 100 feral swine fecal samples were spiked with of one of five different mcr-1 positive E. coli strains (between 10 and 10 CFU/g), for a total of 1110 samples tested.

Gulls as Sources of Environmental Contamination by Colistin-resistant Bacteria.

In 2015, the mcr-1 gene was discovered in Escherichia coli in domestic swine in China that conferred resistance to colistin, an antibiotic of last resort used in treating multi-drug resistant bacterial infections in humans. Since then, mcr-1 was found in other human and animal populations, including wild gulls. Because gulls could disseminate the mcr-1 gene, we conducted an experiment to assess whether gulls are readily colonized with mcr-1 positive E.

Persistence of maternal antibodies to influenza A virus among captive mallards (Anas platyrhynchos).

Wild waterfowl are maintenance hosts of most influenza A virus (IAV) subtypes and are often the subjects of IAV surveillance and transmission models. While maternal antibodies have been detected in yolks and in nestlings for a variety of wild bird species and pathogens, the persistence of maternal antibodies to IAVs in mallard ducklings (Anas platyrhynchos) has not been previously investigated. Nonetheless, this information is important for a full understanding of IAV transmission dynamics because ducklings protected by maternal antibodies may not be susceptible to infection.

Impact of body condition on influenza A virus infection dynamics in mallards following a secondary exposure.

Migratory waterfowl are often viewed as vehicles for the global spread of influenza A viruses (IAVs), with mallards (Anas platyrhynchos) implicated as particularly important reservoir hosts. The physical demands and energetic costs of migration have been shown to influence birds' body condition; poorer body condition may suppress immune function and affect the course of IAV infection. Our study evaluated the impact of body condition on immune function and viral shedding dynamics in mallards naturally exposed to an H9 IAV, and then secondarily exposed to an H4N6 IAV.

Molecular characterization of Salmonella enterica isolates associated with starling-livestock interactions.

Bird-livestock interactions have been implicated as potential sources for bacteria within concentrated animal feeding operations (CAFO). In this study we characterized XbaI-digested genomic DNA from Salmonella enterica using pulsed-field gel electrophoresis (PFGE). The PFGE analysis was conducted using 182 S.

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).

Freshwater clams as bioconcentrators of avian influenza virus in water.

We report experimental evidence for bioconcentration of a low-pathogenicity avian influenza virus (H6N8) in the tissue of freshwater clams. Our results support the concept that freshwater clams may provide an effective tool for use in the early detection of influenza A viruses in aquatic environments.

Experimental infection of raccoons (Procyon lotor) with West Nile virus.

To characterize the responses of raccoons to West Nile virus (WNV) infection, we subcutaneously exposed them to WNV. Moderately high viremia titers (≤ 10(4.6) plaque forming units [PFU]/mL of serum) were noted in select individuals; however, peak viremia titers were variable and viremia was detectable in some individuals as late as 10 days post-inoculation (DPI).

Antibody responses of raccoons naturally exposed to influenza A virus.

An investigation was performed to describe the responses of naturally acquired antibodies to influenza A virus in raccoons (Procyon lotor) over time. Seven wild raccoons, some of which had been exposed to multiple subtypes of influenza A virus, were held in captivity for 279 days, and serum samples were collected on 10 occasions during this interval. Serum samples from 9 of 10 bleeding occasions were tested using an epitope-blocking enzyme-linked immunosorbent assay for the presence of antibodies to influenza A virus.

Experimental infection of cliff swallows (Petrochelidon pyrrhonota) with varying doses of West Nile virus.

Cliff swallows (Petrochelidon pyrrhonota) were inoculated with differing doses of West Nile virus (WNV) to evaluate their potential role as reservoir hosts in nature. Swallows often nest in large colonies in habitats and months associated with high mosquito abundance and early WNV transmission in North America. Additionally, cliff swallow diet consists of insects, including mosquitoes, leading to an additional potential route of WNV infection.

Evaluation of an epitope-blocking enzyme-linked immunosorbent assay for the detection of antibodies to influenza A virus in domestic and wild avian and mammalian species.

An epitope-blocking enzyme-linked immunosorbent assay (bELISA) was developed for the detection of antibodies to influenza A virus in taxonomically diverse domestic and wild vertebrate species. In contrast to the bELISAs published previously that require reagent production, manipulation by the end-user, or have not been evaluated for use with both mammalian and avian species, this assay is performed using commercially available recombinant nucleoprotein antigen and corresponding nucleoprotein-specific monoclonal antibody and has been shown to work with multiple avian and mammalian species. The efficacy of the bELISA as a serum screening assay was compared to the agar gel immunodiffusion (AGID) assay using 251 serum samples obtained from experimentally infected mallards (Anas platyrhynchos) and raccoons (Procyon lotor).

Influenza infection in wild raccoons.

Raccoons (Procyon lotor) are common, widely distributed animals that frequently come into contact with wild waterfowl, agricultural operations, and humans. Serosurveys showed that raccoons are exposed to avian influenza virus. We found antibodies to a variety of influenza virus subtypes (H10N7, H4N6, H4N2, H3, and H1) with wide geographic variation in seroprevalence.

Serologic evidence of West Nile virus exposure in North American mesopredators.

Sera from 936 mammalian mesopredators (Virginia opossums, gray foxes, striped skunks, hooded skunks, raccoons, a bobcat, and a red fox) were collected during 2003 and 2004 in California, Arizona, Texas, Louisiana, Ohio, and Wyoming and screened for flavivirus-specific antibodies by an epitope-blocking enzyme-linked immunosorbent assay (blocking ELISA). Serum samples positive for antibodies against flaviviruses were screened for West Nile virus (WNV)-specific antibodies by blocking ELISA and selectively confirmed with plaque-reduction neutralization tests. High prevalence rates were observed in raccoons (45.