Bluetongue disease status officially downgraded

Five types of bluetongue, a disease affecting cattle and other ruminants, have been officially been downgraded in Canada to “immediately notifiable” from “federally reportable.”

The Canadian Food Inspection Agency, which said last summer it planned to loosen the rules in Canada’s Reportable Diseases Regulations and Health of Animals Regulations dealing with the five common U.S. serotypes of bluetongue (Nos. 2, 10, 11, 13, 17), announced Wednesday the rules have been amended.

Any suspected or confirmed case of a “federally reportable” disease must be reported to the CFIA, which then applies control measures. But there are no response programs for “immediately notifiable” diseases, other than that laboratories are required to report confirmed diagnoses to the CFIA.

Reports from labs testing for the disease are expected to allow CFIA to track a disease’s prevalence in livestock and support international reporting and certification requirements.

No human health or food safety risk is known to be connected to bluetongue, CFIA emphasized Wednesday. It affects domestic and wild ruminants, and is only spread by way of biting midges.

The range of animals that can be infected with bluetongue virus includes most ruminants, but the severity of disease varies among different species, CFIA said.

In Canada, biting midges are only present in British Columbia’s Okanagan Valley and in southern parts of Manitoba, Saskatchewan and Alberta, where the midge has “limited ability” to survive and spread bluetongue.

Bluetongue cannot be spread directly from one infected animal to another. Infection in cattle, goats and elk is “generally unapparent or mild.” Sheep and white-tailed deer may be severely infected and death is possible.

The five affected bluetongue types are considered “endemic” in the U.S. and Wednesday’s regulatory amendments reflect the “highly integrated nature of the Canadian and American livestock markets,” CFIA said.

But maintaining the U.S. serotypes on the “immediately notifiable” list is expected to allow the CFIA to investigate and assess whether the risks to livestock from the five downgraded U.S. serotypes have changed.

All remaining types of bluetongue, exotic to the U.S., are still listed as “federally reportable.”

“The changes are based in science, and do not affect Canada’s international reporting obligations to trading partners and the World Organization for Animal Health (OIE),” CFIA said.

The Okanagan Valley is the only area in Canada where the disease has occurred and would arguably provide the most suitable climatic conditions for the spread of bluetongue of any area in Canada, CFIA said. But even then, significant clinical disease or death losses in sheep and white-tailed deer have only been reported once, in 1987-88.

Furthermore, CFIA said, a 2004 study found that the midge species known to transmit the disease in the U.S. is at the “northernmost limit” of its range and has a “very poor capacity” to transmit bluetongue in Western Canada. And so far as is known, bluetongue virus can’t overwinter in Canada.

In comments last summer supporting the proposed change, Alberta Beef Producers said “the risk bluetongue poses to Canada’s livestock industry is insignificant compared to the damages due to the restriction of normalized trade with the U.S.”

The Manitoba Cattle Producers Association, meanwhile, wrote it “believes that the CFIA’s research related to bluetongue — in addition to protecting the health of livestock — will also help to resolve some of the long-standing trade issues between Canada and the U.S.”

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