Avian Influenza: Myths and Realities

The commercial poultry industry is concerned about the continued spread of Avian Influenza (AI) and is closely watching as this disease is found in more countries around the world. Almost daily we receive reports that there are more outbreaks here or there in different media. We see these reports in digital newspapers, television, radio, and this time we are bombarded with more ads on WhatsApp, Twitter, Facebook, TikTok, Instagram, Telegram, etc. In many cases, we do not know the source of the information and the headlines are often alarming and frightening to consumers who do not understand the disease and the structure of the poultry industry. Normally, when there is another outbreak, it starts with a simple news report. However, as the report circulates, fear builds as rumors and misinformation are spread. Like a snowball rolling down a hill and growing in size until it falls like an avalanche. This forces us to make decisions in a panic and without much thought, that in the long term are not in favor of either the poultry farmer or the consumer. The objective of this paper is to separate the myths and realities of AI and offer some common-sense perspective.

Realities:

Avian influenza has been circulating among migratory and wild birds for hundreds of thousands of years.
Many millions of birds migrate from north to south and vice versa when the seasons change. Each year, these migrating birds may be replicating and shedding several serotypes of AI on the different migratory bird routes.
In the current outbreak, the incidence of infection and spread of the virus has been higher than what we have commonly found in prior years. The predominant serotype is H5N1 and is highly pathogenic when spread to commercial poultry. This AI has also been found at higher levels on migratory routes reaching regions in South and Central America. We also see this H5N1 AI virus in migratory birds in different flyways around the world.
In a normal year, more than 30% of migratory birds carry and excrete the virus through their feces and nasal secretions as they cross the Canadian border into the USA. These feces and nasal secretions can contaminate surface water, wild birds, small backyard flocks and the entire area around poultry farms. It should be noted that over time as birds continue to migrate, the degree of infection naturally decreases as the infected birds develop immunity and become more resistance. For example, when birds arrive in Florida, the level of infection and excretion can drop to 4% and when they arrive in Central America the degree of infection is even lower.
Transmission peaks are highest in the months of February to May. In spring, migratory bird chicks hatch, and many of these newborn chicks are susceptible and can serve to replicate and cycle the virus.
Normally, migratory birds cycle AI viruses of low pathogenicity to poultry. However, sometimes as in 2015 and 2022-2023, they are affected with AI viruses that are highly pathogenic to poultry. In most cases, the AI viruses of migratory birds that can infect our commercial poultry are of low pathogenicity. However, H5 and H7 strains could mutate into highly pathogenic strains after they pass into poultry and cycle among flocks.
Over time, these AI viruses circulating in migratory birds decrease in incidence since much of the bird population acquires immunity, and then new AI strains replace them, and the cycle continues.

Reasons for spreading:

People:

On analysis of the current H5N1 AI situation in the USA, we have seen that 85% of outbreaks occur by contact with infected wild birds and their infectious secretions, and then are mechanically taken to the poultry farm. For example, a worker steps on the feces of migratory birds before entering a farm, or surface water contaminated by feces of migratory birds that is not chlorinated, or wild birds that can enter the poultry house through doors and openings in meshes, curtains, broken ceilings, etc. Only 15% was spread from a contaminated farm to another farm by people, equipment, or vehicles. This pattern shows that biosecurity has been very good and that once the incidence of infection in the wild bird population declines, the disease in commercial poultry should also fizzle out.

In the 2015 outbreaks of AI in the USA, 85% of the spread was from farm to farm. The poultry industry learned from these outbreaks that occurred in 2015. Thus, in the current outbreak, the need to quickly euthanized sick birds was implemented. A dead bird does not spread the virus. We have been able to make great progress.
While it has been reported in the European Union, in the current outbreak, that 85% of the breaks occur by spread of the virus from one farm to another. Thus, biosecurity is not working, in part due to chickens having outside access where there are many more opportunities for birds to have contact with migratory birds. Regulations for more ‘humane’ production methods have led to more risk for disease and catastrophic losses!

Manure:

The trucks that transport the manure from poultry houses are going to contaminate the roads. If the manure is dumped near the farms, it is going to increase the possibility of spreading AI and many other diseases to commercial poultry close by. Wild animals that have contact with the manure may spread the disease back to poultry farms.

