Bird Flu Explained: From Bird Symptoms to Food Safety, All You Need to Know

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In the last few years, a tidal wave of virulent strains of Avian Influenza (AI) has been building all over the globe, swamping commercially farmed birds with infection. It has killed upwards of half a billion (with a B!) birds so far. For years, our birds were some of the rarest in the world, being free of these infections. The physical isolation of our small island nation protected Kiwi chickens from disease exposure.

But no longer. On the 2nd of December 2024, a strain of highly pathogenic avian influenza was confirmed in New Zealand at an egg production facility in the South Island. Read below for the details of how did the Government choose to kill around 200,000 infected and exposed chickens.

New Zealanders have a lot to learn about bird flu. What is it? Who can catch it and how does it spread? How dangerous is it to animals and people? Are chicken meat and eggs safe to eat? What happens to our farmed chickens? And what about our wild birds?

What is bird flu? 

Cases of Avian Influenza have been recorded as far back as 1878, when it was often originally referred to as ‘fowl plague’. Since then, it has been simmering away, travelling the globe in seasonal ebbs and flows and continuing to mutate into new subtypes. Cases of Avian Influenza have been recorded as far back as 1878, when it was often originally referred to as ‘fowl plague’. Since then, it has been simmering away, travelling the globe in seasonal ebbs and flows and continuing to mutate into new subtypes.

The two most currently well-known strains of bird flu are H5N1 and H7N9, often shortened to H5 and H7. H5N1 was detected in Hong Kong in 1997, while H7N9 was first identified in China in 2013.

New Zealand’s first case of HPIA bird flu was the H7N6 strain.

What are the main strains of bird flu?

Avian Influenza (AI) type A viruses are separated into subtypes based on the two proteins on the surface of the virus, hemagglutinin (HA), or neuraminidase (NA). Many combinations, strains and mutations, of HA and NA proteins are possible.

The different strains of Avian Influenza A viruses are further separated into either low pathogenic (LPAI) – meaning they cause either no illness, or minimal illness – or are highly pathogenic (HPAI) – which cause more serious, severe illness. In New Zealand, various LPAI viruses have been detected in wild birds, as monitored by Biosecurity New Zealand through around 2,000 samples from wild birds each year. December of 2024 was the first time New Zealand detected a case of an HPAI strain, the first being H7N6.

How did Bird Flu get here?

According to the Ministry for Primary Industries, the H7N6 strain of bird flu New Zealand is currently facing at an egg farm in Otago egg “is likely to have developed from interactions with local waterfowl and wild birds”. In certain conditions, low pathogenic viruses have the potential to mutate into highly pathogenic avian influenza.

A likely route for bird flu, HPIA or additional strains of LPIA, to arrive into New Zealand is from wild birds carrying the infection. Given that H5N1 has spread down the length of South America, into the South Georgia islands and onto the Antarctic mainland and surrounding islands, New Zealand is within range for certain birds whose migratory patterns bring them on a non-stop route here. While New Zealand has very tight biosecurity on imports, naturally, wild birds bypass import trade screening protocols and this is why they are considered a likely spreader. It’s a chink in our armour that we cannot practically manage, only monitor.

How do wild birds spread bird flu?

Wild birds can pass infection to commercially farmed birds through getting into feed or water, dropping faeces or feathers and even by contaminating dust and dirt. This is especially problematic for DIY ‘backyard’ chicken keepers, and for farms with free ranging facilities. This means that infected wild birds flying overhead farms or lifestyle blocks can drop faeces into the outdoor range, or when perching on roofs. Or they can contaminate feed and water supplies for the commercial flocks in ranges which aren’t thoroughly netted or enclosed overhead.

Unfortunately, this exposure hazard is often managed in overseas markets by further intensifying the farming practises for the birds: locking them all inside without free ranging, outdoor or open air access.

Why are factory farmed chickens highly susceptible to bird flu?

It is deeply ironic given the bind we are very likely about to be is of our own making. Collective greed with intense factory farming over the last half century has created the conditions for a sharp rise in avian influenza. The insatiable desire to create cheap meat, raising more animals faster and bigger in abhorrent, unhealthy factory farm conditions, has engineered the perfect petri dish of disease. A rise in zoonotic infection (diseases that have jumped from animals to humans) and antibiotic resistance corresponds with our ever-increasing reliance on factory farming animals.

