1,465
Views
23
CrossRef citations to date
0
Altmetric
Scientific Article

A cross-sectional survey of influenza A infection, and management practices in small rural backyard poultry flocks in two regions of New Zealand

, , , , , , , , , & show all
Pages 74-80 | Received 12 Aug 2009, Accepted 12 Feb 2010, Published online: 16 Feb 2011
 

Abstract

AIMS: To obtain baseline data on the management of small non-commercial backyard poultry flocks, in two rural regions of New Zealand, to investigate potential transmission pathways for avian influenza (AI), and to investigate the presence of AI in these flocks.

METHODS: During August–October 2006 a questionnaire was sent to 105 farms in the Bay of Plenty and Wairarapa with poultry flocks comprising fewer than 50 chickens, located near wetlands where AI virus had been detected previously in wild ducks. Information was collected on the number and species of poultry reared, opportunities for interaction between wild birds and poultry, farm biosecurity measures, and health status of poultry. Between September and November 2006, blood and tracheal/cloacal swabs were collected from poultry on a subset of 12 high-risk farms in each location. Influenza A-specific antibodies in sera were assayed using ELISA, and positive sera were further tested for the presence of H5 and H7 subtype-specific antibodies, using haemagglutination inhibition (HI) assay. The presence of influenza A virus in swabs was detected using realtime reverse transcriptase-PCR (RRT-PCR).

RESULTS: Returned questionnaires were received from 54 farms. Overall, 80% had only chickens, 13% chickens and ducks, and 7% had chickens and other galliform species. Nearly all (96%) kept backyard chickens for personal consumption of eggs, with a small proportion (19%) preparing birds for the table. On surveyed farms wild waterfowl were seen on pastures (70%) and/or farm waterways (46%). Waterfowl were recorded as visiting areas where domestic birds were kept on 31% of farms. Bird litter and manure were composted (94%) or buried (6%) on-farm, as were most (82%) dead birds. During the targeted cross-sectional survey of 24 farms clinical disease was not recorded in any poultry flock. Of 309 chicken sera tested, 11 (3.6%) from five farms across both regions tested positive for influenza A antibodies. In contrast, 16/54 (30%) duck sera from three farms in the Wairarapa were positive. Avian influenza H5 and H7 subtype-specific antibodies were excluded in ELISApositive sera using HI testing, and influenza A virus was not detected using RRT-PCR.

CONCLUSIONS: The study confirmed that small backyard poultry flocks located near waterfowl habitats were exposed to non-notifiable low-pathogenic AI viruses. Findings indicate a number of potential risk pathways for the transmission of AI viruses between wild birds and non-commercial poultry, and hence the need for continued surveillance for AI in backyard flocks and wild birds in New Zealand.

Acknowledgements

The authors thank G Flanagan, F Khan, H Barton and F Cox of AgResearch, for excellent technical assistance; Dr RL Sanson of AsureQuality Ltd, for assistance with AgriBase; and Dr J Williman of the Institute of Environmental Science and Research Ltd, for setting up a database of the study. The generous support from all participating farmers, and the financial support from MAF Biosecurity New Zealand, Environmental Science and Research Ltd, and AgResearch Ltd, are greatly appreciated.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.