It kills farmed birds really fast – they’re usually dead within 24 hours of showing signs of infection, and we’re seeing mass mortality events.
Biosecurity
Once H5N1 has entered a poultry population, all the birds are doomed. Among poultry H5N1 is highly infectious and very lethal. Therefore entire populations are culled with carbon dioxide or by drowning the birds in a water-based foam. Another method, called ventilation shutdown plus (VSD+), consists of turning off the oxygen supply and increasing the heat until the birds die. Some scientists argue that possible survivors of the infection should be bred to create poultry resistant to avian influenza. Indeed some birds survive, like some Northern Gannets, where a change of eye color from blue to black indicates a previous H5N1 infection.
So far at least 140 million chickens have died, but the actual number by now is probably well over 200 million. While those numbers are high, this is not even one percent of the global chicken population of over 30 billion, sustained by demand of billions of consumers. As long as H5N1 keeps spreading, the culling will continue and the numbers will rise.
More than 140 million birds have died and hundreds of millions of pounds have been spent in the past year in the US, UK and EU in tackling bird flu, as some experts said continual culling was “morally” wrong.
In 2020, the global chicken population was over 33 billion birds. Approximately 46 percent of these were in Asia.
Laborers worked for a month disposing of birds killed in a gruesomely inhumane manner. Then they found they too were disposable
It doesn’t take experiments to realize that slowly cooking to death and suffocating birds is cruel, yet the poultry industry funded university researchers to optimize this mass-killing method so large facilities could cheaply kill entire flocks on a routine basis.
So, live and wet markets in rural Asia are the origin and later migratory wild birds were, and are, the major spreading factor of HPAI over the past nearly three decades.(...)
How, then, are the commercial birds, in the developed world or in a modern poultry operation, a petri dish for the next pandemic? Especially given that the policy is often to kill infected birds immediately, dispose of them properly and then enact strict biosecurity measures to limit disease spread.
Quammen’s argument hopes to appeal to a reader who is: afraid of another pandemic, under-educated on animal agriculture and probably already biased against the agriculture industry. Times readers are, after all, perpetually coached by its editorial pages to feel bad about eating meat or using animal products. The author is certainly an expert on wildlife, but perhaps not domesticated animals.
How, then, are the commercial birds, in the developed world or in a modern poultry operation, a petri dish for the next pandemic? Especially given that the policy is often to kill infected birds immediately, dispose of them properly and then enact strict biosecurity measures to limit disease spread.
Quammen’s argument hopes to appeal to a reader who is: afraid of another pandemic, under-educated on animal agriculture and probably already biased against the agriculture industry. Times readers are, after all, perpetually coached by its editorial pages to feel bad about eating meat or using animal products. The author is certainly an expert on wildlife, but perhaps not domesticated animals.
Four main risk factors for the emergence and spread of these diseases were identified. Bulleted first was “Increasing demand for animal protein.” This has led to what the Centers for Disease Control and Prevention (CDC) refers to as “the intensification of food-animal production,” the factor blamed in part for the increasing threat. The WHO, OIE, and FAO all implicated industrial poultry production as playing a role in the H5N1 crisis. (...) “We are wasting valuable time pointing fingers at wild birds,” the Food and Agriculture Organization stated, “when we should be focusing on dealing with the root causes of this epidemic spread which . . . [include] farming methods that crowd huge numbers of animals into small spaces.” In the United States, the average numbers of animals on chicken, pig, and cattle operations approximately doubled between 1978 and 1992.
Under a regime of biosecurity, living beings are flattened into momentary vectors of capital or disease. Containment of all kinds becomes the goal. These new frontiers in biosecurity are accompanied by a cultural pendulum that swings from normalcy to alarm alongside the constant search for an elusive sense of security in our ever-uncertain world.
But if biosecurity is an ideology, a practice, and an economy that makes the nation-state secondary to the forces of tech capital and technology, its recent appearance is testament to its own fragility. The fact that biosecurity needs to exist is a reminder that the project to contain and control the unpredictability of living beings is ultimately futile.
The more I learned about the dizzying web of international trade agreements, foreign-policy decisions based on agricultural trade, investments, technological change, and ecological devastation wrought by multinational agribusiness over the past two decades, the more surprised I was that a global pandemic hadn’t happened sooner. Global free trade of agricultural commodities is set up to encourage industrialization of farming. The ecological and human health consequences of factory farming are dire, especially in terms of the incubation of emerging pathogens, as epidemiologist Rob Wallace documents in his book Big Farms Make Big Flu.
