Avian influenza

Avian influenza is restricted and prohibited matter under the Biosecurity Act 2014.

If you suspect avian influenza in birds within Queensland, contact us immediately on 13 25 23 (business hours) or the Emergency Animal Disease Watch Hotline on 1800 675 888 (after hours).

Avian influenza (AI) is a highly contagious viral infection of birds, including poultry. There are many strains of the virus, some of which cause no clinical signs while others can be devastating to susceptible birds. Turkeys and chickens are particularly susceptible to the AI virus.

Cause

AI is caused by a virus Orthomyxovirus, type A.

Other names

Bird flu ; fowl plague

Distribution

Outbreaks of AI have occurred in domestic poultry since 1976 in Victoria, NSW and Queensland. The most recent outbreak was in Young, NSW in 2013 which affected commercial layer flocks. All outbreaks have been successfully eradicated.

An overseas example is the highly pathogenic H5N1 strain that has occurred in Asia, Africa and Europe since 2003, affecting millions of poultry, some species of wild birds and, infrequently, humans.

Hosts

Wild birds are frequently the source of AI infection in domestic poultry. Wild birds may contaminate domestic poultry feed or water supplies which, when ingested, may lead to infection or disease. Infected backyard poultry and live bird markets can be a source of AI virus for commercial poultry.

Affected animals

birds; poultry; turkeys; chickens

Symptoms

AI can be confused with a number of other diseases that have similar clinical signs. Early detection and reporting any unusual signs is essential for rapid control of the disease.

Clinical signs are variable and can be affected by the existence of other diseases, the age of the birds, the environment and the severity of the virus itself.

In very severe forms the disease appears suddenly and birds can die very quickly (within 24 hours), sometimes without showing the classical signs of the disease which include:

  • depression
  • excessive lacrimation (secretion of tears)
  • coughing, sneezing and rales (rattling sound in the lungs)
  • swelling of the head, eyelids, comb, wattles and hocks
  • purple discoloration of the wattles, combs and legs
  • decrease in egg production
  • production of soft-shelled eggs
  • profuse watery diarrhoea
  • difficulty breathing
  • high mortality.

In less severe forms, signs may also include:

  • cold symptoms (nasal discharge, coughing and sneezing)
  • swelling of the face
  • nervous signs
  • diarrhoea.

Impacts

An outbreak of highly pathogenic (HPAI any subtype) or low pathogenic (LPAI H5/H7) avian influenza in Australian poultry could have serious social and economic impacts. Trade and markets will likely be disrupted and infected properties will have requirements (including movement control) imposed to control the disease under legislation.

It is critically important that any suspicion of this disease is immediately reported. If HPAI or LPAI (H5/H7) is detected, it is important to eradicate it as quickly as possible in order to control further spread and reinstate Australia's disease-free status for trade purposes.

How it is spread

Low pathogenic strains of the AI virus are found in some wild bird populations in Australia, in particular waterfowl such as ducks and geese.

Spread from wild birds or waterfowl to domestic flocks occurs by either direct contact with infected wild birds or through in-direct contact such as contaminated pasture, water or feed.

Once a flock has been infected, the virus has the potential to change from a low pathogenic strain, to a high pathogenic strain and potentially cause a significant disease outbreak.

In recent overseas incidents, spread of AI virus between flocks has been mainly due to poor biosecurity involving:

  • movement of infected birds
  • movement of contaminated feedstuffs, equipment, vehicles, personnel clothing and footwear on commercial or non-commercial properties
  • live bird markets (movement of infected birds, contaminated crates and contaminated vehicles)
  • egg collection
  • depopulation activities that infect nearby properties with birds
  • use the same transport vehicle for dead bird pickup or waste collection from different premises.

Risk period

Incubation period of 3–5 days. The virus is able to survive in the environment for variable amounts of time. It will usually survive the longest in water and the faeces of infected birds.

Monitoring and action

It is important that all poultry farmers and owners, bird fanciers and wild bird carers and watchers are aware of this disease and remain vigilant for any unusual disease occurrence.

Birds which appear to be ill or dead should not be handled without suitable protective clothing and equipment (face mask, gloves).

Comprehensive plans to respond to and control an outbreak of highly pathogenic avian influenza in poultry exist at a national level and have been developed in consultation with peak poultry industry body groups. The nationally agreed strategy is outlined under AUSVETPLAN for the poultry industry. It includes:

  • immediate stamping out and disposal of infected and in-contact birds to remove the major source of virus
  • strict quarantine and movement controls to prevent the spread of infection
  • decontamination to remove and reduce the virus
  • tracing and surveillance to locate the source of infection, locate other infected premises and determine the extent of the infection
  • zoning or compartmentalisation to define infected and disease-free areas.

If you suspect avian influenza in birds, you should immediately notify Biosecurity Queensland on 13 25 23 (business hours) or the Emergency Animal Disease Watch Hotline on 1800 675 888 (after hours) and seek veterinary advice.

Control

Prevention

Prevention of AI is through routine use of on-farm biosecurity measures that can help to prevent the introduction of the disease into the flock. It is the responsibility of all bird owners (commercial and non-commercial) to implement biosecurity measures to protect their animals from pests and disease.

In free range situations, the risk is increased as birds are outside and have a higher chance of coming into contact with wild birds or their droppings, compared to flocks that are kept indoors.

Vaccination

Control of AI without the use of vaccination is preferred. Vaccination has not been necessary in Australian outbreaks to date, but its usefulness has been demonstrated in overseas outbreaks. If the disease is spreading at a significant rate, vaccination, enhanced biosecurity and other infection control measures may be implemented to protect flocks from infection.

National protection

The Australian and Queensland Governments understand the importance of protecting our poultry industry. Primary producers, relevant government bodies and the public are alerted to disease events overseas and of the appropriate preventive action. Measures taken to heighten biosecurity in Australia and Queensland for avian influenza include:

  • banning the importation of live poultry, aviary birds and eggs into Australia from countries that have avian influenza
  • inspection, quarantine and testing of poultry products (meat and/or egg products and products including feathers) and live birds at airports, seaports and international mail handling facilities
  • investigation of reported suspect infection in birds or poultry by Biosecurity Queensland veterinary officers and inspectors
  • Biosecurity Queensland and other agencies working closely with poultry producers to follow good biosecurity practices and protect their flocks from exposure to the virus
  • Biosecurity Queensland veterinary laboratories routinely screening all bird samples submitted for examination.

Further information