“CAFO” – or “Concentrated Animal Feeding Operation” is a popular term overseas to describe exactly the sort of factory farming that sets the stage for zoonotic disease. Animals are bred as fast and young as possible, then kept in living conditions that are designed for only some to survive, and certainly none to thrive. In many cases, poor, unhealthy genetics set animals up to fail, where they are bred to be big, not to be well. 

These factory farmed chickens and pigs then live short, miserable lives where they are cramped, packed in by the thousands or tens of thousands, sometimes in a cage, and then given industrialised feed designed to fatten them up as fast as possible. All while not allowing for many, or indeed any in some cases, natural animal behaviours. Things like natural light are either absent or limited, access to outdoors is mostly non-existent or highly limited, as are behavioural enrichments. The floor litter becomes rancid with waste with high levels of ammonia in the air. The constant noise of living with thousands of others is inescapable. Such intensive conditions are highly stressful for the animals, which creates a toxic cocktail; bad genetics, unhygienic conditions, standardised bland food, no exercise and high stress are the perfect conditions for infection taking hold and spreading exponentially.

Now that we’re facing the consequences of a problem we engineered, one of the management tactics is to further intensify how we are factory farming animals, in an attempt to protect them from exposure to a problem born out of factory farming in the first place. The merry go round just spins faster!

How does New Zealand manage infection outbreak? 

Months before the arrival of bird flu into the country, Government briefing papers and a response to an Official Information Act request by Animals Aotearoa revealed the short-term plan is known as the ‘three D’s’; “depopulate, dispose, disinfect”. Practically speaking, how will our nation conduct such a mass killing of potentially hundreds of thousands, or even millions, of farmed birds?

Government and poultry industry reps have travelled to comparable production markets in both Australia and the UK in recent months to seek advice on what to do when our farmed birds are infected. Investigating the details of how they might carry out the collective death sentence reads like a macabre menu of horrors. A response to an Official Information Act request about the Government’s plans for disease management has many redacted (hidden) sections. It seems they’d rather keep such unpalatable discussions away from the ears of caring Kiwis.

“Humane depopulation” is the sanitised term for such a mass killing. But in practice, it’s an oxymoron of the highest order. When it comes to exterminating huge numbers of sentient beings, either efficient lethality is the primary goal, or doing so in a more humane way, where softening the experience of the victims, is prioritised. It can’t be both. Sadly, the repeated result overseas sees countries choose killing methods that are cheaper and simpler to execute. ‘Better’ by perhaps every metric, except when considering actual animal welfare.

What ‘depopulation’ methods exist?

There’s a plethora of ways to commit a mass killing of farmed animals at an infected site where handling the animals is undesirable. The whole situation is highly regrettable, as all methods cause suffering and distress, but there is a scale of horror to be addressed. Some ways are notably crueler than others.

Ventilation Shutdown

‘Ventilation Shutdown’ is perhaps the most feral of depopulation methods.

The clue is in the name. All ventilation systems that control airflow and appropriate temperature are deliberately shut off, with the option to also pump heat, carbon dioxide or another gas, into the sealed-off shed, to effectively cook the chooks alive. It’s the ‘dog-in-a-hot-car’ approach but scaled up to create a giant oven where, over several hours, the birds panic in the soaring temperature, inducing deadly heat stroke in 30,000+ chickens at a time. 

Ventilation Shutdown is widely decried by many organisations the world over, including coalitions of veterinarians and welfare experts. However despite the opposition and in many classes formal classification as “not recommended” or “not approved”, it is still a measure that has been used in various developed markets since at least 2006. And not infrequently.

It is often positioned in governmental policy on emergency agribusiness management as a last resort approach, when resource crunches or logistics render other options more difficult or too costly. In the past it has been used in natural disaster settings where instead of evacuating animals, ventilation shutdown is used to cook them alive. Or during peak COVID pandemic times, where supply chain disruptions resulted in backed up slaughterhouses becoming overwhelmed, entire flocks of chickens and herds of pigs were brutally killed in this fashion. 

