What you need to know about the H5N1 virus Bird flu arrives in Switzerland - first case discovered

Switzerland has its first bird flu case of the season: a swan died in the Reuss delta in the canton of Uri. The authorities reacted immediately. Here you will find the most important questions and answers about bird flu.

A swan that died in the Reuss delta was found to be infected with the H5N1 bird flu virus on Monday. In consultation with the Federal Food Safety and Veterinary Office (FSVO), the canton of Uri immediately set up a control and monitoring area in the vicinity of where the virus was found.

Poultry farmers there must adhere to requirements to ensure that the bird flu virus cannot enter their farms and prevent their flocks from coming into contact with wild birds. This is because the situation is dynamic throughout Europe and is being monitored by the FSVO. You can find the most important questions and answers about bird flu here.

"The events throughout Europe confirm a high infection dynamic in Europe", says the FSVO on request. According to media spokeswoman Tiziana Boebner-Lombardo, "the risk of HPAI entering and spreading in Switzerland has therefore risen sharply". The FSVO provides an up-to-date overview of the situation on its website.

"The population is advised not to touch sick or dead animals", adds the Federal Office of Public Health. "People who come into contact with potentially infected poultry or captive birds on a professional or regular basis should protect themselves appropriately."

"Preventive measures are very important throughout Switzerland," emphasizes FSVO spokeswoman Boebner-Lombardo. For example, dead wild birds are systematically examined in order to detect a possible bird flu circulation in Switzerland at an early stage.

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The FSVO points out that contact between domestic poultry and wild birds should be prevented. Anyone keeping poultry should ensure that biosecurity measures are applied: shoes and clothing suitable for the poultry house, hand hygiene. Feeding and watering should take place in an area that is not accessible to wild birds. Animal keepers who notice suspicious symptoms must report them to a vet immediately.

Private individuals who come across dead or sick wild birds should not touch them. "They are called upon to report them to the responsible wildlife authority or veterinary office for recovery and examination," the FSVO asks.

H5N1 avian influenza is currently widespread in wild birds around the world. All bird species are affected. However, according to the BLV, waterfowl, such as ducks and geese, rarely fall ill, and when they do, it is less severe. Farm poultry such as chickens and turkeys usually show clear signs of illness when infected.

Many wild mammals are also infected. In Vietnam, tigers and lions in zoos died of bird flu. According to the FSVO, bird flu affects badgers, dolphins, sea lions, foxes, otters, cats and grizzly bears.

The virus has also recently led to outbreaks in poultry farms and dairy farms in the USA. However, the extent of the outbreak is largely unclear due to a lack of data.

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Researchers fear that the virus can adapt better to mammals if it circulates widely in them. A study published in August showed transmission from mammal to mammal, even between different animal species, such as from cows to cats.

Mutations of the virus that would lead to improved transmissibility of H5N1 to humans have not yet been discovered.

"No cases of avian influenza have been detected in wild mammals in Switzerland," says the Federal Food Safety and Veterinary Office.

Researchers fear that the virus can adapt better to mammals if it circulates widely in them. A study published in August showed transmission from mammal to mammal, including between animal species, for example from cows to cats. Mutations of the virus that would lead to improved transmissibility of H5N1 to humans have not yet been discovered.

"To date, there has been no confirmed case of H5N1 infection in humans in Switzerland," writes the Federal Office of Public Health (FOPH) in response to an inquiry from blue News. However, media spokesman Simon Ming points out that an infection with the bird flu virus must be reported. "As soon as there are indications of exposure, such as close contact with sick poultry, those affected can be tested for the bird flu virus."

"The probability of infection with the H5N1 avian influenza virus subtype is currently very low for the general population in Switzerland," says the FOPH. For occupational groups that may come into contact with sick birds or other animals, the probability of an avian flu infection is estimated to be very low to moderate. This depends on the spread of the disease among animals.

The H5N1 avian flu virus has increasingly spread to mammals in recent months, including dairy cattle in the USA. Human infections have also been detected there. The infected people worked on poultry farms and also contracted the virus during milking.

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Numerous human infections with the H5N1 bird flu virus are apparently not being detected. Tests have revealed an infection rate of seven percent, reported the US health authority CDC.

In the USA, a total of 46 cases of bird flu have been detected in humans since April 2024, mainly among employees of dairy and poultry farms. They had mild cases and only some showed any symptoms at all.

According to the website of the Federal Office of Public Health, flu-like symptoms usually appear two to 14 days after contact with an infected animal. The symptoms can vary in severity. There is currently no vaccine approved for humans against bird flu. However, the development of a vaccine is being monitored by the FOPH.

Human-to-human transmission has not yet been proven.

Animals become infected via droplet infection or by inhaling dust containing the pathogen. Young animals are more at risk than older ones.

According to current research, H5N1 is mainly transmitted between cows via milk.

With agency material.