At the time, health services who came to “depopulate” buildings were so overwhelmed by the scale of the task that many farmers had to euthanise their poultry themselves, sometimes with no other means than cutting off ventilation in the buildings. These culls undermined not only the viability of the poultry industry, but also animal-welfare standards and farmers’ morale.
A total of 25,774 pooled samples were collected through active surveillance at 167 LBMs in 24 provinces; 36.9% of pooled samples were positive for influenza A, 3.6% A(H5), 1.9% A(H5N1), 1.1% A(H5N6), and 0.2% A(H5N8). Influenza A(H5) viruses were identified January–December and at least once in 91.7% of sampled provinces.
The first wave, which occurred from 2005–2010, was caused by H5N1 viruses and 55.2 million poultry died or were destroyed. The outbreaks that occurred during this period were mainly reported in Asian countries, although some African and European countries were also affected. The second wave, which occurred from 2011 to 2019, was caused by multiple subtypes of H5 viruses and 139.9 million poultry died or were destroyed. The outbreaks in this period were reported in Asia, Europe, Africa, and North America. The third wave started in 2020 and was mainly caused by H5N8 and H5N1 viruses; 193.9 million poultry died or were destroyed as of the end of November 2022.
Of the 389 million poultry that died or were destroyed, H5N1 viruses were responsible for 204 million, H5N8 viruses were responsible for 111 million, and the other 74 million poultry losses were caused by other H5 viruses. Of note, 92.6 million, 54 million, 39.6 million, and 7.7 million poultry died or were destroyed in Europe, North America, Asia, and Africa, respectively, since 2020. The large number of birds that died or were destroyed in the third wave in a relatively short period of time suggests that the ongoing third wave will be much more serious than previous ones, if control measures taken in Europe and North America do not change.
It is one of the worst forms of cruelty being inflicted on animals in the US food system — the equivalent of roasting animals to death — and it’s been used to kill tens of millions of poultry birds during the current avian flu outbreak.
As of this summer, the most recent period for which data is available, more than 49 million birds, or over 80 percent of the depopulated total, were killed in culls that used VSD+ either alone or in combination with other methods, according to an analysis of USDA data by Gwendolen Reyes-Illg, a veterinary adviser to the Animal Welfare Institute (AWI), an animal advocacy nonprofit. These mass killings, or “depopulations,” in the industry’s jargon, are paid for with public dollars through a USDA program that compensates livestock farmers for their losses.
USDA regulations specify that VSD+ is meant to serve as a stopgap when one of two other depopulation methods aren’t available in time for producers to rapidly cull their farms: firefighting foam, which is sprayed over the birds to suffocate them, or carbon dioxide poisoning (neither of these is painless, especially the former, but both are widely considered less cruel than ventilation shutdown).
But getting access to these methods on short notice requires advance planning — having standing contracts with companies that can supply CO2 gas, for example — that neither the meat industry nor its regulators appear interested in ensuring is in place. VSD+, on the other hand, can more easily be arranged in a pinch because heaters can be rented off-the-shelf from equipment companies. When disaster strikes, livestock producers that failed to prepare can simply say they had no choice but to kill their animals with heatstroke.
But getting access to these methods on short notice requires advance planning — having standing contracts with companies that can supply CO2 gas, for example — that neither the meat industry nor its regulators appear interested in ensuring is in place. VSD+, on the other hand, can more easily be arranged in a pinch because heaters can be rented off-the-shelf from equipment companies. When disaster strikes, livestock producers that failed to prepare can simply say they had no choice but to kill their animals with heatstroke.
Poultry Vaccines
Due to fears of a "leaky" vaccine causing the undetected spread of H5N1, poultry has so far rarely been vaccinated in Europe and the USA. After all outbreaks are easily detectable and depopulation denies the virus any possible short-term advantages. The HVT-H5 vaccines from Ceva Sante Animale and Boehringer Ingelheim Animal Health have recently been shown to be 100% effective. This may lead to a change of vaccination policies in the USA and Europe. It is worth noting that the more risky Chinese approach may have reduced the number of human infections, but has not entirely stopped the outbreak.
Both HVT-H5 vaccines have been found to be 100% effective in preventing disease and mortality after infection with the HPAI H5N1 virus. This is in contrast to the other two vaccines in which disease was observed.
Farmed poultry are not routinely vaccinated against avian influenza in the EU. However, the European Commission has asked EFSA to provide a scientific opinion on possible vaccination and monitoring strategies in Europe.