In other cases, it seems to be selected for its speed and snap implementation. When done in the most basic and utterly heartless way of simply turning off air and shutting doors, the absence of any requirement for specialised personnel and niche equipment means it’s seen as an instant option. 

In 2022 in the United States, one of the world’s largest egg farms, Rembrandt Enterprises in Iowa, chose to use ventilation shutdown as a reaction to detecting a single case of AI in their factory farm, cooking over 5 million chickens trapped in their cages overnight. It took a staff of over 250 people nearly a month to drag all the bodies of the dead chickens from their cages, to clear and clean the shed afterward.

Kill by gassing

Another method is to crudely retrofit production sheds into on-farm gas chambers. Most often called ‘Whole House Gassing’, the lower section of a poultry shed is tented off with plastic curtains and liquid CO2, or similar, is injected inside. It evaporates and kills the chickens as they gasp for oxygen that isn’t there. C02 is often the most economical to purchase and convenient in that it is non-toxic when diluted with enough air, rendering any escaping gas unproblematic. It is also heavier than oxygen, so it effectively displaces the available oxygen and blankets the floors of sheds more easily, while not requiring complete whole-house sealing.

As it is delivered in liquid form at freezing temperatures, expertise and specific infrastructure is required to inject the gas into an enclosed space to achieve an even disbursement, so that gas concentration and exposure is level throughout the shed, instead of pooling at a localised single injection site. Only one injection site also produces a freezing effect for the chickens unlucky enough to be trapped nearby, and can consequently freeze those chickens to death by being exposed to a rush of liquid CO2. 

Even within the context of trying to kill a mass of animals at speed, death by hypothermia as an outcome is considered inappropriately “adversive”. Inexpert application of gas can also result in a highly distressing experience for the birds. If the onset of C02 (or mix of C02 and other gas) isn’t appropriately phased in, the sensation of suffocating, where birds bob their necks and gasp for air, is more pronounced and considered a poor welfare outcome. 

In some cases, gassing is done by a “containerised” method, when infected or exposed chickens are gathered into smaller containers which are usually pre filled with gas. In practice, this has looked like throwing or dropping chickens into a rubbish bin skip filled with gas. This means the birds at the bottom, exposed to the highest concentration of C02, have a horrendous death with a sudden and intense exposure to lack of oxygen, and are also smothered under the weight of the other chickens being piled on top. It also is more labour intensive, requiring manual catching and more handling of the live, possibly infectious chickens, and exposes them to brutal handling techniques as they are deposited into the containers, likely painfully injuring them before death. 

“Containerised” gassing with dedicated infrastructure is another model, but can have capacity and throughput challenges. Within business as usual in the egg production industry in New Zealand, hens who naturally go through a moult and take a pause in their egg laying cycles around 18 months old are killed, as they are no longer profitable. The hens’ lives are sadly considered to be worth so little it is often not economically attractive to send them to a commercial slaughterhouse, so mobile CAS (Controlled Atmosphere Stunning) units are used to kill the birds at this pause in their laying cycle. The chickens are captured by hand, carried by their feet upside down, loaded into crates which are then loaded into the gas module.

An additional downside to using C02, whole house or containerised, is that while it is the cheapest of the gas forms, in recent years there has been a global shortage of commercial grade C02, including the proportion manufactured domestically. The closure of Marsden Point, then the temporary closure of Todd Energy Kapuni (now operating a reduced capacity) saw local supply plummet. Global stocks available for import are still pushed. 

Inert gases, such as argon and nitrogen, are more technical to use, requiring more tightly contained whole house sealing and are generally more expensive as a consumable resource. Often a mixture of gases has been recommended as the least aversive for the birds while remaining highly effective, however, that approach requires further technical skill and more costly resources.

Killing by foam

A third category of depopulation method is to pump one of various types of expansion foam into the sheds. In the event of using a low expansion ‘wet’ foam, often referred to as firefighting foam, the blanket of foam covers the floor to smother the chickens alive in a dense layer that obstructs their airways, suffocating them to death as they thrash under the layer of bubbles. 

