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 May 12 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. 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.

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 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.