Validation of a reduction in time for avian influenza virus isolation using specific pathogen-free embryonated chicken eggs.

Background: The international gold standard for avian influenza virus (AIV) diagnosis is virus isolation (VI) in specific pathogen-free embryonated chicken eggs (ECEs). AIV isolation typically involves a 6-day turnaround, during which premises under suspicion for notifiable AIV infection are held under restriction regardless of molecular diagnoses, often with significant welfare implications.

Methods: A reduction in time for negation by VI was investigated following experimental inoculation of AIV from known-positive original clinical material into ECEs.

Infectious bronchitis virus: an overview of the "chicken coronavirus".

Infectious bronchitis virus (IBV) is a highly contagious avian that affects mainly chickens () but can circulate in other avian species. IBV constitutes a significant threat to the poultry industry, causing reduced egg yield, growth and mortality levels that can vary in impact. The virus can be transmitted horizontally by inhalation or direct/indirect contact with infected birds or contaminated fomites, vehicles, farm personnel and litter (Figure 1).

A multi-species, multi-pathogen avian viral disease outbreak event: Investigating potential for virus transmission at the wild bird - poultry interface.

A free-range organic broiler () premises in Staffordshire was infected by high pathogenicity avian influenza virus (HPAIV) H5N8 during the 2020-2021 epizootic in the United Kingdom (UK). Following initial confirmation of the infection in poultry, multiple wild bird species were seen scavenging on chicken carcasses. Detected dead wild birds were subsequently demonstrated to have been infected and succumbed to HPAIV H5N8.

Efficient and Informative Laboratory Testing for Rapid Confirmation of H5N1 (Clade 2.3.4.4) High-Pathogenicity Avian Influenza Outbreaks in the United Kingdom.

During the early stages of the UK 2021-2022 H5N1 high-pathogenicity avian influenza virus (HPAIV) epizootic in commercial poultry, 12 infected premises (IPs) were confirmed by four real-time reverse-transcription-polymerase chain reaction (RRT)-PCRs, which identified the viral subtype and pathotype. An assessment was undertaken to evaluate whether a large sample throughput would challenge laboratory capacity during an exceptionally large epizootic; hence, assay performance across our test portfolio was investigated. Statistical analysis of RRT-PCR swab testing supported it to be focused on a three-test approach, featuring the matrix (M)-gene, H5 HPAIV-specific (H5-HP) and N1 RRT-PCRs, which was successfully assessed at 29 subsequent commercial IPs.

High pathogenicity avian influenza: targeted active surveillance of wild birds to enable early detection of emerging disease threats.

Avian influenza (AI) is an important disease that has significant implications for animal and human health. High pathogenicity AI (HPAI) has emerged in consecutive seasons within the UK to cause the largest outbreaks recorded. Statutory measures to control outbreaks of AI virus (AIV) at poultry farms involve disposal of all birds on infected premises.

Incursion of H5N8 high pathogenicity avian influenza virus (HPAIV) into gamebirds in England.

The 2016-17 European outbreak of H5N8 HPAIV (Clade 2.3.4.

Intranasal Infection of Ferrets with SARS-CoV-2 as a Model for Asymptomatic Human Infection.

Ferrets were experimentally inoculated with SARS-CoV-2 (severe acute respiratory syndrome (SARS)-related coronavirus 2) to assess infection dynamics and host response. During the resulting subclinical infection, viral RNA was monitored between 2 and 21 days post-inoculation (dpi), and reached a peak in the upper respiratory cavity between 4 and 6 dpi. Viral genomic sequence analysis in samples from three animals identified the Y453F nucleotide substitution relative to the inoculum.

Interspecies Transmission of Reassortant Swine Influenza A Virus Containing Genes from Swine Influenza A(H1N1)pdm09 and A(H1N2) Viruses.

Influenza A(H1N1)pdm09 (pH1N1) virus has become established in swine in the United Kingdom and currently co-circulates with previously enzootic swine influenza A virus (IAV) strains, including avian-like H1N1 and human-like H1N2 viruses. During 2010, a swine influenza A reassortant virus, H1N2r, which caused mild clinical disease in pigs in the United Kingdom, was isolated. This reassortant virus has a novel gene constellation, incorporating the internal gene cassette of pH1N1-origin viruses and hemagglutinin and neuraminidase genes of swine IAV H1N2 origin.

Statistical modelling of data showing pandemic H1N1 2009 swine influenza a virus infection kinetics in vaccinated pigs.

A swine influenza A pandemic 2009 H1N1 (pH1N1) virus was used in a pig challenge model to investigate the efficacy of whole inactivated vaccines homologous or heterologous to the challenge virus as well as a commercial vaccine. Nasal shedding of viral RNA was monitored daily by real-time, quantitative RT-PCR (RRT-qPCR) as detailed (1). Here we report the statistical modelling of the viral RNA shedding kinetics.