Another approach that is considered superior within the foaming category is ‘dry’ foam, or high expansion foam, where the bubbles are filled with an inert gas like nitrogen. As the birds thrash in the onset of bubbles around them, their wing movement bursts localised bubbles and releases the gas inside to render them unconscious before dying. This developing methodology still being evaluated, but is considered to show promise on the balance of speedily rendering unconsciousness with effective mortality. A gross notion, but an important one in the face of the distasteful consequences of factory farming.

What method of mass animal destruction did the Government choose?

When pressed by the media, MPI eventually disclosed it is killing around 200,000 chickens on site at the infected Southland egg farm using carbon dioxide gas over a period of 2-3 days. Media took photos of trucks bringing in large canisters of CO2.

At the time of writing (December 2024) the specifics of exactly how the gas is being used to kill are still hidden, and the devil really is in the details with this. Sudden exposure to high concentrations of C02 is brutal and causes extreme distress. This has happened in instances of trying to kill huge numbers of birds very rapidly, using skip bins and other large containers pre-filled with gas. Conversely, using purpose built CAS (Controlled Atmosphere Stunning) modules would inflict less overall suffering if implemented correctly.

CAS modules and similar infrastructure are considered the more sophisticated approach, with sometimes mixed gases and specifically phased controlled atmosphere stunning. The nuance here is what’s most significant, and so far the details about the mass killing have been redacted in information released and glazed over in what’s presented to the public. Are only dedicated CAS modules being exclusively used? Is any whole house or partial shed tenting with liquid injection being used? Prefilled containers with sudden exposure? All are methods using C02 with significant variations in how much distress and suffering is inflicted on the chickens. 

These distinctions are crucial. And importantly, Kiwis should also be told if the controversial and barbaric Ventilation Shutdown would ever be used or is it off the table no matter what? Or death by foaming, as has been used in Australia? What will MPI do if there is a ‘catch fire’ moment with this infection and manual handling methods are simply not achievable?

The Official Information Act response from Biosecurity NZ wouldn’t rule any particular methods of depopulation out. When specifically asked if ventilation shutdown will be off the table, MPI declined to answer. 

How would bird flu affect our native and wild birds?

There is significant risk to our precious native, and generally wild, bird population if the HPAI H5N1 were to arrive. This current strain has been linked to the death of well over half a million wild birds. The specific level of lethal impact this particular bird flu strain would have on our indigenous species is as yet unknown, given our animals have not yet been exposed to the HPAI H5N1 virus.

How do we know when bird flu comes to New Zealand?

Surveillance is underway to monitor and pick up avian influenza. The Dunedin Wildlife Hospital is monitoring migratory arriving birds, and shorebirds in general, testing them for bird flu. Those birds tested for the flu included various penguin species, New Zealand falcons, albatross, prion and Australian harriers. 

In addition, MPI’s Animal Health Laboratory has tested samples from at least 23 different species of birds resulting from investigations. Those sampled include petrels, pukeko, yellow-eyed penguins, swans, sparrows, tui, chickens, Canadian geese, sooty shearwater and multiple varieties of ducks and gulls. To date, all these have been negative for any HPAI.

The Ministry says it’s also working with Fish & Game to plan for sampling water fowl (ducks, geese, swans etc) during the upcoming summer months. 

In general, the birds most at risk of contracting a recently arrived infection are those who live in dense colonies, in large groups in close contact, for example, gannets, gulls and terns.

What is being done to protect native birds?

The Department of Conservation (DOC) is working on testing a targeted vaccine to combat the virus. It has been used successfully in zoos in Europe, and is still being tested. The first trial doses were administered in January 2024 to 50 birds, including takahē, kākāpō, tūturuatu, kakī and kākāriki. The participating birds are part of DOC’s captive breeding programmes.

Realistically, the Department/DOC admits it’s not practical or indeed even possible to effectively vaccinate and protect all our wild native birds, so they are currently focussed on those most endangered and in monitored or captive environments and breeding programmes.

“DOC is focusing on threatened species that are reliant on captive breeding or intensive management for species survival”.

Can people get bird flu? 

