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Annual Report

FAO/ OIE/ WHO Questionnaire - 2003
Canada

Written report to the Office International des Épizooties (OIE)

ANNUAL WRITTEN REPORT

I. New activities of the veterinary services

1. "Reportable" diseases and "notifiable" diseases

In 2003, the reportable diseases list was again revised and modified. It now includes all OIE List A diseases and the 17 OIE List B diseases listed below (see "Comments on specific List B diseases").

In May 2003, the list of reportable diseases was supplemented by the addition of two more lists of diseases prescribed as immediately and annually notifiable. The new requirements under the Health of Animals Regulations compel Canadian laboratories to report the presence of these diseases, either immediately or annually. This three-tiered listing facilitates immediate control of the most significant diseases (reportable), enhancement of surveillance for moderately important diseases (immediately notifiable) and reporting of less important group of diseases of trade significance (annually notifiable).

Dourine, eastern and western equine encephalomyelitis (EEE/WEE) and glanders which were in the "reportable" disease category in 2002 are now classified as "immediately notifiable".

The tables for OIE List A and B diseases will reflect these changes; the reportable diseases will be marked as (*) whereas the immediately notifiable diseases will be identified with a special note to that effect.

2. Bovine Spongiform Encephalopathy (BSE)

Canada's management of BSE risk is predicated on its importation policies, its feed ban, a surveillance program and the aggressive management of detected case(s).

In May 2003, a case was identified through routine surveillance and an extensive investigation was undertaken. An international team of experts reviewed Canada's epidemiological investigation and response to the case. The panel reported that the measures taken by Canada, which resulted in the detection of the case and prevented contamination of the human food chain, were successful. Among other things, to further enhance food security, the experts recommended the removal of Specific Risk Materials (SRM) from bovine carcasses to avoid possible contamination of the human food chain. Effective August 23, 2003, the Food an Drug Regulations and the Health of Animals Regulations were amended to define SRM. The new Regulations allow for the removal, and prohibit the sale, import and export, of SRM for use in food for human consumption.

II. Comments on specific List A diseases

There were no cases of any List A diseases in Canadian commercial herds/flocks in 2003.

III. Comments on specific List B diseases

Reportable Diseases

In addition to the 15 List A diseases, the following List B diseases are prescribed as reportable in Canada: anaplasmosis, anthrax, bovine brucellosis (B.abortus), bovine spongiform encephalopathy, bovine tuberculosis (M.bovis), chronic wasting disease, contagious equine metritis, cysticercosis (C. bovis), equine infectious anemia, equine piroplasmosis (B.equi, B.caballi)), fowl typhoid (Salmonella gallinarum), pseudorabies (Aujeszky's disease), pullorum disease (S. pullorum), rabies, scrapie, trichinellosis and Venezuelan equine encephalomyelitis. Many of these diseases have either never been reported in Canada, or have been eradicated.

The following reportable List B diseases were the focus of disease control and/or surveillance activities in farmed animals in 2003:

1. Anthrax

In 2003, the disease was diagnosed on 2 livestock premises in the province of Manitoba. Confirmed laboratory and field diagnoses included twenty two (22) bovines. Both premises were placed under federal quarantine and indemnity paid to owners for anthrax confirmed dead animals. Infected carcasses were controlled by burning and deep burial while remaining animals in the herds were vaccinated. No cases of anthrax were reported in Canadian wildlife in 2003.

2. Bovine brucellosis (Brucella abortus)

Canada was declared free of bovine brucellosis in 1985. No cases of bovine brucellosis have been identified since an atypical biovar 5 B. abortus was isolated from a Strain 19 B. abortus vaccinated beef cow in 1989. A field strain of B. abortus had been found in one herd of farmed bison in 1988. The disease has never been reported in farmed cervidae in Canada.

After a comprehensive review of Canada s bovine brucellosis surveillance program in 1997, the routine serological testing of market and slaughter cattle and the routine milk ring testing of all dairy cattle was discontinued in 1999. However, auction market testing of cattle 24 months and older continues in five markets in northern Alberta and British Columbia, in response to the disease risk associated with the infected free-roaming bison herds in and around the Alberta Wood Buffalo National Park.

A national bovine serum survey that was due to be conducted in 2001-2002 was postponed to 2003 to take advantage of the full implementation of the national cattle identification program to assist in the tracing of any suspicious findings. The survey is now being completed. All samples are being screened using a Fluorescent Polarization Assay and any positive samples are subject to confirmatory testing using the competitive ELISA. To date, no evidence of bovine brucellosis has been detected. A final report will be available in 2004.