Comparative micro-epidemiology of pathogenic avian influenza virus outbreaks in a wild bird population.

Understanding the epidemiological dynamics of highly pathogenic avian influenza virus (HPAIV) in wild birds is crucial for guiding effective surveillance and control measures. The spread of H5 HPAIV has been well characterized over large geographical and temporal scales. However, information about the detailed dynamics and demographics of individual outbreaks in wild birds is rare and important epidemiological parameters remain unknown.

Vaccine-mediated protection of pigs against infection with pandemic H1N1 2009 swine influenza A virus requires a close antigenic match between the vaccine antigen and challenge virus.

Swine influenza A virus (SwIV) infection has considerable economic and animal welfare consequences and, because of the zoonotic potential, can also have public health implications. The 2009 pandemic H1N1 'swine-origin' infection is now endemic in both pigs and humans. In Europe, avian-like H1N1, human-like H1N2, human-like swine H3N2 and, since 2009, pandemic H1N1 (pH1N1) lineage viruses and reassortants, constitute the dominant subtypes.

An enzyme-linked immunosorbent assay for detection of avian influenza virus subtypes H5 and H7 antibodies.

Background: Avian influenza virus (AIV) subtypes H5 and H7 attracts particular attention because of the risk of their potential pathogenicity in poultry. The haemagglutination inhibition (HI) test is widely used as subtype specific test for serological diagnostics despite the laborious nature of this method. However, enzyme-linked immunosorbent assays (ELISAs) are being explored as an alternative test method.

Challenges for accurate and prompt molecular diagnosis of clades of highly pathogenic avian influenza H5N1 viruses emerging in Vietnam.

Forty-six chickens and 48 ducks were sampled from four Vietnamese poultry premises in 2009 infected with H5N1 highly pathogenic avian influenza (HPAI) clade 2.3.2 and 2.

Evaluation of lateral flow devices for identification of infected poultry by testing swab and feather specimens during H5N1 highly pathogenic avian influenza outbreaks in Vietnam.

Background: Evaluation of two commercial lateral flow devices (LFDs) for avian influenza (AI) detection in H5N1 highly pathogenic AI infected poultry in Vietnam.

Objectives: Determine sensitivity and specificity of the LFDs relative to a validated highly sensitive H5 RRT PCR.

Methods: Swabs (cloacal and tracheal) and feathers were collected from 46 chickens and 48 ducks (282 clinical specimens) and tested by both LFDs and H5 RRT PCR.

Rapid death of duck cells infected with influenza: a potential mechanism for host resistance to H5N1.

Aquatic birds are the natural reservoir for most subtypes of influenza A, and a source of novel viruses with the potential to cause human pandemics, fatal zoonotic disease or devastating epizootics in poultry. It is well recognised that waterfowl typically show few clinical signs following influenza A infection, in contrast, terrestrial poultry such as chickens may develop severe disease with rapid death following infection with highly pathogenic avian influenza. This study examined the cellular response to influenza infection in primary cells derived from resistant (duck) and susceptible (chicken) avian hosts.

Evaluation of two commercial lateral flow devices (LFDs) used for flockside testing of H5N1 highly-pathogenic avian influenza infections in backyard gallinaceous poultry in Egypt.

Quickvue and Anigen lateral flow devices (LFDs) were evaluated for detection of H5N1 highly pathogenic avian influenza (HPAI) infections in Egyptian poultry. Sixty five chickens and two turkeys were sampled in eight flocks where H5N1 HPAI infection was suspected. Swabs (tracheal and cloacal) and feathers were collected from each bird for flockside testing by the two LFDs.

Real time reverse transcription (RRT)-polymerase chain reaction (PCR) methods for detection of pandemic (H1N1) 2009 influenza virus and European swine influenza A virus infections in pigs.

Background: There is a requirement to detect and differentiate pandemic (H1N1) 2009 (H1N1v) and established swine influenza A viruses (SIVs) by real time reverse transcription (RRT) PCR methods.

Objectives: First, modify an existing matrix (M) gene RRT PCR for sensitive generic detection of H1N1v and other European SIVs. Second, design an H1 RRT PCR to specifically detect H1N1v infections.

Validated RealTime reverse transcriptase PCR methods for the diagnosis and pathotyping of Eurasian H7 avian influenza viruses.

Background: Avian influenza (AI) caused by H7 AI viruses (AIVs) of both low pathogenicity (LP) and high pathogenicity (HP) are notifiable poultry diseases.

Objectives: Design and validate two RealTime reverse transcriptase polymerase chain reactions (RRT PCRs) for Eurasian H7 AIV detection and pathotyping.

Methods: The H7 RRT PCRs amplified within the (i) HA2 and (ii) cleavage site CS regions of the haemagglutinin gene.