Yes, humans can now also be infected with Avian Influenza. What started out only in birds then jumped to animal/non-human mammals, and then human mammals. 

The World Health Organisation says “Animal influenza viruses are distinct from human seasonal influenza viruses and do not easily transmit between humans. However, zoonotic influenza viruses – animal influenza viruses that may occasionally infect humans through direct or indirect contact – can cause disease in humans ranging from a mild illness to death.”

When compared to the virality and speed of the spread of bird flu strains between animals, so far relatively few people have contracted the disease. Currently, the risk to human health is classified as low, but still of significant concern should the virus continue to mutate and pick up speed in human infections.

Background of human infections of Avian Influenza in the current outbreak

Back in 2020, fewer than 20 cases of a bird flu influenza viral infection in humans were reported. Most cases were detected in China, with a handful spread between Russia, Hong Kong and Senegal, according to the US Centre for Disease Control. The next year became more deadly, with a jump in both case numbers (to more than 60) and now with significant mortality. At least 19 people died, mostly with the H5 strain. 

Through 2022 and 2023, cases in humans continued to spread around the globe, including fatalities. The majority of cases have been in dairy farm workers in the United States who were likely exposed through working in close contact with infected mammals – the dairy cows. Infection in humans was also documented in Mexico, the UK, Spain, India, Vietnam and Cambodia. 

Earlier in May this year, Australia identified a human case of H5N1 infection, in a child returning to Australia after an overseas trip to India. The child went on to recover and no further human cases were found. 

In June of 2024, a man in Mexico had the first fatal human case of H5N2 (slightly different to H5N1). While the 59 year old did have prior health conditions, the route of his exposure to bird flu was never determined, which was concerning.

According to the World Health Organisation, “globally, from 1 January 2003 to 19 July 2024, 896 cases of human infection with avian influenza A(H5N1) virus were reported from 24 countries. Of these 896 cases, 463 were fatal (CFR* of 52%)” (*Case Fatality Rate)

In September, a man in Missouri in the United States was the first human case of contracting H5N1 bird flu without a known exposure to sick or infected animals. His infection was picked up though routine flu testing services, and was the first time H5 has been detected without clear causation. The patient was hospitalised, but made a full recovery. 

Who is most at risk of getting a bird flu? 

People most at risk of contracting the disease are those working in close contact with animals in production environments battling AI. Dairy cattle workers in the United States in particular, and poultry workers in various countries facing outbreaks. 

Transmission from birds, or infected animals in general, to humans can occur through:

• handling of infected animals, live or dead
• close contact with the faeces, respiratory secretions or saliva of infected animals 
• consumption of infected and uncooked animals
• handling of contaminated products like floor litter and farming equipment

Does Australia have Bird Flu?

Yes and no. Our neighbour across the Tasman Sea, Australia, has a complex situation when it comes to current bird flu status. Australia does have some types of bird flu, but not others, just like New Zealand now has one confirmed HPIA strain.

Historically, since the first occurrence was picked up in 1976 on a poultry farm in Melbourne, Australia has battled flare ups of various subtypes of the H7 bird flu. It has cropped up again, significantly, in 2024, resulting in well over a million birds across farms in Victoria, New South Wales and Victoria being depopulated – killed – as an attempt at disease control.

The main strain of current global concern, H5N1, did make a brief and startling appearance in a toddler in Australia, in May of 2024. A child was picked up to have the infection after travelling overseas to India. She went on to make a full recovery and no further infections in humans or animals have been detected since. 

As of September 2024, Australia does not currently have any detected cases of an HPAI H5N1 Avian Influenza.

Who doesn’t have H5 Bird Flu?

The current problematic outbreak of AI, specifically a HPAI version of H5N1, started in 2020 in the northern hemisphere in Europe. In the last four years it has reached almost every country, now including subantarctic islands and the Antarctic mainland. 

As of December 2024, New Zealand, Australia and the Pacific Islands remain currently free of the most currently concerning, and deadly, HPAI H5N1 strain. The strain detected here earlier in the month was an H7 strain, not H5.

How infectious is bird flu and how is it transmitted?

How do birds catch bird flu?

