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Objective: To compare the effects of infectious bursal disease virus (IBDV) infection of commercial meat chickens at 0 and 16 days old (d.o.) and determine if IBDV vRNA is quantifiable in litter and dust samples. Methods: Ross meat chickens (n = 60) were orally infected or not with IBDV at 0 or 16 d.o. Blood and faecal samples were collected longitudinally to 28 days post infection (dpi) from six chickens and tissues collected weekly from three euthanased chickens. Relative bursal weight was recorded postmortem. IBDV antibody titres in sera were measured using ELISA and VCN was determined in tissues, faeces, litter and dust using qRT‐PCR. Results: Chickens infected at 16 d.o. had earlier and more severe bursal atrophy, earlier and higher IBDV vRNA load in lymphoid organs and an earlier and greater antibody response to infection than those infected at 0 d.o. Faecal shedding of IBDV between 2 and 6 dpi was observed in both groups followed by cessation with the 0 d.o. group and re‐initiation of shedding at 28 dpi. IBDV was readily detected and quantified in litter and dust samples. Conclusions: The presence of significant maternal antibody (MAb) titres in 0 d.o. chickens provided protection against IBDV replication and bursal atrophy at 7 and 14 days post infection. The reduced titres of MAb present at 16 d.o. did not prevent rapid IBDV replication and early marked bursal atrophy. The observed resistance of 0 d.o. chickens is likely to be a combination of MAb inhibition of IBDV and true age resistance of neonatal chicks. Measurement of IBDV in litter and dust may have research or diagnostic application. [ABSTRACT FROM AUTHOR]

We hypothesise that some influenza virus adaptations to poultry may explain why the barrier for human-to-human transmission is not easily overcome once the virus has crossed from wild birds to chickens. Since the cluster of human infections with H5N1 influenza in Hong Kong in 1997, chickens have been recognized as the major source of avian influenza virus infection in humans. Although often severe, these infections have been limited in their subsequent human-to-human transmission, and the feared H5N1 pandemic has not yet occurred. Here we examine virus adaptations selected for during replication in chickens and other gallinaceous poultry. These include altered receptor binding and increased pH of fusion of the haemagglutinin as well as stalk deletions of the neuraminidase protein. This knowledge could aid the delivery of vaccines and increase our ability to prioritize research efforts on those viruses from the diverse array of avian influenza viruses that have greatest human pandemic potential. Also watch the . [ABSTRACT FROM AUTHOR]

Background Currently, Asian lineage highly pathogenic avian influenza (HPAI) H5N1 has become widespread across continents. These viruses are persistently circulating among poultry populations in endemic regions, causing huge economic losses, and raising concerns about an H5N1 pandemic. To control HPAI H5N1, effective vaccines for poultry are urgently needed. Objective In this study, we developed HPAI virus-like particle (VLP) vaccine as a candidate poultry vaccine and evaluated its protective efficacy and possible application for differentiating infected from vaccinated animals (DIVA). Methods Specific pathogen-free chickens received a single injection of HPAI H5N1 VLP vaccine generated using baculovirus expression vector system. Immunogenicity of VLP vaccines was determined using hemagglutination inhibition (HI), neuraminidase inhibition (NI), and ELISA test. Challenge study was performed to evaluate efficacy of VLP vaccines. Results and Conclusions A single immunization with HPAI H5N1 VLP vaccine induced high levels of HI and NI antibodies and protected chickens from a lethal challenge of wild-type HPAI H5N1 virus. Viral excretion from the vaccinated and challenged group was strongly reduced compared with a mock-vaccinated control group. Furthermore, we were able to differentiate VLP-vaccinated chickens from vaccinated and then infected chickens with a commercial ELISA test kit, which offers a promising strategy for the application of DIVA concept. [ABSTRACT FROM AUTHOR]

