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To the Editor: During April 2009, cases of acute respiratory disease in humans caused by influenza A pandemic (H1N1) 2009 virus in Mexico were reported (1). By August 21, 2009, [...]

Water birds are considered the reservoir for avian influenza viruses. We examined this assumption by sampling and real-time reverse transcription--PCR testing of 939 Asian land birds of 153 species. Influenza [...]

To the Editor: Knowledge of avian influenza (AI) virus and its host epidemiology and ecology is essential for effective monitoring and mitigation (1). Applicability of global and continental-scale models will [...]

Abstract Background Avian influenza (AI) viruses infect numerous avian species, and low pathogenicity (LP) AI viruses of the H7 subtype are typically reported to produce mild or subclinical infections in both wild aquatic birds and domestic poultry. However relatively little work has been done to compare LPAI viruses from different avian species for their ability to cause disease in domestic poultry under the same conditions. In this study twelve H7 LPAI virus isolates from North America were each evaluated for their comparative pathogenesis in chickens, ducks, and turkeys. Results All 12 isolates were able to infect all three species at a dose of 106 50% egg infectious doses based on seroconversion, although not all animals seroconverted with each isolate-species combination. The severity of disease varied among isolate and species combinations, but there was a consistent trend for clinical disease to be most severe in turkeys where all 12 isolates induced disease, and mortality was observed in turkeys exposed to 9 of the 12 viruses. Turkeys also shed virus by the oral and cloacal routes at significantly higher titers than either ducks or chickens at numerous time points. Only 3 isolates induced observable clinical disease in ducks and only 6 isolates induced disease in chickens, which was generally very mild and did not result in mortality. Full genome sequence was completed for all 12 isolates and some isolates did have features consistent with adaptation to poultry (e.g. NA stalk deletions), however none of these features correlated with disease severity. Conclusions The data suggests that turkeys may be more susceptible to clinical disease from the H7 LPAI viruses included in this study than either chickens or ducks. However the severity of disease and degree of virus shed was not clearly correlated with any isolate or group of isolates, but relied on specific species and isolate combinations.

Abstract Background Avian influenza virus (AIV) infections have caused heavy economic losses to the poultry industry in Pakistan as well as numerous other regions worldwide. The first introduction of H7N3 AIV to Pakistan occurred during 1995, since then H7N3, H9N2 and H5N1 AIVs have each been sporadically isolated. This report evaluates the genetic origin of the H7N3 viruses from Pakistan collected 1995-2004 and how they disseminated within the country. To accomplish this we produced whole genome sequences for 6 H7N3 viruses and data for the HA and NA genes of an additional 7 isolates. All available sequence from H7N3 AIV from Pakistan was included in the analysis. Results Phylogenetic analysis revealed that there were two introductions of H7 into Pakistan and one N3 introduction. Only one of the H7 introductions appears to have become established in poultry in Pakistan, while the other was isolated from two separate outbreaks 6 years apart. The data also shows that reassortment has occurred between H7N3 and H9N2 viruses in the field, likely during co-infection of poultry. Also, with the exception of these few reassortant isolates, all 8 genes in the predominant H7N3 virus lineage have evolved to be phylogenetically distinct. Conclusions Although rigorous control measures have been implemented in commercial poultry in Pakistan, AIV is sporadically transmitted to poultry and among the different poultry industry compartments (broilers, broiler breeders, table egg layers). Since there is one primary H7 lineage which persists and that has reassorted with the H9N2 AIV in poultry, it suggests that there is a reservoir with some link commercial poultry. On a general level, this offers insight into the molecular ecology of AIV in poultry where the virus has persisted despite vaccination and biosecurity. This data also illustrates the importance of sustained surveillance for AIVs in poultry.

