Many poultry diseases can be diagnosed in the field. Before specimens are submitted, the field veterinarian should obtain a complete history, examine the flock and affected birds, and perform several necropsies.

If a diagnosis cannot be made or if laboratory confirmation is required, then appropriate specimens should be submitted with a full history and description of clinical and necropsy findings. Appropriate tests for specific diseases should be requested.

Standard Containers and Equipment

Refer to relevant sections:

• Bacteriology
• Gross pathology
• Histopathology
• Parasitology
• Serology
• Toxicology
• Virology

Collection of Specimens

1. For the investigation of most diseases, submit at least 5 affected live or freshly dead birds which are, or were, showing typical signs.
2. Tissues from necropsied birds, fixed in formalin and/or fresh, are also acceptable.
3. For serology, 1 to 5 ml of blood should be collected from each of 10 to 25 birds. The jugular and wing veins are the best vessels from which to collect blood. Blood should be collected into suitable containers and allowed to clot. If the clotted blood will not reach the laboratory within 48 hours, the serum should be poured off into a suitable clean container before submission to the laboratory. The blood must not be allowed to haemolyse.
4. For bacterial or fungal culture, whole birds or fresh tissues are required. In general, swabs (with or without transport media) are not suitable, due to loss of viability of fragile organisms and/or overgrowth of contaminants. For the culture of Mycoplasma spp. or Haemophilus paragallinarum, live birds must be submitted.
5. For virology, whole birds, fresh or frozen tissues are acceptable. For virus isolation particularly for NDV and AI swabs in PBGS (which is available in 5ml plastic screw-top containers from the RVL Menangle /EMAI Virology Laboratory. If unfamiliar with the correct specimens, please contact the laboratory for advice before proceeding.

Storage and Despatch of Specimens

Live birds should be submitted in pet transport boxes or the like, with adequate air holes and absorbent lining.

The birds must not be overcrowded. The birds must reach the laboratory overnight (summer) or within 24 hours (winter), unless arrangements have been made for them to receive water and food in transit.

Sick birds must be able to withstand transport. If they are not likely to survive, they should be killed humanely and submitted chilled in an insulated container with an icebrick or ice in a sealed container. They must not be frozen.

They must reach the laboratory within 24 hours, preferably overnight.

Fresh tissues and serum should also be transported chilled, but not frozen, and must reach the laboratory within 24 to 48 hours, preferably overnight.

Formalin fixed tissues must be in leak proof containers and packaged securely to prevent breakage in transit.

If chlamydiosis or tuberculosis is suspected, particular care must be taken to avoid infection of couriers and laboratory staff. Live birds must not be sent. Dead birds should be sealed inside two plastic bags and submitted chilled inside a strong outer container. The Specimen Submission Form should be attached to the outside of the outer container and should prominently warn that chlamydiosis or tuberculosis is suspected.

Serological tests available for poultry

Serological tests are currently available at EMAI for the following diseases:

• Avian encephalomyelitis (AE)
• Avian influenza (AI)
• Big liver and spleen disease (BLS)
• Egg drop syndrome 76 (EDS) (Haemagglutinating avian adenovirus; adenovirus 127)
• Fowl adenovirus (FAV)
• Haemorrhagic enteritis of turkeys (HE; THE)
• Infectious bursal disease (IBD)
• Marek's disease (MD)
• Mycoplasma gallisepticum infection (Mg)
• Mycoplasma synoviae infection (Ms)
• Newcastle disease (ND)
• Reticuloendotheliosis (REV)
• Salmonella pullorum (Sp)

Most serological tests are flock tests. Positive results indicate that the flock has been exposed at some time to the infectious agent concerned, either by natural infection (subclinical infection or clinical disease) or due to vaccination. To confirm recent infection, paired serums are required to demonstrate flock seroconversion or rising flock titres. The tests are of limited value for individual birds.