Bird flu is highly infectious and easily transmitted between animals. Like most viruses, it is shared through bodily secretions, such as through faeces, respiratory secretions or feather contact. Ingestion of sick animals by birds pecking at each other (otherwise known as cannibalisation) and at open wounds are also sources of infection. Contaminated shared food and water supplies, floor litter (like straw or sawdust) and general farming equipment and infrastructure can also spread the virus. 

Considering how densely packed chickens bred for meat and hens kept for eggs are in New Zealand (in both sheds, barns and with some hens locked in colony cages) the virus could spread quickly through a flock. 

In response to an infection outbreak, conditions in our current farming and production practices would likely increase. As free ranging chickens could be exposed to the virus from wild birds outside, this is often managed overseas by removing free ranging access for the chickens. Birds previously permitted to free range outdoors may likely be kept inside at all times.

Understanding the virus science and its survivability

Influenza viruses are lipid-enveloped RNA viruses and how stable they are varies by subtype. Generally, influenza viruses are considered ‘fragile’, however some serotypes – a distinguishable strain of a microorganism – can remain active under certain conditions. 

Heat is one way the virus is inactivated, or killed. Pasteurisation and thorough cooking deactivates the virus. It is sensitive to ultraviolet light (sunlight) but it needs a long exposure period, exceeding an entire day of sun, (around 14+ hours), to inactivate. 

The virus remains viable for longer in cooler conditions with higher moisture levels. One study found the virus was detectable in wet manure and animal faces after 105 days, and in landfill almost two years later where there were optimum conditions of a neutral pH and low temperature. 

In water, acidity (pH) and saline levels as well as water temperature are the key factors determining how long the virus can live. When these factors are raised, bird flu survives for less time, with some variance between strains. AI viruses have been isolated from both lake and on-farm water reserves where waterfowl are present. In 22 °C water, the virus has been observed as infective in lake water for up to 4 days, and for more than 30 days at 0 °C. As lower temperatures prolong viability, the virus can remain active in ice and frozen bodies of water. 

The ability of the virus to persist in certain conditions demonstrates the burdensome level to which production facilities must be fully sanitised following a bird flu infection outbreak. 

First, all the infected and exposed chickens are killed then all materials, the dead bodies as well as contaminated floor litter, sawdust or straw, must be destroyed, generally on-farm to prevent possible airborne spread if materials were transported. Overseas, this has generally been done with incineration or on site composting. Both are heat-generating approaches to kill the virus as quickly as possible. The barren interiors of sheds are then sanitised. Effectively, commercial farms attempt to enact a ‘clean slate’ approach after an outbreak.

Can you eat chicken meat or eggs from infected animals?

Following a flare up of bird flu in overseas markets, supermarkets often enforce temporary purchasing limits for shoppers on affected products, such as eggs and chicken meat. Earlier this year in Australia, McDonald’s outlets temporarily shortened their breakfast service window by 90 minutes, reducing the number of egg McMuffins that could go out the door. 

Purchase quotas and reduced menus are the result of a suddenly reduced domestic supply, as entire flocks of infected or potentially infected birds are killed. Exposed flocks and all contaminated materials, such as floor litter and sawdust, are generally destroyed on farm sites through either incineration or composting, as both methods generates heat to kill the virus.

During an outbreak of Avian Influenza, the virus replicates inside the chicken’s oviduct (the internal tube of passage for eggs). Infected, unwell birds will often stop or reduce laying, however both LPAI (low pathogenic) and HPIA (highly pathogenic) viruses have been detected in yolks and albumen (egg whites), as well as on the shell surface of chicken eggs. Faecal contamination is thought to be the most likely route for virus transmission, as eggshells are porous, making non-pasteurised or uncooked eggs a theoretical source of the virus. Exposed products, such as eggs, are generally destroyed to ensure they are free of the virus, otherwise, they would need to be cleaned and heat treated.

Are products at supermarkets safe to eat?

For products that are still on shelves, the New Zealand Ministry For Primary Industries says “there is no evidence that people can be infected with HPAI by eating thoroughly cooked poultry (like chicken, turkey, or duck), or foods that contain them or eggs.” As AI is inactivated through heat, the virus cannot survive cooking temperatures.

