Poultry Disease Update Victoria Bowes Animal Health Centre Abbotsford, BC

A Disease by Any Other NameÖ

So, just what is a REPORTABLE DISEASE? Diseases in livestock are officially monitored at three different levels. The Office International des Epizooties (OIE), of which there are 143 member countries, is the global animal health organization. The OIE provides 2 lists of specific diseases that are to be reported on an occurrence basis (List A) or on an annual basis (List B). The ability of a country to export livestock products into the global market will depend on its disease status specific to these listed diseases.

At the federal level, the Health of Animals Act provides for the monitoring and eradication of foreign animal disease. A List A ìforeign animal diseaseî is one that is exotic to Canada, spreads rapidly through a susceptible population causing economic hardship and would immediately threaten global trade. Examples of such diseases are Foot & Mouth Disease, BSE (mad cow) and African Swine fever. The only 2 List A poultry diseases are highly pathogenic Avian Influenza and Velogenic Newcastle Disease. The general response to a confirmed List A disease would be to quarantine, test, and slaughter with compensation paid. List B diseases generally have less of a devastating effect on animal health but have a significant impact on the export trade. The only 2 List B diseases in poultry are Salmonella pullorum and Salmonella gallinarum.

In development are another category of diseases termed ìnotifiableî diseases which are not traditionally reported at the federal or provincial level but the ìfreedom fromî status has been requested by certain importing countries. Currently in poultry these are Avian Encephalomyelitis, Fowl Cholera, Ornithosis (chlamydia) and Infectious Laryngotracheitis (ILT).

Pullorum Disease on Vancouver Island

Pullorum Disease is a federally reportable disease and Canada is considered to be pullorum-free due to a national eradication program initiated in the 1940s. In October 1997, Salmonella pullorum was isolated from a Vancouver Island backyard poultry flock. In order to maintain our pullorum-free status we had to prove eradication within one year of the initial case. A total of 49,279 premises were visited and 17,142 individual birds were blood tested revealing 28 positive flocks which were subsequently depopulated and a total of $14,146 was paid out in compensation. A final estimate of the total cost of testing and eradication was $850-900,000, shared by the commercial industry, provincial and federal governments. If Canada was unable to declare pullorum eradication and international trade was interrupted, the estimated cost just to the BC poultry producers would be 100 million dollars.

Provincially Reportable Disease

Most of the western provinces have an appointed ìChief Veterinarianî who has the authority to limit the spread of contagious disease in animals through the Animal Disease Control Act or other similar legislation. In general, provincially reportable diseases usually impact productivity and it is in the best interest of the industry to have them under control. This can be accomplished through any means deemed necessary such as issuing disease alerts to industry, quarantine, testing or slaughter. In most instances there is no compensation available for impacted producers unless the industry itself has funds available for this purpose. Each province may have itís own list of specific diseases or have a general discretionary statement to encompass any disease threat that may arise. Alberta and Saskatchewan have the discretionary clause for ìdiseases of economic importanceî while British Columbia specifically names ILT and MG in turkeys and Manitoba names ILT.

ILT Epidemiological Survey

Infectious Laryngotracheitis (ILT) is a significant viral respiratory disease of poultry that is provincially reportable in all the western provinces. Only BC allows for routine vaccination, while the other provinces generally adopt a slaughter and eradication policy. Following a recent outbreak of ILT in British Columbia, Dr. Nancy DeWith, provincial epidemiologist, conducted an epidemiological survey in order to identify any significant risk factors. A mail-in survey was sent to 397 Fraser Valley poultry producers with a return rate of 59%. The survey consisted of 22 multiple choice & short answer questions relating to specific management factors and the results compared ILT positive and negative farms. The following were identified as significant risk factors during the ILT outbreak: more barns/farm, spreading untreated manure onto local fields, short downtime, manure pit carcass disposal, poor biosecurity and adding birds during production.

ìEmergingî Diseases

The definition of this new category of disease is one that suddenly appears in a population or has previously existed but is rapidly increasing in incidence or geographic range. A good example is the West Nile Virus whose north and westward progression is closely being monitored through passive surveillance of mosquitoes and dead crows. A ever before diagnosed disease called Ornithobacterium rhinotracheale (ORT) was reported in British Columbia turkeys in April 2002.