Vaccines are already available in other countries, including China, Egypt, Indonesia, Italy, Mexico and Vietnam, and some nations are vaccinating their commercial flocks.
However, in the United States, not all poultry experts are ready to use a vaccine, even if one becomes available – at least, not yet. Instead, their focus remains on eradicating the virus.
A
series of vaccines have been developed and over 50 billion
doses of these vaccines have been used in China and other
countries. Most importantly, the vaccine seed virus has
been updated to ensure the best protective efficacy to the
prevalent circulating strain. The vaccination strategy has
been effective and has played an important role in reducing
the incidence of H5N1 in poultry and markedly reducing
the number of human cases. Although progress has been
made in the control of avian influenza viruses, circulation
of these viruses has not been eliminated from poultry. It is
worth noting that complete control and eradication of
H5N1 HPAIV viruses can only be ultimately achieved by a
combination of vaccination, improved biosecurity,
extensive surveillance and an effective monitoring
programme.
A
series of vaccines have been developed and over 50 billion
doses of these vaccines have been used in China and other
countries. Most importantly, the vaccine seed virus has
been updated to ensure the best protective efficacy to the
prevalent circulating strain. The vaccination strategy has
been effective and has played an important role in reducing
the incidence of H5N1 in poultry and markedly reducing
the number of human cases. Although progress has been
made in the control of avian influenza viruses, circulation
of these viruses has not been eliminated from poultry. It is
worth noting that complete control and eradication of
H5N1 HPAIV viruses can only be ultimately achieved by a
combination of vaccination, improved biosecurity,
extensive surveillance and an effective monitoring
programme.
The technical difficulty of vaccinating poultry lies in their short lifespan compared to other farm animals (around 60 days) and the fact that two doses are required for the vaccine to be effective.
The results were deemed sufficiently positive for the Ministry of Agriculture to announce a vaccination campaign for farmed ducks in autumn 2023, allowing for a manufacturing time of 6 to 8 months.
All chickens are vaccinated, save for a hundred “sentinels” that are meant to die first when a new virus reaches the farm. The Chinese characters used to describe these chickens, “shaobingji,” literally translate as “chickens that whistle like soldiers.”
We find that lineage transitions among host types are lagged and that movements from wild birds to unvaccinated poultry were more frequent than those from wild birds to vaccinated poultry. However, we also find that the HA gene of the AIV lineage that circulated predominately among Chinese poultry with high vaccination coverage underwent faster evolution and greater nonsynonymous divergence than other lineages. Further, this Chinese poultry lineage contained more codons inferred to be under positive selection, including at known antigenic sites, and its rates of nonsynonymous divergence and adaptative fixation increased after mass poultry vaccination began.
Two doses of vaccine must be administered. The first is given to ducklings at 10 days of age or more, with the second administered 18 days later. Vaccination is supervised by a veterinarian designated by the farmer.(...)
Two vaccines have been granted temporary authorizations for the campaign, Volvac B.E.S.T. AI + ND from Boehringer Ingelheim Animal Health France and CEVA Response AI H5 vaccine from Ceva Sante Animal, with BI winning the first supply tender.
Two vaccines have been granted temporary authorizations for the campaign, Volvac B.E.S.T. AI + ND from Boehringer Ingelheim Animal Health France and CEVA Response AI H5 vaccine from Ceva Sante Animal, with BI winning the first supply tender.
With both vaccines, only one vaccinated animal put in direct contact with vaccinated inoculated
animals was detected positive, for oro-pahryngeal shedding only, and at a single time-point.
Animal health officials in France today reported an avian flu outbreak at a duck farm on which the birds had been vaccinated in November 2023 as part of the country's initial rollout of the poultry vaccine, which marked the first in Europe. (...) It's not clear, however, if the ducks on the outbreak farm had received the third dose.
France's agriculture ministry has ordered that farm ducks in high-risk areas receive a third dose of avian flu vaccine owing to new scientific evidence, according to Reuters, which cites the country's farm ministry.
USDA’s Agricultural Research Service (ARS) began
testing candidate vaccines for H5N1 in poultry in 2023.
ARS scientists evaluated one H5N1 vaccine developed
in-house by USDA and four commercial HPAI vaccines.
These studies showed that the five vaccines reduced
oral and cloacal virus shedding significantly and
provided near 100% clinical protection in chickens;
however, they continue to rely on a two-dose regimen,
which can be impractical for distribution to flocks.
Eggs
Egg prices are influenced by bird loss due to avian influenza. While food safety recommendations aim to prevent Salmonella infections, the requirements for H5N1 heat inactivation are very similar. Just a few degrees make all the difference. The deficits in consumer egg preparation safety cause around 250.000 Salmonella infections in the USA each year. While a few percent of raw eggs undergo in-shell pasteurization, this doesn't affect regular eggs and the risks associated with the consumption of raw eggs.
In-shell pasteurization of HPAIV-positive eggs is predicted to inactivate the virus and result in negligible risk to public health. Data from USDA’s Agricultural Research Service show that FSIS time and temperature recommendations, at the standard industry moisture content, for egg product processing
are sufficient to inactivate HPAIV, therefore this risk assessment model does not
quantitatively assess the risk of illness from HPAIV-contaminated egg products.
H5N1 virus lost infectivity after 30 min at 56°C
Cook raw shell eggs that are broken for immediate preparation and service to heat all parts of the food to a temperature of 63°C (145°F) or above for 15 seconds.
In the United States, eggs are not required to be pasteurized. Hence, less than 3% of the eggs in the country are pasteurized. The standard pasteurization method (57°C, 57.5 min) uses a long thermal process that increases the cost of the product and affects its quality.
In 2022, input prices were high overall, putting upward pressure on egg prices. Recent reports and news articles often cite avian influenza and bird loss as the primary cause of high prices. These reports are not necessarily wrong. However,our analysis reveals a very important issue that has not been thoroughly discussed. That is, current decreases in flock size due to avian influenza may be compounding the effects of higher input prices.
Based on our estimates, $0.31 of the overall price increase was due to relative bird loss, $0.51 was due to natural gas prices, and $0.52 was due to the increase in feed cost (...) While bird loss was the most important determinant based on the estimated impact, it was not most important in explaining the annual increase in prices. Of the three exogenous variables, the change in bird loss was smaller overall, 19.4% versus 37.4% and 143.3% for feed cost and natural gas prices, respectively.
70% of people don’t know the safe cooking temperature for foods such as poultry and egg dishes, that may be contaminated with Salmonella and Campylobacter; and
one in four adults are taking a food safety risk by eating raw or undercooked egg dishes especially as 12% of them eat these foods at least monthly.
Consumption of well-cooked eggs accounted for 84%, consumption of soft-boiled eggs for 12%, and consumption of raw eggs for 4% of the total amount of eggs consumed.
In the United States, Salmonella infections cause 1 million foodborne illnesses each year and contribute to 35% of all hospitalizations and 28% of all deaths related to foodborne illness. (...) The CDC estimated that 24% of foodborne disease outbreaks caused by Salmonella and 64% of outbreaks caused by Salmonella Enteritidis were attributable to contaminated eggs from 1998 through 2008.
Prices for farm-level eggs fell by 23.2 percent in March 2024 after increasing by 53.8 percent in February. As you know, the outbreak of Avian Flu that began in 2022 contributed to elevated egg prices in some supermarkets up to $7 a dozen. The Bureau of Labor Statistics reports the national average in cities hit the high point in January of 2023 at $4.82 for a dozen grade A large eggs. In March 2024, prices for farm-level eggs were 35.7 percent lower than March 2023, when prices remained high following the initial onset of HPAI in 2022. After the egg prices peaked in January 2023, they declined or stabilized through much of 2023. Now, with new confirmations of Avian Flu in November 2023, we are witnessing steady price increases.
Seemingly every day there is another announced infection site, which not only physically reduces the actual number of egg layers, but also casts a negative psychology over the entire egg market. The reaction to supply stress is price increase.
Poultry Litter
Poultry litter consists mostly of poultry excrement and is used as feed for livestock. Unfortunately poultry excrement contains many nutrients and is very cheap. This results in strong economic incentives to replace around 20% of livestock feed with poultry litter.
It seems ghoulish, but it is a perfectly legal and common practice for chicken litter — the material that accumulates on the floor of chicken growing facilities — to be fed to cattle.
UC Davis’ Payne said that in California, poultry waste is processed at high virus-killing temperatures, so it is unlikely to be a concern. The practice is banned in the United Kingdom, European Union and Canada, where fears of spreading bovine spongiform encephalitis — mad cow disease — made such practices seem too risky.