3. Bovine tuberculosis (Mycobacterium bovis)

Cattle and Farmed Bison

Canada continues to near the complete eradication of bovine tuberculosis from cattle and farmed bison.

Surveillance for bovine tuberculosis in Canadian cattle and farmed bison is based on routine inspection at slaughter and submission of granulomatous and other suspect lesions for laboratory examination. This slaughter surveillance is augmented by targeted on-farm testing of cattle and routine on-farm testing of farmed bison.

In 2003, slaughter surveillance of approximately 800,000 mature cattle and bison, in Canada and in the United States (until June 2003), has resulted in no findings of bovine tuberculosis in cattle nor in farmed bison.

On-farm surveillance has been enhanced in the area around Riding Mountain National Park in the province of Manitoba, where 20 wild cervids have been found infected since 1997. The Riding Mountain TB Eradication Area (RMEA) was established around the park, where all cattle and farmed bison herds are now required to be tested. The area encompasses approximately 55,000 breeding cattle on 650 premises, representing approximately 10% of Manitoba s cattle herds (1% of Canadian cattle herds). All cattle and farmed bison herds in the RMEA are being re-tested at 12 to 36 month intervals. Periodic testing in the RMEA will continue for as long as the risk of tuberculosis continues to exist in the area. This risk-based targeted surveillance resulted in the finding of three (3) infected and one (1) exposed beef breed cattle herds. All susceptible species on the three infected premises, all susceptible exposed species on the exposed premises, as well as those animals traced from the infected herds, were destroyed and examined, with no evidence of TB spread.

All provinces in Canada except Manitoba are classified as tuberculosis-free. Manitoba has a split status: the RMEA is classified as tuberculosis-accredited-advanced according to current Canadian standard and the rest of Manitoba is classified as tuberculosis-free.

Farmed Cervidae

Canada continues to near the complete eradication of bovine tuberculosis from farmed cervids, which consist mainly of elk, red deer, elk/red deer hybrids, fallow deer and white-tailed deer. No cases of M. bovis infection were identified in Canada in 2003.

Because relatively few mature cervids are routinely slaughtered, surveillance for bovine tuberculosis in farmed Cervidae is based on the testing, every three years, of all cervid herds involved in the commercial trade of these species. In any given year, approximately 25% of the farmed cervid population is tested.

All Canadian provinces, except Ontario and Quebec are classified as tuberculosis-free areas according to current Canadian standards for cervid species. Ontario and Quebec are classified as tuberculosis-accredited-advanced areas.

Wildlife

Bovine tuberculosis in wildlife is restricted to a free-roaming bison herd of approximately 2,000 wood bison in and around Wood Buffalo National Park in northern Canada, and a herd of approximately 2,700 free-roaming elk in and around Riding Mountain National Park in the province of Manitoba.

The infected bison herd poses its greatest threat to adjacent disease-free wild bison herds. A bison management plan is in place that includes no-bison buffer zones, the killing of stray bison, and other measures to minimize the risk of disease spreading to wild bison, farmed bison, or cattle.

The infected free-roaming elk herd is believed to represent a risk of spread of bovine tuberculosis to surrounding livestock. A multi-agency Manitoba Bovine TB Management Plan has been developed and implemented to further define the disease problem, prevent the spread of infection to cattle and other farmed livestock, and eliminate the infection in the wild cervids. The Riding Mountain TB Eradication Area (RMEA) has been established as a management measure to address the risk to the farmed animal population.

4. Bovine Spongiform Encephalopathy (BSE)

BSE was named a reportable disease in 1990, and a national surveillance program was implemented in 1992. In May 2003 a case was detected in a beef cow in the province of Alberta. The index herd was depopulated and on the basis of the epidemiological investigation, all susceptible animals whose relationship to the index case did not preclude the possibility of them having been similarly exposed to the agent of BSE, were also depopulated. Over 2000 animals were destroyed and tested in the context of the BSE investigation, all with negative results. Federal compensation was paid for all animals ordered destroyed. The investigation to more accurately describe Canada s exposure to the agent of BSE is ongoing.

In December 2003, a second case of BSE was detected in North America. The subsequent epidemiological investigation attributed this case to dairy cow that originated in Canada. All susceptible animals resident in Canada, whose relationship with this case indicated the potential to have been similarly exposed to agent of BSE were identified, traced and when found to be alive, depopulated. Federal compensation was paid for all animals ordered destroyed.