Food Standards Australia New Zealand (FSANZ) says that bird flu doesn’t present an increased food safety issue, provided people continue with proper hygiene practises in the kitchen, such as thoroughly washing items and hands, as well as robust cooking with high temperatures. “Thorough cooking means heating food to an internal temperature of: 75°C for at least 30 seconds, or 70°C for 3 minutes, or 65°C for 15 minutes”, FSANZ specifies. 

Bird flu does not present an increased or new food safety hazard for people beyond the usual food safety concerns around salmonella and campylobacter on chicken carcasses. However, customers may experience some turbulence in product availability due to a potentially sharply fluctuating supply. As New Zealand does not import whole chicken, eggs in-shells or fresh chicken meat, our supply is vulnerable to local market conditions as it is domestically produced. 

How can the public help with the efforts to detect bird flu?

MPI is also asking for the public’s help, to be vigilant in reporting any concerning unwell bird sightings. In the event of noticing birds exhibiting signs of distress or strange behaviour, first contact your vet to be assisted in ruling out other causes. Note that it’s important not to handle unwell birds. In domesticated waterfowl – like ducks and geese – HPAI symptoms are usually related to the nervous system, and often display as involuntary movement, a lack of coordination, trembling and blindness.

If you see three or more severely sick or dead wild birds in one group or flock, report it immediately to MPI’s hotline on 0800 80 99 66. Do not handle the birds. Do try to provide as much detailed information as possible, such as a GPS location as well as photos or videos and a count or estimate on the number of birds affected, or in the area. The public tip line is monitored by Biosecurity New Zealand.

How to recognise bird flu on a farm? 

New Zealand’s Ministry For Primary Industries (MPI) advises the most obvious sign of outbreak is a sudden spike in dead birds in a short timeframe. However, this is not as clear an indicator as one might like. Within business as usual in poultry farming practice, it’s not uncommon to have dead and dying chickens. One MPI report found that upwards of 6,000 chickens die in poultry sheds in New Zealand every day, from being so chronically unhealthy while living in such stressful conditions. 

In addition to a sudden a cluster of dead birds, other symptoms to look for in farmed birds, chickens and turkeys include this list from MPI:

• “lethargy or a reluctance to move,
• reduced appetite,
• droopy head, paralysis, or incoordination (neurological signs),
• darkened or swollen face, comb, or wattle (“cyanosis”) from lack of oxygen,
• coughing, panting, and nasal secretions,
• unexpected drop in egg production,
• bruising or haemorrhages,
• severe diarrhoea,
• a silent or “too quiet” poultry shed.”

Which animals can get bird flu?

The last few hundred years have shown us that the various Avian Influenza (AI) strains are particularly slippery and problematic due to their ever-changing nature, with new serotypes developing. What started as only a ‘fowl plague’ has since expanded to include infecting numerous mammals, jumping from species to species. 

Overseas, the current main problem strain of HPAI H5N1 has been detected in around 50 species of mammals, both land and sea animals. From cows, mice, bears, alpacas, goats and hedgehogs to seals, sea lions, dolphins and otters. Canada has reported cases of domestic pet cats being infected, as has Poland and South Korea. One theory is this infection was contracted after suspected ingestion of contaminated raw pet food containing infected poultry.

Over 200 herds of dairy cattle spread across various states of North America have been infected, mostly this year. Some herds were killed while others recovered after 2-3 weeks of supportive care and quarantine. The leading producer of Europe’s fur products, Finland, has been mass culling their infected animals, foxes and minks, on fur farms. 

As AI is spread through bodily secretions, such as through faeces, saliva and respiratory secretions, infection can rapidly spread through a concentration of animals living in close quarters. Animals who move freely, and often undetected, who can potentially get into shared food and water sources and contaminate them, such as mice and hedgehogs, are also a vector for infection spread.

Some animals are able to recover from even an HPAI case of bird flu with appropriate vet care, seclusion and sanitisation measures. Sadly, this will never happen with chickens reared commercially. The poultry industry places so little value on their individual lives, that their fate is to be mass killed as a control measure in an attempt to curb the spread of further infection.