Representatives of the beef and poultry industry argue that the overall costs to the beef industry – and, ultimately, the consumer – would far outweigh any ‘”limited” potential safety gains from banning poultry litter as a cattle feed. They also claim that any ban would exacerbate the existing problem of the mass disposal of poultry litter from factory farms. In defending their right to feed poultry litter to cattle, the National Cattlemen’s Beef Association recently said that “we must continue to look to the science to avoid over-regulating the industry and creating policy that doesn’t meet our objective of a safer animal health system.”
The fact that certain elements within the food and farming industry are willing to publicly defend the feeding of poultry litter to cattle – that is chicken feces, feathers and other poultry debris collected from the floors of factory farms – on the basis that this represents a “safer animal health system” is an appalling indictment of the state of US food and farming. It also is a stark warning to us all of the huge chasm that has emerged between how most of us think our food is being produced and the appalling practices that are justified by those who are so deeply embroiled in the drive to produce ever cheaper meat that they no longer have any sense of what is accepted as the norm.
Deep in the remote Maili Kumi Location in Buuri, Meru County, a state of the art chicken farm is thriving. Here, you can catch a glimpse of an unlikely friendship that has made the farm a household name among residents. The farm rears about 20,000 chicken in automated cages laying on a one-acre farm. “We have around 92 pigs, so the relationship between the pigs and chicken, is that the pigs consume poultry waste,” said (...), the farm manager.
Animal wastes represent a vast reservoir of cheap nutrients, particularly for ruminants. In most countries, waste, particularly from poultry, is easily collected, as it is concentrated in small areas, and its cost, as a raw material for feed, is generally the cost of transport alone. The only expensive item may be processing, but this cost is relatively small and is recoverable from the profit arising out of the low original cost. Feed costs for dairy or beef cattle usually represent 50–80% of the total production costs; this can be reduced to 20–40% by utilizing these new feed resources as donors of protein, minerals and other nutrients.(...)The calculated mean energy values of animal wastes for ruminants, estimated in Table 8, indicate that only broiler manure and broiler litter exhibit a TDN value comparable to conventional feed ingredients (Müller, 1975e). The other livestock wastes are low in feed energy, at levels comparable to crop residues.
The economics of production results obtained showed that it was more economical to raise pigs using broiler litter at 20% of the diet. The results obtained from this study showed that processing methods such as ensiling, composting and sun-drying improved the nutrient composition of broiler litter and more over, processed broiler litter can be included up to 20% in the diet of growing pigs without any deleterious affect on the performance, hematological indices and economics of production in the diet of growing pig in the tropics. (...) For the test ingredient, the crude protein which was affected by processing (p< 0.05) ranged from 19.2% to 26.9%. Unprocessed broiler litter had the lowest value while highest value occurred with ensiled broiler litter.
Following a thorough review of the available literature concerning the use of broiler litter in both beef and dairy cattle diets, there appears to be no more health risks to animals or indirectly to humans from properly processed broiler litter than from any other source of cattle feed. The rumen (stomach) of a beef animal does an excellent job of breaking down and converting broiler litter into nutrients, which can then be absorbed and used by the animal. However, public perception regarding food safety can be influential. Many changes in agriculture have resulted from public fear and public perception rather than from scientific data and accurate information. Regulations and safety recommendations are detailed later in this publication to help ensure correct usage of broiler litter in livestock diets. If you feed diets containing broiler litter to cattle, be aware of potential public relations problems. Broiler litter is as safe as any other livestock feed if processed and handled properly. Still, be aware of public concern in using poultry waste in your livestock operation.
The maximum periods for viral survival were observed in samples stored at +4°C in all tissue types and were 240 days in feather tissues, 160 days in muscle, and 20 days in liver. The viral infectivity at +20°C was maintained for a maximum of 30 days in the feather tissues, 20 days in muscle, and 3 days in liver.
The quantitative importance of the feather excretion route, compared to the respiratory and digestive shedding routes, still needs to be assessed. Nevertheless, although a definitive conclusion is still premature, the intensity of the viral signal detected in the feather fraction identified in dust samples is remarkable. Current data available in chicken suggest that feather particles make up as much as 10% of the total mass of the dust present in poultry houses, underlying the quantitative importance of animal exposure to this type of substrate.
The virus survived up to 18 h at 42 °C, 24 h at 37 °C, 5 days at 24 °C and 8 weeks at 4 °C in dry and wet faeces, respectively.
