Avian influenza guidelines for veterinarians

Veterinarians are encouraged to collect samples from relevant morbidity and mortality events to complement current surveillance activities and provide an increased likelihood of early detection of avian influenza.

About avian influenza

Avian influenza is an infectious disease of birds caused by influenza A viruses.

Avian influenza strains are classified into 2 categories, depending on the severity of disease in poultry:

  • High pathogenicity strains (HPAI), which can cause severe clinical signs of disease and potentially high mortality rates among poultry.
  • Low pathogenicity strains (LPAI) which typically cause few or mild clinical signs.

It should be assumed that all bird species may be infected by HPAI virus.

LPAI viruses can spill over from wild birds to kept birds and reassort to HPAI viruses. All previous outbreaks of HPAI in poultry in Australia are linked to these spillover events.

While there are other diseases of wild birds that can cause similar clinical signs, HPAI should be excluded as a priority to ensure that HPAI can be detected as soon as possible and any associated risks to animal and human health can be managed.

Clinical signs

A wide range of bird species can be infected with avian influenza viruses, although waterfowl, seabirds and shorebirds are considered to pose the greatest risk.

Clinical signs in birds include:

  • lack of coordination, tremors, swimming in circles
  • twisted necks or other abnormal posture
  • inability to stand or fly
  • diarrhoea
  • difficulty breathing, coughing or sneezing
  • swelling of the head, neck and eyes
  • cloudiness or change in colour of eyes
  • sudden death.

Wild mammals

Report any unusual mortality events in marine or other mammals (particularly in areas experiencing concurrent avian mortality events).

Infected marine mammals may show signs including:

  • lack of coordination and tremors
  • seizures
  • difficulty breathing
  • nasal discharge
  • drooling
  • death, including the potential for mass mortality events.

When to investigate

Trigger conditions for avian influenza investigation and sample collection of a disease event include:

  • 5 or more sick or dead wild birds of any species, particularly those with sudden unexplained death or gastrointestinal, respiratory and/or neurological signs
  • less than 5 sick or dead wild birds of the following orders with any clinical presentation:
    • seabirds
    • waterbirds
    • shorebirds
    • birds of prey
    • scavenging birds.

Investigate events occurring in:

  • coastal locations, i.e. near migratory waterbird arrival points
  • close proximity to poultry farms and/or human populations
  • areas of high population density and numbers of waterfowl, seabirds, shorebirds or other vulnerable wild bird populations.

Surveillance target species

A wide range of bird species can be infected with avian influenza viruses, although waterfowl, seabirds and shorebirds are considered to pose the greatest risk.

A wide range of mammals have been infected with HPAI overseas, particularly marine mammals and mammals that prey or scavenge on birds.

Entry pathways

Large numbers of migratory waterbirds return to Australia every year during spring from the Northern Hemisphere via the East Asian-Australasian Flyway.

Entry from the south of Australia is also possible via migratory birds from the Antarctic and sub-Antarctic regions.

Waterfowl within the Australo-Papuan region could arrive in Australia all year-round.

Prevent human infection

Some strains of avian influenza viruses can infect people, although the current risk of H5 bird flu to people in Australia remains low.

Overseas, people who have been infected typically have had close contact with infected animals or contaminated environments.

Precautions should be taken when handling or sampling birds:

  • use appropriate personal protective equipment (PPE)
  • thoroughly clean and disinfect equipment and potentially contaminated skin.

Appropriately dispose of carcasses, used or contaminated materials.

Collecting samples

Recommended samples to be submitted from wild birds:

  • oropharyngeal and cloacal swabs (in virus transport medium or saline, chilled)
  • where swabs are unable to be collected, whole dead birds (chilled, not frozen) may be submitted.

Only freshly dead or recently euthanased birds are suitable for necropsy. Carcasses that are decomposed or scavenged are unacceptable for submission.

A maximum of 5 birds will be tested from a particular disease event (defined as a 3 km radius of where the birds were found over a period of 14 days).

Additional testing within a single event will require liaising with the laboratory and will be assessed on a case-by-case basis.

For advice on sample collection or submission of whole birds, call (07) 3708 8762 to speak with a Biosecurity Sciences Laboratory (BSL) pathologist.

Package samples

Fresh whole carcasses should be double bagged, chilled and transported to the BSL as soon as possible. The samples must be sent chilled, not frozen.

Clearly label all samples using a permanent maker:

  • anatomical location (i.e. oropharyngeal or cloacal)
  • bird ID (sequentially from 1).

Complete the specimen advice sheet (form A) for all submissions, and place this on the outside of packaging.

Ensure they are properly packaged to prevent leakage and cross contamination during transport and to maintain their integrity for laboratory testing.

Use appropriate containers:

  • transport samples in a sturdy insulated container
  • do not send specimens in glass bottles, poor-quality plastic containers, syringes or gloves
  • if swab/VTM vials are being shipped with the carcasses these should be packed in a zip lock bag, plastic box or screw top plastic container.

Place crumpled newspaper or similar absorbent material in the cooler with the bagged carcasses to:

  • fill unused space
  • hold the ice bricks in contact with carcasses
  • provide insulation
  • absorb any liquids.

Sending samples

Send the samples to the Biosecurity Sciences Laboratory.

Samples should be sent to be received during business hours (8am – 5pm) Monday to Friday. Do not send samples to arrive at the laboratory after-hours, on the weekend or public holidays, unless you have made prior arrangements with the BSL.

For highly suspect clinical cases, call 3708 8762 for advice on priority transport and/or testing.

Commercial courier

Follow the instructions for submitting samples to the BSL by courier.

If you are using a commercial courier, the birds and samples are to be consigned as ’Biological Substance Category B’ (UN 3373) and packed according to IATA packing instruction 650.

EAD Sample Transport Subsidy

Use the EAD Sample Transport Subsidy to lodge a request for sample collection.

Complete the EAD Sample Transport – Courier Booking online form and provide details of the consignment:

  • sender name
  • pick-up address
  • parcel dimensions.

Once you have submitted this form, an email will be automatically generated and sent to the BSL alerting them to your request for parcel pick-up.

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