Information for vets about HPAI (bird flu)

Latest information about H5 bird flu

H5 bird flu (H5N1 avian influenza clade 2.3.4.4b) is a notifiable disease. It has caused high numbers of deaths in poultry and wild birds overseas.

The first case of H5 bird flu was confirmed in New Zealand on 15 July 2026.

The Ministry for Primary Industries (MPI) is the lead agency for H5 bird flu and has been working with industry, local councils, as well the Department of Conservation (DOC), the Ministry of Health, and Health New Zealand (Te Whatu Ora) to get ready. Veterinarians have an important role in providing evidence-based advice to clients and communities, as well as reporting any suspected cases of H5 bird flu to MPI.

If you suspect any form of high pathogenicity avian influenza, contact the exotic pest and disease hotline on 0800 809 966 immediately. The hotline is open 24 hours a day, 7 days a week.

Tou can also make an online report at report.mpi.govt.nz

If you use this method, select the ‘dead or dying wild birds’ option from the dropdown list and then the type of bird you have found.

Which animals can be affected by H5 bird flu

H5 bird flu can affect any birds but is more likely to affect colony nesting birds such as red and black-billed gulls, gannets, terns and other seabirds or animals interacting with these birds, due to the close contact transmission of the virus through secretions and droppings.

The virus can establish in migrating wildlife species, which has allowed it to spread across the Atlantic to the Americas and the Antarctic Peninsula, as well as Australasia.

Overseas, infected mammals have included dairy cattle, goats, cats, dogs, and several wildlife species.

Be alert for signs in commercial and domestic poultry, and wildlife

At this stage, wild birds such as seabirds, shorebirds, and waterfowl are groups of concern. High mortality of multiple birds would be a significant indicator. There may be other non-specific signs of disease in infected birds, ranging from respiratory, enteric and neurological disease of varied severity to acute or progressive severe systemic disease with very high mortality.

Include H5 bird flu in your differential diagnosis list for any unusual disease outbreaks or mortality events.

Clinical signs of H5 bird flu

The most obvious sign of H5 bird flu is rapid mortality among a group of birds. The clinical signs of HPAI in birds are extensive and could cover a variety of clinical conditions across all species of birds.

Clinical signs in domestic backyard poultry flocks

Many of the clinical signs of H5 bird flu can also occur with common diseases in domestic poultry and, on their own, are not unusual in individual birds. However, if several birds in the same shed, coop or shared airspace are affected, the following signs may indicate H5 bird flu:

unexpected deaths – sudden and rapid increase in the number of birds found dead with several other birds affected in the same shed or air space
unresponsive – quiet, withdrawn birds that are reluctant to move or interact and may appear fluffed up and easily fatigued
huddling – birds clustering together or against coop equipment, such as nesting boxes or drinkers
bruising – blood spots or swelling, haemorrhages on shanks of the legs and under the skin of the neck
coughing, sneezing, gurgling, rattling or gaping
focal facial swelling, for example, around the eyes
ocular discharge
cessation or marked reduction in egg production
loss of appetite or marked decrease in feed consumption
sudden increase or decrease in water consumption
lethargy and depression
fever or noticeable increase in body temperature
diarrhoea – discoloured or loose, watery droppings.

Clinical signs in wild birds

Overseas, H5 bird flu has been detected in many wild bird species but is most commonly found in waterbirds (such as swans, ducks and geese) and scavenging birds (such as gulls and some birds of prey). Signs of infection can vary greatly between species and individual birds and may affect the respiratory, digestive or nervous system.

For example, swans often show neurological signs such as head shaking, twisting of the neck, or swimming in circles. Birds of prey are more likely to show eye or respiratory problems, while ducks and geese may show few or no obvious signs of illness.

The signs that are observed can also depend on how closely birds are monitored. Seabirds may only be noticed when they are found sick or dead on beaches, whereas birds living near people, such as swans on local ponds, may be observed earlier in the course of illness. In species that normally gather in flocks, affected birds may separate themselves from the group.

Spillover to other species

If H5 bird flu becomes established in wild birds in New Zealand, veterinarians should be alert for spillover into other species.

Spillover events typically occur when animals live in close contact with infected birds or are exposed to infected carcasses or faeces. Overseas, H5 bird flu infections have been reported in a range of mammals, including dairy cattle, goats, cats, dogs, and several wildlife species.

Clinical signs in non-avian species

Clinical signs may not always resemble those commonly associated with influenza. For example, dairy cattle affected during the 2024 outbreak in the United States showed an unusual clinical presentation. Rather than affecting the respiratory tract, the virus mostly targeted the mammary gland, with symptoms such as sudden, drastic drops in milk production, fever, lethargy and producing abnormal (thick, colostrum-like) milk.

Veterinarians should consider H5 bird flu as a possible differential diagnosis when investigating unexplained illness.

How bird flu spreads and how to minimise transmission

H5 bird flu spreads between birds by direct contact with infected birds and through exposure to contaminated body fluids, faeces, feed, water or environments. The virus can also be carried on vehicles, clothing, footwear, and equipment. While H5 bird flu is not an airborne disease, droplets can spread the virus over short distances (less than 10 metres).

Strict biosecurity, good hygiene practices, and appropriate personal protection equipment (PPE) are essential to reduce the risk of disease transmission between birds and to people.

One of the most effective ways to minimise spread is to carefully manage animal movements. Suspect birds should be examined away from other animals, ideally in an isolation facility or a separate area that can be thoroughly cleaned and disinfected afterwards.

When handling birds, avoid touching your face and wash your hands thoroughly after contact with birds or potentially contaminated surfaces. Use appropriate disinfectants for footbaths and environmental cleaning. Phones and other devices used to capture photos or videos should also be cleaned and disinfected before and after use.

Managing suspected H5 bird flu in the clinic

Telephone triage and full consideration of the history and clinical signs, alongside practice-based bird flu risk assessment, can be used to make an appropriate decision whether to see the bird outside or inside the veterinary practice. This may be supported by photos or videos.

For captive birds, collect information about:

where and how the birds are housed
any recent introductions of new birds
the duration of clinical signs
the number of birds affected
any recent contact with wild birds or their environment.

This information can help assess the likelihood of H5 bird flu and guide appropriate biosecurity measures before the bird arrives at the clinic.

Guidance for general practice veterinarians on H5 bird flu [PDF, 2 MB]

Avian influenza health and safety guidance

Health New Zealand | Te Whatu Ora has developed guidance for workplaces where people may come into contact with birds and other animals at risk of avian influenza.

The guidance is designed for occupational groups that may be exposed to: