In the booming populations of East and Southeast Asia, huge quantities of chicken meat are eaten every day. Chicken is one of their most important sources of protein. But chickens and also ducks are often raised in small areas, under very unhealthy conditions: an ideal breeding ground for viruses, like the avian influenza virus. In 2003 this virus, commonly known as
bird flu captured the world’s attention: it not only kills poultry but also wild
animals, in particular, waterbirds. It can even kill humans. However, despite often overblown media reports, since 2003, one of the most lethal strains of avian influenza virus,called H5N1, killed 400 people only. In comparison, HIV, the virus that causes
AIDS, during the same period of time killed more than 24 million people. In the case of bird flu, the most common victims are actually birds,
not humans What do we know about avian influenza,
and how can we control it? Every year, millions of wild birds
undertake impressive journeys. They travel tens of thousands of kilometres between their breeding areas in the north and wintering grounds in the south.
They need to migrate in order to survive. Across the globe, there are several bird migratory routes, called flyways.
One of the most important is the East-Asian Australasian flyway that stretches
across 22 countries, and is used by 70 million birds of over 300 species. During the long migration, birds face
many challenges. One is the loss of critical sites and
habitats that serve as vital “stepping stones”. Another is battling diseases such as
avian influenza. Scientists from all around the world are trying to understand how migratory birds can adapt to the rapidly changing environment on their journey, and how they can cope with diseases. Avian influenza viruses – they’ve been around for a long, long time and notably in waterbirds because both the water birds and the virus they thrive in water. There are two different forms of the virus: a low pathogenic form that has always been around and a high pathogenic form that makes birds really sick. And in nearly all cases we have been able to track that down to something happening in poultry. So what’s the story here? Wild waterbirds such as ducks, geese, swans and shorebirds can carry the harmless, low pathogenic form of the avian influenza virus. This virus can spread from one bird to another without making the bird sick. But if the virus turns up in a poultry farm where many chickens and ducks live in unhygienic conditions and small areas, the virus can turn into a harmful, high pathogenic form. This harmful virus can spread rapidly among poultry, and most of the infected chickens or ducks die shortly afterwards. However, some of them don’t show any symptoms of the disease and continue to spread the virus for a longer period. Finally, the
evolved harmful virus can get back to the wild waterbirds and spread among
them. While some studies claim that some wild birds could recover from the
infection, the more common outcome is sickness and eventual death. You can never rule out that a low-pathogenic form can evolve to a high pathogenic forms in wild birds. But there is a very little evidence for that. It’s been very common in East-Asia to blame migratory waterbirds for avian influenza.
But in fact, migratory birds are more the victim than the culprit. For example, in 2005 in Qinghai Lake in China, over 6000 wild birds died of an avian
influenza outbreak. Researchers found that the source of the outbreak was domestic poultry held captive in the vicinity. Scientists agree that wild waterbirds, including migratory species, naturally carry harmless forms of the virus and that some species are susceptible to harmful forms. But the real risk factor in the spreading of the avian influenza virus is contact between wild and domestic birds. Nowadays the risk is higher as the number of poultry is increasing, particularly those in open range areas. At the same time, there are less natural habitats for wild birds, thus domestic and wild birds are forced to share the same wetlands. Migratory waterbirds often concentrate during the non-breeding season in a small area, so you can find 80% of the world’s population in one reservoir which is the case of the Baikal Teal. In the early 1990’s, this number was over a million ducks, however in recent years these numbers have dropped to 300-400 thousand. So
if there was an outbreak, if somehow a virus gets among these birds, it can
destroy most of the birds and can lead to the extinction of the whole species. We often hear in the media that wild migratory birds spread the bird flu. Thus people mistakenly believe that wild birds introduce the harmful form of the virus into their farms, which can then kill their poultry, and even themselves. This fear sometimes leads them to chase the birds, and even to kill them. They go and chase the ducks and the geese away, causing disturbance to the birds and also if these birds have some infection already among them, they chase them to other lakes and other parts of the country, which makes the outbreak much worse. Also sometimes the reaction of the local governments is spraying disinfectant into natural water bodies and wetlands which
causes a lot of damage to waterways and is completely useless against the influenza virus. Also it’s highly illegal. The high pathogenic avian influenza virus is a major problem. And the solution is not chasing or
killing the wild birds, nor is it disinfecting or poisoning
natural wetlands. These actions are useless against high pathogenic avian influenza outbreaks. So what can we do? The solution is to improve bio-security. Bio-security means protecting poultry by preventing diseases like avian influenza virus from entering the farm. It also means protecting poultry farms and wild birds in
the surrounding wetlands, by stopping the disease from leaving affected farms. Bio-security does not only benefit
farmers by keeping their poultry healthy but helps to sustain the environment, and keep wildlife and humans free of disease. Poultry farmers still remember the times before applying bio-security protocols. There are a few simple steps we can take to improve bio- security: The poultry farmer should disinfect or change shoes when entering the farm. The farm should be kept free of droppings that could spread the virus. Dead poultry should be removed and incinerated or buried deep in the ground to avoid the transmission of the virus to healthy birds. The water and air entering into the poultry farm should be filtered. Water contaminated by infected poultry must not have access to natural wetlands, unless treated properly. The poultry farmer should change clothes when entering and leaving the farm. Farm clothes and tools should be regularly disinfected. Similarly, the equipment used to transport poultry products should also be cleaned to avoid the transmission of the virus to other poultry farms. Farmers have to make sure that wildlife
and poultry are strictly separated. Poultry infections should be immediately reported to authorities, to take prompt action. That is a very simple and highly doable solution to the problem that would benefit our economies and would benefit wildlife. Finally, these bio-security measures protect wild birds, including endangered migratory species, from becoming infected and dying unnecessarily. Let’s work together to combat the threat
of avian influenza virus, so that our migratory birds may continue their extraordinary journeys.