Avian influenza

-Automatic translation

Four types of influenza viruses exist: A, B, C, and D. Three of them can cause disease in humans: A (causing pandemics and seasonal epidemics), B (causing seasonal epidemics), and C (resulting in minor illness). Influenza A virus can infect various animals and is named after the relevant host, such as avian, swine, equine or dog influenza viruses.

Influenza A viruses are classified into subtypes based on their surface antigens H (hemagglutinin) and N (neuraminidase). For example, the 2009 swine flu was an influenza A(H1N1) virus with type 1 hemagglutinin and type 1 neuraminidase.

Influenza A viruses are prone to mutation and reassortment, primarily when different viruses infect the same individual simultaneously. This poses a risk for the emergence of new influenza virus subtypes, mainly if a bird flu virus infects individuals also infected with human flu virus. The same threat exists when more than one type of influenza virus infects minks, pigs, or other mammals. This ability of influenza A to reassort and develop new subtypes to which people have little immunity can lead to pandemics, as seen with the Spanish flu in 1918 and swine flu in 2009.

-Automatic translation

Ducks are natural hosts of influenza A, with birds presumed to be the origin of most influenza virus types. Avian influenza is usually mild in wild birds but can be severe in poultry and affects various mammals, including minks, foxes, pigs, seals, whales, dogs, and cats.

Avian influenza A viruses are classified as mild or severe (low or highly pathogenic avian influenza; LPAI or HPAI), depending on their impact on birds. This classification doesn't apply to the severity of disease in people. So far, only subtypes H5 and H7 have caused severe avian influenza. Severe avian influenza causes significant damage to wild bird populations, can spread widely with migratory birds, and damages poultry farms if they are affected.

Global outbreaks of avian influenza A have occurred repeatedly. Some influenza types have spread considerably among bird populations and even caused local cluster infections in humans. However, these types have not adapted to transmit between humans and cause epidemics among people.

Since 2021, an outbreak of avian influenza A of the H5N1 type has spread significantly in Europe and globally. Millions of birds, mainly wild waterfowl, seabirds, and poultry, have been infected in Europe. Infections have also been detected in mammals, primarily wild predators in close contact with wild birds and on fur farms. In Iceland, an H5N1 strain was first detected in wild birds in April 2022 and domestic chickens in one location.

The H5N1 type has infrequently been detected in people, and the risk of infection to the European public from the current H5N1 strain is considered low. No cases of H5N1 infections in humans have been confirmed in EU/EEA countries. Serious illness and even deaths have occurred in people in other parts of the world, especially in Asia and South America, but most of the individuals seem to have been in prolonged or close contact with sick birds associated with keeping birds at home.

-Automatic translation

Bird droppings (faeces) are the primary transmission route among birds, as infected birds excrete large amounts of the virus in their droppings. Airborne transmission is also possible through coughing and sneezing.

Human cases of severe avian influenza have resulted from close contact with infected poultry or their body fluids, contaminated surfaces, or environments where infected birds dwell. Dust from feathers or the environment of sick birds, which swirls around in a closed space during activities like flapping of wings, skinning, high-pressure washing, or sweeping, can increase the likelihood of transmission to people.

There is an increased risk of infection from infected birds to people during the following activities:

• Close contact with poultry, products and waste, e.g. work on poultry farms.

• Handling of bird carcasses, especially during skinning.

• Poultry disposal and destruction of carcasses and waste.

• Cleaning and disinfection of contaminated areas.

• Sampling from birds and contaminated environments.

• Veterinary examination.

• Analysis of the virus in a laboratory.

There is no risk of infection from well-cooked eggs or meat, as the virus is killed by heat (three hours at 56°C, 30 minutes at 60°C, and one minute at 70°C). Standard washing eliminates the virus on clothing.

-Automatic translation

Symptoms prompting testing of individuals under observation for bird flu include fever, red eyes, cough, cold, muscle- or bone pain, diarrhoea, pneumonia, breathing difficulties, and neurological symptoms (headache, seizures, altered consciousness).

Remaining vigilant and adhering to preventive measures is vital for effectively managing avian influenza risks.

- Automatic translation -

Basic infection prevention precautions

A fundamental caution must be exercised in all work in which people are in contact with animals, irrespective of whether or not a communicable disease is suspected. Pollution is hereafter referred to as the body fluids of animals or people.

• It is the employer's responsibility to ensure that staff receive the necessary instruction and training to perform their duties in such a way that there is no danger (cf. Article 14 of Law No. 46/1980).

• Those who in their work may come into contact with infected birds, their products, or waste or pollution in the environment must be educated about the symptoms and ways of transmission of bird flu and how to prevent infection.

• Special emphasis is placed on the importance of careful hand hygiene (with hand washing and hand sanitizer) after contact with birds (infected and uninfected), after contact with contaminated areas, and after using gloves.

• Proper hand washing means washing all areas of both hands with soap and water for 30 seconds, followed by the use of disposable wipes. If there is no visible dirt on the skin of the hands, an approved disinfectant can be used, e.g. hand sanitizer (70% - 85% ethanol).

Vaccination during annual influenza epidemics

• The routine annual influenza vaccination for people can reduce the chance of the development of new/harmful influenza A strains when an avian influenza virus infects individuals who are simultaneously infected with human influenza.

• Annual influenza vaccination is especially important for those individuals who are at increased risk of exposure to avian influenza due to contact with birds.

• Conventional vaccination against seasonal influenza does not protect against infection with avian influenza, and therefore recommendations and rules for infection prevention must still be followed.

The following groups at higher risk of exposure to AI shall be offered vaccination against seasonal influenza (priority groups annex)

• Employees of poultry farms, pig farms, and fur farms.

• Veterinarians who handle the above farms or related tasks.

• Personnel involved in the transport or killing of poultry, pigs, and fur animals.

• Personnel involved in the disposal or dissection of sick animals where there is a risk of infection.

• Staff at petting zoos where there are birds, pigs, seals, or fur animals.

• Icelandic Food and Veterinary Authority

• European Food Safety Authority (EFSA)

• Instituto Zooprofilattico Sperimentale delle Venezie (IZSVe)

• World Organisation for Animal Health (WOAH) 

• European Commission - Avian influenza