2023-10-14 12:22:05
British scientists used genome editing – i.e. the targeted modification of genetic information using so-called genetic scissors – to replace two amino acids in the host protein ANP32A. This protein is necessary for the avian influenza virus to multiply in chickens. The researchers found that when the viral load was low, nine out of ten genetically modified chickens did not become infected, but as the viral load increased, resistance decreased.
This is a very interesting approach that deserves to be pursued further, says Professor Timm Harder, laboratory manager at the Friedrich Loeffler Institute. He engaged in the study.
Avian influenza infection is a death sentence for chickens
Currently, avian influenza infection is a death sentence for chickens. If an animal contracts bird flu, also known as avian influenza, the entire population must be killed. The goal is to prevent further spread and to spare the animals suffering, explains Dr. Franz Kronthaler from the Bavarian State Office for Health and Food Safety (LGL): “But you also have to keep in mind that avian influenza is a very serious disease for poultry. This means that killing the animals quickly eliminates the suffering caused by the disease “The disease leads to death in the vast majority of cases.”
Such a case occurred in May in the Regensburg district, for example. After an outbreak of bird flu there, 60,000 chickens had to be culled.
Prevention measures: operational hygiene and avoiding contact
To prevent things from getting that far, chicken farmers pay attention to good operational hygiene. For example, you only wear certain work clothes and shoes in the stable so that no viruses are introduced from outside through clothing. The virus is usually transmitted via the feces of wild birds, dust or droplet infection.
Farmers also try to avoid contact between poultry and wild birds by building boundaries. Many chickens stay in the coop all their lives and don’t have any space to run. Organic or free-range chickens, on the other hand, can go outside. However, if a wild bird infected with bird flu is discovered, the district office of the affected district imposes a requirement for poultry to be kept in stables for a certain period of time.
This means: Chickens – including those from hobby keepers – who are otherwise allowed to scratch outside are in “lockdown”. Then it is even more important that the owner provides activities in the stable so that the animals do not peck at each other out of boredom, explains Dr. Franz Kronthaler from LGL. In his opinion, chicken farmers should think regarding possible coop requirements beforehand and design the coop accordingly.
In the Landshut and Dingolfing-Landau districts, a four-week stable requirement was imposed in the spring following around 700 dead black-headed gulls were found around Lake Wörthersee near Wörth an der Isar in the Landshut district at the end of April. An investigation found that the animals had died of avian influenza.
Complete resistance would probably have fatal consequences
Compulsory stables, illness, suffering, culling – chickens might be spared all of this if they were resistant to avian influenza. But there is a catch in the new British study: complete resistance in chickens might theoretically be achieved if not just one, but all three genes of the ANP32 gene family were changed. But that would probably be fatal for a chicken. This was shown by experiments in cell cultures.
Prof. Timm Harder from the Friedrich Loeffler Institute sees further hurdles: virus mutations might circumvent the resistance mechanism. And: For him, whether the meat of such genetically modified chickens will be accepted and bought by consumers remains in the stars.
Completely bird flu-resistant, genetically modified chickens will probably not be available in the near future. Rather, chicken farmers are hoping for a vaccination once morest avian influenza that can be administered to the animals through water, explains Dr. Franz Kronthaler from LGL. No vaccine once morest avian influenza has yet been approved in the EU, but many companies are researching it.
Bird flu is also dangerous for humans – no cases are known in Germany
The bird flu viruses can also pass to humans. According to the Robert Koch Institute, there is currently no known transmission of bird flu viruses from poultry to humans in Germany.
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