There are four main types of disease affecting poultry: metabolic and nutritional diseases; infectious diseases; parasitic diseases; and behavioural diseases.
These are conditions caused by a disturbance of normal metabolic functions either through a genetic defect, inadequate or inappropriate nutrition or impaired nutrient utilisation. These include Fatty Liver Syndrome, Perosis (or slipped tendon), Rickets and Cage Layer Fatigue.
An infectious disease is any disease caused by invasion of a host by a pathogen which subsequently grows and multiplies in the body. Infectious diseases are often contagious, which means they can be spread directly or indirectly from one living thing to another. These include Avian Encephalomyelitis, Avian Influenza, Avian Tuberculosis, Chicken Anaemia Virus Infection (or CAV), Chlamydiosis, Egg Drop Syndrome (or EDS), Fowl Cholera (or Pasteurellosis), Fowl Pox, Infectious Bronchitis, Infectious Bursal Disease (or Gumboro), Infectious Coryza, Infectious Laryngotracheitis, Lymphoid Leukosis, Marek’s Disease, Mycoplasmosis, Necrotic Enteritis, Newcastle Disease and Salmonellosis.
Parasitic diseases are infections or infestations with parasitic organisms. They are often contracted through contact with an intermediate vector, but may occur as the result of direct exposure. A parasite is an organism that lives in or on, and takes its nourishment from, another organism. A parasite cannot live independently. These include Coccidiosis, Cryptosporidiosis, Histomoniasis, Lice and Mites, Parasitic Worms (or Helminths), Toxoplasmosis and Trichomoniasis.
Abnormal behavioural patterns can lead to injury or ill health of the abnormally behaving bird and/or its companions. These include Cannibalism (or aggressive pecking).
Poultry can be affected by many types of disease, and a wide variety of pests (and behavioural problems) including those in the list below:
A few avian influenza viruses have been shown to also infect humans, but these strains do not spread easily from birds to humans. Effectively all human infections have come from contact with infected birds and no significant transmission between humans has been confirmed.
All influenza viruses ever found in birds have been influenza “Type A” viruses. Many different subtypes and strains occur, which have variable abilities to make birds ill. These subtypes are given names labelled with “H” and “N”, to reflect the genetic makeup of the virus and its ability to invade the birds’ cells. Some avian influenza viruses circulate naturally in wild birds, generally with little effect. When these viruses get into poultry (eg chickens, geese, quail), some are highly pathogenic and kill large numbers of birds.
Wild birds would not ordinarily present a threat to human health. The main threat to public health lies in a human “pandemic” of influenza that may have its origin in a bird. The virus will then be adapted to humans and unlikely to affect birds. Such an adaptation is highly unlikely to occur in Australia and would be brought here by the movement of humans rather than birds.
The take home message is a human pandemic virus, if it were to arise, would come to Australia with a human and would not involve poultry.
Original author: Ron Glanville, QDPI&F
The Asia Pacific Centre for Animal Health provides serological and virological diagnostic services to the poultry industry.
Their diagnostic laboratories are based on the University of Melbourne, Werribee campus.
“Correct and timely diagnosis is crucial and serves as the first building block in disease management. The assistance and benefits we receive through rapid and differential diagnosis are immeasurable.”
Dr Ambrosio T. Rubite, Company Veterinarian, Baiada Poultry
“We have used your diagnostic service for poultry diseases, especially for ILT, a disease that has become a major bird health issue in Australia. The work of your laboratory was both quick and accurate and it has been of great help to Inghams for the understanding and control of ILT … On behalf of Inghams, the largest poultry meat producer in Australia, I would like to thank you and the Australian Poultry CRC for providing this service to the Australian poultry industry.”
Dr Brian Burke, Group Veterinarian, Inghams Enterprises
“The PCR-based tests developed by the CRC give the benefit of both speed and typing, without the need for expensive and time-consuming culturing, as was often required before this service was available. This typing was invaluable in stamping out an outbreak of ILT we had recently, as it allowed quick confirmation and identification of the appropriate vaccine. It also allowed us to track where the outbreak virus was moving.”
“We also use the CRC’s PCR service to diagnose IB outbreaks. We have IB viruses that are not related to the traditional and present differently in the field. We can get a diagnosis and typing by simply posting down air dried swabs in an envelope and getting a typed result within 24 hours. Their PCR has also enabled us to investigate an IBH problem and show it is a different strain and not a vaccination failure as first thought. We are continuing to investigate this problem using PCR.”
Dr Ben Wells, Poultry Veterinarian and Acting President, Australasian Veterinary Poultry Association