Adding broiler litter to beef cattle rations at a level of 20% or higher (as fed basis) generally meets the animal's needs for crude protein, calcium, and phosphorus. (...) Broiler litter to be used for cattle feed should contain at least 75% dry matter. If litter contains less than 70% dry matter, wet spots and mold can be problems. Since litter may contain scrap metal, the material should be run through a hammermill equipped with a magnet to remove objects that may cause hardware disease. In addition, the material should be screened to remove pieces of wood, glass, etc.
Because of its high nutrient content, poultry litter is usually applied to agricultural land as fertilizer with an economic value of $20 to $30/ton. (...) In the 1960s researchers in Virginia brought attention to the economics of feeding broiler litter to beef cattle. Feed quality litter is high in protein and minerals but low in energy relative to grain or high quality forage. If used as a protein and mineral supplement in a feed ration, feed quality broiler litter has a value about $100/ton; soybean and cottonseed meal are valued at $200/ton. When fed at a 1:1 ratio with corn to 550-pound heifers, broiler litter has a value of $106/ton.
Poultry wastes may serve as an important source of energy also in beef cattle feeding. Broiler litter with peanut hulls or wood shavings as base material was shown to contain about 60% TDN, and 2440 kcal. digestible energy and 2181 kcal. metabolizeable energy per kilogram, dry basis, for ruminants. (...) Although a potential pathogen problem due to bacteria in animal waste does exist, processing waste should destroy these potential pathogens. FDA researchers reported that heat processing of broiler litter at 145 F for 60 minutes destroyed the four organisms studied, namely, S. typhimurium, E. coli, Arizona . and S. pullorum. (...) Ensiling a mixture of one-third broiler litter and two-thirds of high moisture corn lowered coliform numbers to the level in corn grain ensiled alone. Texas workers have shown broiler litter silage tested negative for salmonella, staphylococcus and coliforms. South Carolina workers found that ensiling of broiler litter destroyed salmonella. Recent research at Auburn indicates that ensiled materials should reach a pH of less than 5 in order to kill salmonella. Apparently due to the high ammonia level it is rather difficult to reach a pH of less than 5 without additional materials such as corn grain or whole plant corn forage. It appears that the addition of small amounts of material such as corn grain or molasses would be helpful.
The federal government does not regulate poultry litter in animal feed, and in many states — including Missouri, Alabama and Arkansas — there are no requirements or regulations regarding contamination or processing.
It is a premium product used to help recycle waste into a sustainable product.
Genetically Modified Chickens
A promising approach is to genetically modify chickens to achieve complete immunity. This is done by disabling the production of naturally occurring proteins that the virus needs to replicate. It is uncertain how well the chickens will fare with several proteins disabled. While more testing is required, the first completely immune chickens could reach consumers in just a few years.
In the paper, published in Nature Communications, the researchers described using the genome-editor CRISPR to alter a protein in chicken cells that flu hijacks to make copies of itself. If the virus can’t take over that protein, the idea goes, it can’t establish an infection.
Scientists found that in the ANP32A gene-edited birds, the virus had adapted to enlist the support of two related proteins—ANP32B and ANP32E—to replicate.
To prevent the emergence of escape viruses—viruses that adapt to evade the gene edit and cause infection—the research team next targeted additional sections of DNA responsible for producing all three proteins—ANP32A, ANP32B and ANP32E—inside lab-grown chicken cells.
In cell cultures in the lab, growth of the virus was successfully blocked in cells with the three gene edits.
The next step will be to try to develop chickens with edits to all three genes. No birds have been produced yet.
Unexpectedly, this virus also replicated in chicken embryos edited to remove the entire ANP32A gene and instead co-opted alternative ANP32 protein family members, chicken ANP32B and ANP32E. Additional genome editing for removal of ANP32B and ANP32E eliminated all viral growth in chicken cells. Our data illustrate a first proof of concept step to generate IAV-resistant chickens and show that multiple genetic modifications will be required to curtail viral escape.
Eliminating all three ANP32 genes from chicken cells grown in a lab dish stopped the virus from replicating at all. But because having at least some ANP32 proteins may be important for developing chick brains, bones and hearts, that strategy might cause problems for live chickens.
If this was a disease that only infected chickens, yes, then the resistance we created would be better than what we would get with a vaccine. But because this is a zoonotic disease, and can be spread potentially to humans, we really need to aim for complete resistance. Not resilience, resistance, so the virus cannot grow in the chickens.
I think the world is changing. Countries are bringing in new legislation to bring in regulations that will look at the safety of gene-edited animals for food, and within a few years, there will be the regulations in place. And the biology will follow along behind.
