WeCAHN Disease Updates - First Theileriosis confirmation in a dairy cow in Canada - First Theileriosis confirmation in a dairy cow in Canada - First Theileriosis confirmation in a dairy cow in Canada

Western Canadian animal disease updates

Updates on specific animal disease events across the four western provinces

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Regulatory Category- Federal:

Immediately Notifiable;
Not regulated

Regulatory Category- Province or Territory:

Immediately Notifiable;
Not regulated

Susceptible Animal Types:

Bovine

Animal Class:

Terrestrial

Disease Agent:

Theileriasis

Event Size:

1 individual

Topics:

Emerging;
Invasive Species;
Vector/Vector-borne

Organization (other):

Animal Health Laboratory (Guelph)

Start Date

Aug/05/2025

End Date

Nov/23/2025

Website

WOAH WAHIS report

First Theileriosis confirmation in a dairy cow in Canada

WOAH

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Theileriosis (Theileria orientalis Ikeda) was confirmed by the CFIA National Centre for Foreign Animal Disease in a dairy cow in Canada.

The WOAH epidemiological comments: "The Canadian Food Inspection Agency (CFIA) was notified on October 8, 2025, of a suspicion of Theileriosis in a cow with regenerative anemia located in Ontario. The cow was imported from the USA on July 15, 2025. The CFIA National Centre for Foreign Animal Disease has confirmed the sample to be positive for Theileria orientalis Ikeda through metagenomic sequencing and genotype identification. This is the first detection of Theileriosis in Canada. No control measures are undertaken to control the disease."