Both cases of BSE attributed to Canada involved animals born prior to the implementation of ruminant feeding regulations in 1997.

During 2003, over 5600 samples were tested for BSE (final figures are being compiled). These samples were acquired through the national BSE surveillance program and the investigation of the BSE case identified in May. Tissue samples were evaluated using immunohistochemistry within the Canadian Transmissible Spongiform Encephalopathy Laboratory Network. Rapid test methodologies were introduced to the diagnostic network during 2003 to support increased BSE surveillance testing in 2004.

5. Chronic Wasting Disease (CWD)

A national control program for CWD was implemented in 2000 and the disease became reportable in 2001. Suspicious cervids are destroyed and tested for CWD. Where an animal has been identified as having CWD, the herd is investigated to determine the entry of CWD into the herd. All cervids exposed to an infected animal in the last 36 months are destroyed, including any that have left the premises. Cervids that have left the premises and were last exposed between 36 and 60 months before are kept under surveillance by federal veterinarians until 60 months after their last exposure.

In 2003, in spite of continuing high surveillance rates, no new farms infected farms were discovered. One farm determined to be infected in late 2002 was destroyed. All traceouts of cervids from the infected farm were negative. The mandatory provincial CWD surveillance programs in Alberta, Saskatchewan, Manitoba and the Yukon continue. The programs require all farmed cervids more than 12 months that die or are slaughtered or that are down, disabled or diseased be submitted for testing. In 2003, 16,476 animals were tested in these jurisdictions, all with negative results.

Surveillance of free ranging (wild) cervids from hunter shot submissions especially in the targeted high risk areas continued. A total of 16 positive samples was found in the 7,778 tested in Saskatchewan in 2003.

In total, in 2003, 18,189 and 10,427 tests were performed on farmed and wild cervids, respectively.

After extensive preparation, in conjunction with the Canadian Food Inspection Agency Center of Expertise for CWD, the province of Alberta laboratory is using the Biorad test for surveillance purposes. All other laboratories use the immuno-histochemistry test.

6. Enzootic Bovine Leukosis (EBL)

EBL testing is part of the Canadian Artificial Insemination programs (domestic and export). At the end of 2003 there were also 74 cattle herds enrolled in the Canadian Health Accreditation Program for EBL and 72 herds were EBL accredited with a total of 8,527 animals.

7. Equine Infectious Anemia (EIA)

During 2003, 58 horses were found EIA infected, most of them in the provinces of Alberta (22) and British Columbia (28). Positive horses were also found in three other provinces: Ontario (1), Manitoba (5) and Saskatchewan (2). With a few exceptions, all positive animals were ordered destroyed with compensation paid to the owner. A few owners avail themselves of the option to permanently quarantine the reactor in suitable vector-proof facilities. A total of 80,506 serological tests for EIA were performed for routine domestic and international requirements for racing, exhibition, breeding, sale and stabling, as well as in response to suspected or confirmed disease situations. In 2003, the reactor rate was 0.07%, down from 0.247% (193 / 78,090) in 2002.

8. Porcine brucellosis (Brucella suis)

Surveillance for porcine brucellosis is based on a national serological survey of slaughter sows that is conducted every three to four years. The most recent survey was conducted in 2001-2002 while testing of the more than 15,000 samples was completed in 2003. The results, including additional investigation of suspicious reactions indicated that Canada continues to be free of porcine brucellosis.

B. suis biovar 1 has never been found in Canadian swine. B. suis biovar IV occurs in Rangifer species (caribou and reindeer) in the Canadian Artic. Movement controls within the country prevent these animals from entering the livestock producing areas of Canada.

9. Rabies

Canada reported 265 laboratory confirmed and1clinically diagnosed cases of rabies in domestic and wild animals in 2003. This represents a decrease of 24% from the 349 rabies cases reported in 2002. The decrease can be attributed to lower numbers of reported cases in foxes (65 in 2002 vs. 28 in 2003) skunks (101 in 2002 vs. 76 in 2003), and raccoons (26 in 2002 vs. 16 in 2003).

