Avian flu (avian influenza, also known as bird flu) is a contagious disease primarily found in birds. Sometimes the virus also infects mammals. Avian flu is almost never found in humans. Various influenza viruses that can cause avian flu have been observed worldwide. 

Avian flu, migratory birds and variants 

Avian flu affects the respiratory system (nose, mouth and airways), digestive system and/or nervous system. The disease occurs in poultry raised on farms (chickens, ducks and turkeys) and nearly all species of birds found in the wild, including ducks, doves, pigeons, geese, seagulls and storks. Birds of prey and other predators can also contract the virus by eating birds that fell ill or died of avian flu. 

The Netherlands is a major waystation for migratory birds. Almost all birds that migrate pass through the Netherlands, often touching down and sometimes staying for extended periods. This applies to hundreds of millions of birds every year. Migratory birds can carry the virus, bringing new variants of avian flu with them to the Netherlands. 

High and low pathogenicity 

Highly pathogenic avian influenza (HPAI) is deadly to birds. Since poultry farms usually keep the birds close together, outbreaks at such locations affect many birds at once. Wild birds can also contract the highly pathogenic variants.  Low pathogenic avian influenza (LPAI) causes minimal or no symptoms in birds. Read more about these different types of avian flu (in Dutch) on the website of the Netherlands Food and Consumer Product Safety Authority (NVWA)

Avian flu in birds 

Birds that contract a highly pathogenic variant become ill very soon after infection. The first symptoms often appear within a few hours after exposure, or up to 3 days later. In these cases, the disease is fatal. The first symptoms are: 

  • lethargy 
  • no longer making sounds 

 The birds may also develop other symptoms, such as: 

  • breathing problems 
  • diarrhoea 
  • closed and runny eyes 
  • unusual head movements, often twisting
  • sudden death

Field tests with poultry vaccination

In autumn 2023, the Ministry of Agriculture, Nature and Food Quality (LNV) launched a field test for vaccinating poultry. 1800 newly hatched chicks were vaccinated against highly pathogenic H5N1 avian influenza. The field test will continue until the end of 2025. 

Read more about avian flu (in Dutch) on the website of the Netherlands Food and Consumer Product Safety Authority (NVWA), or consult the international information provided by the World Health Organization. 

Avian flu in humans 

In rare cases, avian influenza viruses can be transmitted from animals to humans. This only happens after extended close contact between humans and infected animals (birds or mammals). It is not very likely that humans will contract avian flu, based on the virus variants that are currently circulating. If a person is infected, they will often develop minimal symptoms, or none at all. If they do become ill, their symptoms are usually similar to ‘ordinary’ flu: fever, headache, muscle aches and coughing. People with avian flu sometimes also develop an eye infection. It is very unlikely that someone with avian flu will infect other people.  

Avian flu in humans does not always cause a mild course of illness. Some types of avian influenza, especially in Asia, can sometimes make people very ill. In these cases, they cause severe pneumonia or shortness of breath.  

Preventing avian flu 

Do not touch dead birds in the wild

If you see a dead bird out in the wild, do not touch it! Report the dead bird to the Dutch Wildlife Health Centre (DWHC) or SOVON.

Dead bird in the garden or on the balcony?  

Is there a dead bird in your garden or on your balcony? Then you can report the dead bird to the Dutch Wildlife Health Centre (DWHC) or SOVON. If you dispose of the bird yourself, make sure to use disposable gloves or a plastic bag to lift the bird and throw it away. Place the bird inside a closed bag before tossing into the trash. Also throw the gloves away after use, and scrub your hands with soap and water. More information on this topic is available on the DWHC website.

If you think you might have become ill from the avian influenza virus, after touching a sick bird or other animal, contact your GP. Mention that you were in contact with a sick animal. 

How common is avian flu?  

Until winter 2021, there were avian flu outbreaks every few years at poultry farms in the Netherlands, which occurred in the winter months. During the winter months in 2021, a high number of farms reported infections, breaking from the previous trend. Since then, there have been avian flu outbreaks among poultry all year round. There has been a striking increase in avian flu among waterfowl in the Netherlands. Birds that nest in colonies have been hit hardest. Avian flu has become a pandemic among these birds, affecting very high numbers of waterfowl worldwide.  

See the website of the Netherlands Food and Consumer Product Safety Authority (NVWA) for details on the current situation (in Dutch). 

Risks of avian flu for cats and dogs 

Sometimes the avian influenza virus can be transmitted to mammals living in the wild, such as foxes, ferrets and seals, and to household pets like cats and dogs. They are usually exposed to the virus by eating an infected animal (live or dead) or picking it up in their mouth. There have been no confirmed cases of transmission from cat or dog to humans. Do you suspect that your cat or dog has become ill after contact with a dead or potentially ill bird? Contact your vet. Keep dogs leashed around dead birds, or if dead birds have been found in your area.