Avian influenza surveillance expands

Avian influenza (AI) viruses are found in bird populations worldwide. They naturally infect wild water birds (often with no associated sign of disease), but can also affect poultry (such as chickens, ducks and geese) and other birds and mammals – including humans.

AI viruses are classified in terms of their ability to cause disease in chickens. Those with the potential to cause serious disease in both birds and humans are referred to as notifiable avian influenza (NAI) viruses. NAI viruses are monitored by a global network for surveillance and response, which involves national and international animal and human health agencies. New Zealand is a committed participant in the network.

Notifiable avian influenza never detected

New Zealand has developed and maintained an excellent animal disease reporting and investigation system for over 30 years, and has never detected an occurrence of NAI. In 2006, because of ongoing international concern about human and animal health in relation to AI viruses – and with the introduction of broader requirements for reporting to trading partners on the presence of AI viruses – MAF Biosecurity New Zealand (MAFBNZ) commenced a targeted surveillance programme in the commercial poultry industry to provide further evidence that New Zealand is free of NAI.

To date, targeted surveys have been carried out in broiler (meat) chickens, indoor layer (egg) chickens, farms where young layer chickens are raised, and free-range layer chickens. No NAI was found. Surveys are underway on turkey farms, and surveys in other avian industries (for example, ducks) are being planned.

The surveys involve taking blood samples from birds on randomly selected farms throughout New Zealand, and testing them for evidence of NAI. A predetermined number of birds were randomly selected from each shed or flock. Random selection ensures that no accidental bias has been introduced into the results, and helps ensure the results are scientifically valid.

Wild birds also tested

In addition to New Zealand’s general reporting system and targeted surveillance in commercial poultry, ongoing wild bird testing for AI viruses has been performed since 1975. Although migratory wild birds are a route for the introduction of AI viruses into a country, New Zealand is at low risk. This is because New Zealand has no migratory ducks and geese, the birds most likely to act as carriers of AI viruses.

Testing is carried out on New Zealand resident wild birds (e.g., ducks and wrybills) and migratory birds such as godwits, red knots and ruddy turnstones. Sampling involves taking cloacal swabs. MAFBNZ also regularly tests dead birds, reported by members of the public, for a range of exotic diseases including AI.

Low pathogenic viruses

Wild bird surveillance testing has identified 35 different AI viruses in New Zealand during the last 15 years. All of these have been low pathogenic avian influenza viruses, not associated with disease in wild birds.

None of the 35 viruses detected was notifiable avian influenza.

If you suspect that your birds may be infected with AI, please contact your animal health adviser or the MAF Emergency Pest and Disease Hotline on 0800 80 99 66.

  • Biosecurity New Zealand thanks the Poultry Industry Association of New Zealand and the Egg Producers Federation of New Zealand for their cooperation and assistance with avian influenza surveillance programmes.

For further information on notifiable avian influenza:

Wrybills being captured

Wrybills being captured in the Firth of Thames during a pilot study for the wild bird surveillance programme for avian influenza. Photo: Simon Fordham, NaturePix

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Page last updated: 30 April 2008