High Pathogenicity Avian Influenza (HPAI)


3 min read

The risk to NZ dairy cattle What actions can farmers take? Implications for human health What is DairyNZ doing? Helpful information Additional resources

High Pathogenicity Avian Influenza (HPAI) or bird flu has been found in birds in Antarctica and a strain of HPAI has infected dairy cows in the United States. While the risk of HPAI is considered low due to our isolated location, there are actions dairy farmers can take to be better prepared should it arrive in New Zealand.

New Zealand has never had a case of High Pathogenicity Avian Influenza (HPAI) or avian/bird flu.

HPAI and the risk to New Zealand dairy cattle

HPAI is not a cattle disease, but H5N1, a strain of HPAI, has infected dairy cows in the United States. This is the only known transmission to cows worldwide.

Genomics of the virus in dairy cattle in the USA suggest the infection was from a locally contained spillover event where birds infected cattle on one or more farms in Texas. The movement of infected cattle has spread the virus to other states.

If the strain of HPAI recently found in Antarctica was detected in New Zealand, it would not necessarily spill over to dairy cattle.

In the United States, infected cows generally have had mild symptoms, resulting in a period of decreased milk production. The majority of infected cows recover in 2-3 weeks with supportive care. Not all cows in a herd become sick if infected.

Pasteurisation of milk kills H5N1. In the event of a New Zealand outbreak, pasteurised milk would be safe to consume.

There have been no cases to date of HPAI in beef cattle.

HPAI has killed millions of birds worldwide. Should it arrive in New Zealand, the greatest risk will be to our poultry industry and native birdlife.

What actions can farmers take?

We can’t close our borders to infected migratory birds, but we can be better prepared to protect against the virus if it does arrive.

To safeguard against HPAI, dairy farmers need to:

  1. Practice robust on-farm biosecurity to discourage disease from getting in.
  2. Report unusual symptoms immediately to your vet and isolate symptomatic animals.
  3. Continue good biosecurity practices to stop disease spreading from farm to farm.

Be proactive with biosecurity measures including excellent hygiene, cleaning and disinfecting equipment, securing boundaries, keeping NAIT up to date, separating herds and managing new introductions. Complete the biosecurity planner to help manage risks on your farm.

Restrict bird access to livestock feed and water sources: Ensure pest management protocols are current. Keep water and feed troughs clean.

Report groups of three or more unwell or dying birds, marine mammals, or other wildlife. Do not handle them, call the Biosecurity New Zealand Exotic Pest and Disease hotline immediately on 0800 80 99 66.

Monitor animals: Symptoms of H5N1 in dairy cows are decreased milk production, reduced appetite, thickened and discoloured milk, lethargy, fever and/or dehydration. These symptoms can indicate a range of diseases. Isolate cattle with any of these symptoms and call your vet.

Milk safety: Pay special attention to raw milk safety. Raw milk is the highest risk of spreading disease to other cattle. When feeding calves, the lowest risk for the spread of diseases is calf milk replacer. Ensure any milk you sell or purchase is traceable by filling out/checking feed declaration forms.

Implications for human health

Human infection is rare and generally only found in people who have had a lot of contact with infected birds or other infected animals.

In the US, the H5N1 virus has been detected in a small number of dairy farm workers who had been in close contact with infected cattle. Livestock farmers and workers are being advised to avoid unprotected direct physical contact or close exposure with animals and materials that could potentially be infected or confirmed to be infected with the H5N1 virus.

To date, human-to-human transmission has not been reported.

What is DairyNZ doing to prepare for HPAI?

In the event of an incursion, Biosecurity New Zealand will lead the response with support from the Department of Conservation (DOC) and the Ministry of Health (MoH).

DairyNZ is working with the Ministry for Primary Industries (MPI) and industry partners to keep informed on the spread and impact of HPAI, and we will continue to support our dairy farming community as we know more.

Last updated: May 2024

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