Abstract The current pandemic influenza A H1N1 2009 (pH1N1) was first recognized in humans with acute respiratory diseases in April 2009 in Mexico, in swine in Canada in June, 2009 with respiratory disease, and in turkeys in Chile in June 2009 with a severe drop in egg production. Several experimental studies attempted to reproduce the disease in turkeys, but failed to produce respiratory infection in turkeys using standard inoculation routes. We demonstrated that pH1N1 virus can infect the reproductive tract of turkey hens after experimental intrauterine inoculation, causing decreased egg production. This route of exposure is realistic in modern turkey production because turkey hens are handled once a week for intrauterine insemination in order to produce fertile eggs. This understanding of virus exposure provides an improved understanding of the pathogenesis of the disease and can improve poultry husbandry to prevent disease outbreaks.

Abstract Background Since the emergence of H5N1 high pathogenicity (HP) avian influenza virus (AIV) in Asia, numerous efforts worldwide have focused on elucidating the relative roles of wild birds and domestic poultry movement in virus dissemination. In accordance with this a surveillance program for AIV in wild birds was conducted in Mongolia from 2005-2007. An important feature of Mongolia is that there is little domestic poultry production in the country, therefore AIV detection in wild birds would not likely be from spill-over from domestic poultry. Results During 2005-2007 2,139 specimens representing 4,077 individual birds of 45 species were tested for AIV by real time RT-PCR (rRT-PCR) and/or virus isolation. Bird age and health status were recorded. Ninety rRT-PCR AIV positive samples representing 89 individual birds of 19 species including 9 low pathogenicity (LP) AIVs were isolated from 6 species. A Bar-headed goose (Anser indicus), a Whooper swan (Cygnus cygnus) and 2 Ruddy shelducks (Tadorna ferruginea) were positive for H12N3 LP AIV. H16N3 and H13N6 viruses were isolated from Black-headed gulls (Larus ridibundus). A Red-crested pochard (Rhodonessa rufina) and 2 Mongolian gulls (Larus vagae mongolicus) were positive for H3N6 and H16N6 LP AIV, respectively. Full genomes of each virus isolate were sequenced and analyzed phylogenetically and were most closely related to recent European and Asian wild bird lineage AIVs and individual genes loosely grouped by year. Reassortment occurred within and among different years and subtypes. Conclusion Detection and/or isolation of AIV infection in numerous wild bird species, including 2 which have not been previously described as hosts, reinforces the wide host range of AIV within avian species. Reassortment complexity within the genomes indicate the introduction of new AIV strains into wild bird populations annually, however there is enough over-lap of infection for reassortment to occur. Further work is needed to clarify how AIV is maintained in these wild bird reservoirs.

SARS coronavirus injected intratracheally into chickens, turkeys, geese, ducks, and quail, or into the allantoic sac of their embryonating eggs, failed to cause disease or replicate. This finding suggests that [...]

Environmental testing of poultry premises after an outbreak of an infectious disease like avian influenza (AI) or Newcastle disease is essential to promptly verify virus‐free status and subsequently return to normal operations. In an attempt to establish an optimized sampling protocol, a laboratory study simulating an AI virus‐contaminated poultry house with wire layer cages was conducted. Three sample collection devices, pre‐moistened cotton gauze, dry cotton gauze and a foam swab, were evaluated with each of four sample locations within a cage and when sampling all four locations with one device. Virus was detected with quantitative real‐time RT‐PCR utilizing a standard curve of a quantified homologous isolate of AI virus to determine titre equivalents of virus. The pre‐moistened gauze detected the most virus RNA (100% positive, geometric mean titre [GMT): 3.2 log10 50% embryo infectious doses [EID50] equivalents per 25 cm2) in all four sample locations compared to dry gauze (93% positive, GMT: 2.6 EID50 equivalents per 25 cm2) and foam swabs (95% positive, GMT: 2.8 log10 EID50 equivalents per 25 cm2). The highest viral RNA loads were observed from the cage floor, and when the four locations were sampled with the same device. Overall, the pre‐moistened gauze performed the best, and sampling multiple locations within a cage with the same device would likely optimize detection of residual virus. [ABSTRACT FROM AUTHOR]

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The recent introduction of highly pathogenic avian influenza (HPAI) subtype H5N8 virus into Europe and North America poses major risks to poultry industries, zoologic collections, and wildlife populations; thus, this [...]