ANP
The new bird flu season is just around the corner, while the previous outbreak is still ongoing. More than 626,000 animals were killed this month alone. Yesterday, a poultry farm in Drenthe experienced the largest culling since the first outbreak of the current season, almost a year ago.
The bird flu season has never lasted this long and the number of outbreaks continues to increase, which worries biologists and virologists. They fear that the virus may never go away. Five questions and answers about bird flu.
1. What’s going on?
In the Netherlands we have been dealing with bird flu for almost twenty years, but never before did the virus also occur in the summer. “The outbreak since last autumn is the largest ever in Europe,” says virologist Thijs Kuiken of Erasmus MC, who specializes in bird flu. “More than 4 million birds have already been killed in the Netherlands.” Since October last year, the poultry has been culled on about 120 farms.
Bird flu naturally occurs in wild birds, but they can be infected without getting sick. In poultry, the virus can mutate into a pathogenic variant. If an infected feather or a small amount of contaminated manure ends up in a barn, the disease can spread very quickly and thousands of animals can die. Because of this risk of contamination, all poultry on an infected farm is culled.
2. Why does bird flu last longer than usual?
“The special thing about the current bird flu is that the pathogenic virus from poultry has been transferred to wild birds, so that they spread it over a great distance,” says Kuiken. Normally, migratory birds bring the bird flu virus to the Netherlands in October. In April they leave for the east again, so that the virus disappears again. Wild birds in the Netherlands are now also infected that stay here in the summer.
As a result, we had to deal with outbreaks last summer. “We let the virus slip from our fingers when it moved from poultry to wild birds,” says the virologist. “The pathogenic variant does not originally occur in nature, which was created by intensive poultry farming. And you cannot control wild birds.”
3. What can we do about bird flu?
A first step is the obligation to keep poultry in cages to prevent rapid spread. In the short term, measures such as a vaccine and an annual check in stables can provide a solution, says Kuiken. Vaccines are not used in Europe and the United States. This is already happening in South America and Asia.
The poultry sector is divided over the use of vaccines. A disadvantage for companies is that products from vaccinated poultry may not be exported abroad according to European rules. At least two thirds of Dutch poultry goes abroad.
In the long term, companies should not be located in areas with many waterfowl, says a zoonoses expert group. “The companies are also too close to each other, such as in the Gelderse Vallei,” says Kuiken, who is part of the expert group. “That makes it easy to jump over.”
Poultry density in the Netherlands is high and therefore the risk of outbreaks is high, says Kuiken. More than 100 million chickens and other poultry are kept in the Netherlands.
4. How dangerous is bird flu for other animals and people?
In addition to wild birds and poultry, other animal species can also become infected. This year, for example, infected foxes and otters were found in the Netherlands. There are also known cases of seals abroad, which can also transmit the virus to each other.
The virus is not harmless to humans. In the Netherlands, a veterinarian became infected and died during the outbreak in 2003. In China, many more people have died of a variant of bird flu in the past. For the time being, we do not have to worry much with the current virus, says the virologist. “But if the virus mutates and people can infect each other, then the risk becomes very high.”
5. Will we ever get rid of it?
As long as there is intensive poultry farming, we will not get rid of bird flu, says Kuiken. “Only if we completely adapt the poultry industry system can we banish it in the long run”. In all likelihood, we will have to deal with infections again in the summer next year. “The sickening virus has established itself here and for now it will remain here.”