In 2003 wild animals accounted for approximately 90% of all positive cases (bats: 43.4%; skunks: 28.7%; foxes: 10.6%; raccoons: 6.0%). Among domestic species, rabies was most often found in cattle (4.2%). The majority of rabid animals were submitted by Ontario (127), Manitoba (50) and Saskatchewan (24). No cases of rabies were reported from Prince Edward Island, North West, Nunavut and the Yukon Territories.

Ontario was the only province, in 2003, to report cases (16) of raccoon variant strain of rabies. Since the first incursion of that particular variant of rabies into Ontario in 1999, a total of 191 such cases have been confirmed by the Canadian Food Inspection Agency laboratory.

In 2003, one human case of rabies was reported from the province of British Columbia where a 52-year old man died of a bat-associated rabies virus. The last human death from rabies in Canada occurred in the province of Quebec in 2000, where a bat variant of rabies was also implicated.

10. Scrapie

Scrapie is a reportable disease in Canada. It is known to exist in the country at a very low level. During 2003, scrapie was diagnosed in 12 sheep flocks; 4 in Quebec, 1 in Ontario, 6 in Saskatchewan and 1 in Alberta. Under the scrapie program, 5360 ovines were destroyed on 36 premises, with $1.7 million (CAD) in compensation paid to the owners. A mandatory national identification program for sheep will be implemented January 1, 2004. The implementation of a revised scrapie eradication program was delayed and is now scheduled to be implemented during 2004. The combination of the mandatory identification and the revised program will facilitate the investigation of any detected case. Utilization of genetic screening in the revised eradication program will focus on those sheep of greatest risk for disease transmission. During 2003, genetic screening was applied in several infected flocks as a pilot investigation of the proposed program changes.

11. Trichinellosis

Trichinellosis in swine has only an exceptional occurrence in Canada. Since 1983, there have only been three discoveries of this parasite in Canadian swine. In 2003, approximately twenty-three (23) million pigs were slaughtered and monitored. All animals tested, including farmed wild boars, were negative. Approximately 65,000 horses slaughtered were tested and found negative using digestion techniques. The testing of 15,579 samples from the 2001-2002 national swine serological survey was completed in 2003. There were no positive results (Indirect ELISA using excretory-secretory antigen in compliance with OIE recommendations).

Non-Reportable Diseases

Non-reportable List B diseases, which have not been known to occur in Canada include: heartwater, screwworm, babesiosis of cattle, theileriasis, trypanosomiasis, contagious caprine pleuropneumonia, Nairobi sheep disease, epizootic lymphangitis of horses, horse pox, Japanese encephalitis of horses, surra, Venezuela equine encephalomyelitis, myxomatosis, viral haemorrhagic disease of rabbits and porcine enterovirus encephalomyelitis (formerly Teschen/Talfan disease).

Aquatic Animal Diseases Notifiable to OIE and others of Significant Importance

(a) Pacific Coast:

Viral Hemorrhagic Septicemia Virus (VHSV) - North American (NA) Strain

There have been some isolations of the virus with minimal mortalities among farmed salmon.

Infectious Hematopoietic Necrosis Virus (IHNV)

IHNV is endemic in wild sockeye stocks throughout British Columbia. In farmed Atlantic salmon (Salmo salar) a total of 36 farms in five different areas were affected by the disease between May 2001 and December 2003, and the provincial government has put into effect stringent isolation, biosecurity and other disease control measures to limit the farm to farm spread. Under these measures this epizootic now appears to be contained. During their routine screening program for a number of disease agents, the Fish Pathology Program (FFP) of the Department of Fisheries and Oceans found IHNV in 4 sockeye stocks: Tankeah, Babine, Genessee, and Amback.

b) East Coast:

Cultured Fish:

Infectious Salmon Anaemia Virus (ISAV)

A clinical outbreak in the province of Nova Scotia (the second reported for this province) occurred at the same site as the first reported clinical outbreak in 2000. Affected cages were harvested (accelerated marketing).

In the province of New Brunswick (NB), two sites were positive for ISAV in 2003, and approximately 20,000 fish were harvested. Under the NB Surveillance Program, for a cage to be considered positive, a minimum of two fish must test positive by two different methods. If a cage is classified as positive then the cage is harvested and marketed.

Infectious pancreatic necrosis Virus (IPNV)

The virus continues to be found (Atlantic zone) in carrier state in all species of salmonids, in a variety of age classes, predominantly from facilities with surface water influence. However, no mortality problems were reported from those facilities testing positive for IPNV.