Backyard and organic birds:

Do regulatory agencies have any monitoring systems for small flocks? These small flocks are often permitted access to the outdoors and thus are more likely to be infected and maintain the cycle of disease. Anyone can become infected by having contact with these birds and can even walk on top of feces and carry contamination from one farm to another. These farms should confine their birds during the Avian Influenza crisis and have adequate footbaths, and if possible, bathrooms for changing clothes or showering. Small farms with access to the outside are a danger to the entire poultry industry that is critical to supplying chickens and eggs for human consumption.

Indemnity:

The government must have funds to compensate farmers if there is an outbreak. There should be an incentive to report a disease outbreak as soon as possible, and a fine if the outbreak is not reported. Identifying the infected batch and euthanizing as early as possible is key to eradicating disease in commercial birds. If urgent action is not taken, the disease often becomes endemic.

Live poultry market:

This is a major contributing factor to a poultry disease becoming endemic. In some countries, the government has eliminated live bird markets and have seen AI outbreaks often quickly disappears. While in other Asian countries, only when there is an outbreak does the government temporarily suspend all live markets until the outbreak is eradicated.

Vaccines:

In countries where AI vaccines have been used without regulations, avian influenza commonly becomes endemic. The vaccine can reduce losses and thus there is little desire to commit to eradication. These countries with endemic AI (and Newcastle disease) do not prosper because they have infected birds. This results in reduced broiler performance and limited ability for developing an export market.

To vaccinate or not to vaccinate!

There is much conversation in the U.S. and other countries concerning use of vaccines against the current global H5N1 AI outbreak. Most likely, as we have seen in previous outbreaks, discussions among government experts and research centers will continue until the disease fizzles out and is soon forgotten. The discussion will be reignited with the next outbreak. The question is whether vaccines can help eradicate AI. The answer is yes, but only if they use them correctly. Unfortunately, this is rarely done well and leads to an endemic infection that can destroy the future of a country’s poultry industry.

Rule #1 is to use vaccines correctly with a well-established protocol, among them we can mention a few:

Only use approved and updated vaccines containing current and homologous AI strains. Examine vaccinated flocks regularly.
Immediately depopulate any vaccinated flocks that are infected. The vaccine should be used only for the purpose of reducing excretion. So, if a vaccinated flock becomes infected, it should be euthanized immediately. Sick birds should be buried, burned, or composted and the farm should be cleaned and disinfected before reintroducing a new flock. The reason that vaccines usually fail, and the disease becomes endemic is that farmers using vaccines and have an infected flock have little incentive to report the breaks and euthanize the flock. They sell the surviving birds, often in live markets where disease spreads or surviving chickens are processed and the catching crew, transport vehicles and processing plant all become contaminated. Some farmers will try to keep the birds alive for sale, because they do not have the financial resources to depopulate the entire lot. This extended period of vaccine excretion increases the ability of the vaccine to be transmitted to other sites. Infected live birds are excreting millions and millions of viruses and spread to all the integration, region, and country.

Key to success:

Do everything possible under your control so that there are no outbreaks (true biosecurity). If there is an outbreak report immediately so increased biosecurity is implemented in the area.
Euthanize and depopulate all chickens on the infected site in less than 24 hours and establish a quarantine zone.
Have an action plan for feed delivery, reduce farm visits to those essential, and have disposable clothing stocked and showers ready to use.

Goal:

The goal is prevention.

In life, all the decisions we make daily have certain degrees of risk. However, making decisions based on adequate and reliable data has less risk. If an AI vaccine is used and employees get a false sense of security and relax the biosecurity rules, the chance of disease introduction increases, and the disease can become endemic.
If there is an outbreak, you should have a solid plan for rapid eradication and culling. Remember that rapid identification, communication, and euthanasia of the flock are needed in less than 24 hours.
Dead birds can be left in the houses until they can be properly disposed or composted on the same farm.
Always remember that the virus in dead birds does not replicate and is not excreted in feces or nasal secretions. This was an important lesson learned from the previous outbreak In 2015 in the USA.
Making mistakes in dealing with Avian Influenza such as using vaccines incorrectly will result in the disease becoming endemic for decades as we have seen in other countries.
The big question in each country is if the whole country has the will and resources to eradicate AI and live through this short but difficult economic crisis.
The other option is to use methods that historically lead the virus to become endemic and lose prospects for a safer and more prosperous future for your poultry industry.

Avian Influenza: Myths and Realities

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