Avian influenza

Background information

Avian influenza is a disease of birds and is caused by influenza A viruses. There are two forms of the disease in birds: low pathogenic avian influenza (LPAI) and highly pathogenic avian influenza (HPAI). It is important to note that avian influenza is not pandemic influenza, which is a human influenza virus.

Organism

Influenza A viruses

Incidence and Transmission

Wild birds act as a reservoir for avian influenza. Transmission to humans is rare and there have been very few confirmed human cases in the UK.

Spread occurs via direct contact with the secretions of infected birds, especially faeces and saliva or via contact with contaminated bedding, clothing and equipment. There is no risk of infection from consuming eggs or chicken products.

Spread is facilitated by the movement of wild bird flocks, domestic birds, people and vehicles from contaminated farms.

As yet there has been no evidence of person to person spread, but there are fears that the virus could change (via genetic reassortment) and acquire this characteristic.

Person to person spread is rare, but there are fears that the virus could change and sustained human transmission might occur.

Occupations and processes where avian influenza presents a risk

Occupational exposure to avian influenza may occur in those who:

are in close contact with infected birds or humans;
work with materials or products from infected birds; or
are in contact with waste products from infected birds.

Occupations where there may be a risk of occupationally acquired avian influenza include:

poultry farmers;
zookeepers;
bird keepers;
pet shop workers;
veterinary surgeons;
poultry processing plant workers;
animal health workers in border control; and
healthcare workers – caring for infected patients;

Clinical Information

The incubation period is generally 2–8 days, but can be longer. Human illness is varied and can range from, in most cases, conjunctivitis or mild flu-like symptoms to severe respiratory illness that may be fatal.

Anyone who has been in contact with infected birds or their faeces and who develops a flu-like illness should seek medical attention. Antiviral treatments are available, which if given at an early stage of the disease are likely to be effective in reducing symptoms and the risk of severe disease.

Control

The following control measures reduce the risk of infection:

Where there are suspected or confirmed cases of avian influenza, personal protective equipment should be worn, including a fit tested FFP3 respirator, protective coveralls, gloves, boots and eye protection.
Contaminated equipment should be disinfected with an appropriate disinfectant.
Good occupational hygiene practices should be followed, especially washing with warm water and soap.
Cuts and abrasions should be covered with waterproof plasters.
For advice on vaccination and use of anti-virals please refer to current Government guidelines