Aquareovirus

Again, in 2003, this virus was isolated from juvenile halibut showing some liver pathology. It is to be noted that challenges performed in 2000/2001 with this virus in juvenile halibut (presented at the European Association of Fish Pathologists meeting in Dublin 2001) failed to cause mortality.

Y. ruckerii (causative agent of Enteric Redmouth disease)

This bacterium was isolated from freshwater facilities in the provinces of NB and NS from salmonid hosts (Atlantic salmon (Salmo salar) and Arctic charr (Salvelinus alpinus)). In ¾ sites Y. ruckerii was isolated in absence of reported inflated mortalities. The significance of this isolation for the 4th site is unknown. In one of these facilities, the fish were subjected to spawning stress and co-infection with Renibacterium salmoninarum.

Atypical Aeromonas salmonicida

This agent was isolated from cod (pre-adult) held in sea cages in the province of NB and from cod held at a NB research facility. The fish held at the sea cage site were destroyed to possibly prevent other fish species held at the site from becoming infected.

Multi-resistant Aeromonas salmonicida

The agent was isolated from sites in the provinces of NB and NS. Isolate was resistant to standard commercially available antibiotics. This isolate was spread through movements of fish. Fish received antibiotic treatment(s). A variety of other farm management practices were also implemented.

Wild Fish:

Infectious pancreatic necrosis Virus (IPNV)

The virus was isolated from an Atlantic salmon collected in the wild but deemed an aquaculture escapee upon collection. It was also isolated from a brook trout mortality (Aeromonas hydrophila septicemia detected as well) collected from a river in the province of Nova Scotia.

Infectious Salmon Anaemia Virus (ISAV)

The virus was isolated from one Atlantic salmon collected in the wild but deemed an aquaculture escapee upon collection. The fish had skin damage, resembling that possibly caused by a predator.

Lymphocystis virus

A striped bass (Morone saxatilis) was collected and submitted due to an extensive skin infection with the virus (an iridovirus) causing lymphocytis.

"Aquatic birna virus"

Gaspereau (Alosa pseudoharengus) collected from a river in the province of NB tested positive for an "aquatic birna virus". The observed cytopathogenic effect (CPE) was neutralized using Connaught monovalent anti-Infectious Pancreatic Necrosis Virus (IPNV) antiserum. A sample showing CPE was also forwarded to the Department of Fisheries and Oceans Molecular Biology Unit and tested positive for aquatic birnavirus using RT-PCR analysis. The primers used for detection of IPNV by RT-PCR are capable of detecting nucleic acid from several members of the family Birnaviridae to which IPNV belongs.

Aeromonas salmonicida

The agent was isolated from Atlantic salmon mortalities collected in the province of New Brunswick, from the Saint John and Miramichi River drainages.

IV. Comments on other diseases

West Nile Virus (WNV)

WNV, identified for the first time in the Western Hemisphere in the United States of America in 1999. In Canada the first case of WNV was detected through dead wild bird surveillance in 2001. For the last three years, WNV surveillance in Canada has been a collaborative effort, coordinated by Health Canada, federal, provincial/territorial ministries and agencies as well as key national organizations such as the Canadian Cooperative Wildlife Health Centre (CCWHC). Surveillance for WNV in wild birds was carried out across Canada in 2003 through a multi-agency program coordinated by the Canadian Cooperative Wildlife Health Centre and including Health Canada and all provincial governments.

In 2003 (as reported on January 12, 2004), 11,332 birds had been tested and positive birds had been identified in the provinces of Nova Scotia (17), New Brunswick (6), Quebec (846), Ontario (242), Manitoba (133), Saskatchewan (157), Alberta (232). Newfoundland, Prince Edward Island, and British Columbia as well as all the Canadian Territories did not report cases of WNV in their bird populations in 2003.

In 2003 (as reported on January 12, 2004), combined presumptive and confirmed positive cases in horses amounted to 445 across 6 provinces: Nova Scotia (1), Quebec (8), Ontario (41), Manitoba (53), Saskatchewan (162) and Alberta (180). And in 2003, no cases of WNV in horses were reported from Newfoundland, New Brunswick, Prince Edward Island, British Columbia and the three territories (North West Territories, Nunavut and Yukon).

Under Canada's Health of Animals Regulations, WNV is now an "immediately notifiable disease" (see Section I - New activities of the veterinary services).

Complete reports, with tables for OIE lists A, B and C diseases and zoonoses are available on the Canadian Animal Health Network (CAHNet) website under "Reports".