Objective To develop a chicken bioassay to detect infective viral pathogens in poultry litter and to determine the effects of type of chicken and age of exposure, as well as the effect of simulated litter transportation, on the level of viral infectivity detected. Design A 5 × 2 × 2 factorial design, plus negative controls. Five chicken litters, including two with deliberate contamination (one transported and one not), two chicken types (specific-pathogen-free ( SPF) Leghorns and Cobb broilers) and two ages at initial exposure (days 1 and 8). Two replicates of each treatment combination. Methods The 10 chickens in each of 22 isolators were either exposed (20 isolators) or not (2 isolators) to 8 L of previously used or deliberately contaminated poultry litter in two deep scratch trays. At day 35 post-exposure, sera were assayed for antibodies against chicken anaemia virus ( CAV), infectious bronchitis virus ( IBV), infectious bursal disease virus ( IBDV), Newcastle disease virus ( NDV) and fowl adenovirus ( FAV). Spleen samples were tested for Marek's disease virus ( MDV) using real-time polymerase chain reaction. Results The bioassay detected CAV, IBDV and FAV, but not NDV, IBV or MDV, in chickens exposed to infected litters. Infection in SPF chickens was detected with greater sensitivity than in the broiler chickens. Sensitivity increased with age at exposure in broiler but not SPF chickens. Simulated transportation for 24 h had little effect on pathogen detection. Conclusion A bioassay based on the exposure of day-old SPF chickens to poultry litter and measurement of seroconversion at day 35 post-exposure is a useful semi-quantitative assay for viral infectivity in poultry litter, with overnight transportation of litter having little effect on the level of viral infectivity detected. This bioassay has applications in research on litter treatment protocols. [ABSTRACT FROM AUTHOR]

Background Since 2005, H5N1 avian influenza (AI) has spread from South-East Asia to over 60 different countries, resulting in the direct death or slaughter of over 250,000,000 poultry. Migratory waterfowl have been implicated in this spread and in Australia there have been numerous isolations of low-pathogenicity AI virus from wild waterfowl and shorebirds. The Department of Human Services, Victoria maintains 10 sentinel free-range chicken flocks in the Riverland at locations that are populated by large numbers of waterfowl known to carry a range of strains of AI. Objective This study analysed historical samples collected in 1991–94 and 2003–06 from the library of serum samples for antibodies against AI to assess the potential for transfer of AI virus from wild waterfowl to free-range poultry. Results Of the 2000 serum samples analysed, 17 were positive for antibodies against AI and 87 were suspect, with a clustering of positive and suspect results in the years 1994, 2003 and 2004. There was also a clustering of positive samples at the site of the Barmah flock. Nine sequential sets of sera from individual chickens with at least one positive result were identified. Analysis of these sequential sets showed that infection was acquired on site but that the antibody response to AI infection was short-lived and was no longer detectable at 8 weeks after the positive finding. Conclusion The surveillance of sentinel chickens is a potential avenue for monitoring the circulation of AI viruses and could provide an early warning system for the commercial poultry industries. [ABSTRACT FROM AUTHOR]

The article reports that contact with wild birds was the most likely source of the H7N7 avian influenza in Lancashire, England, based on investigations into an avian influenza outbreak as of August 2015. Topics covered include the case of highly pathogenic avian influenza (HPAI) in Germany. Also mentioned is the jump of the virus from Anseriformes birds into Galliform poultry.

The author discusses the issue concerning the emergence of new strain of avian influenza virus in China. The author notes that the new virus influenza A(H7N9) is difficult to detect in poultry because it causes few signs of disease in birds. The author cites the World Health Organization (WHO) which reported three cases of human infection with the virus on April 1, 2013 and confirmed 24 cases on April 9, 2013.

The article reports that the Biotechnology and Biological Sciences Research Council (BBSRC) has provided 12 million pounds for two projects related to the prevention of foot-and-mouth disease (FMD) and poultry viruses in Great Britain. It notes that BBSRC has aimed to learn more on the molecular biology of FMD virus. It mentions that efforts in poultry virology will be increased by the assistance from BBSRC.