The Canadian Food Inspection Agency lifted the additional requirements on September 10, 2009, following the latest information from the United States Department of Agriculture.
The disease was found in a seven-year-old Missouri quarter horse early in June.
The disease is caused by a protozoa, Theileria equi, which can be carried by certain kinds of ticks. The ill animal and others on the affected premises were examined for ticks. No ticks were found.
While equine piroplasmosis is a tick-borne disease, it can also be spread by contaminated needles.
Its symptoms include weight loss, jaundice, fever and anaemia.
The United States routinely screens all imported horses for piroplasmosis.
The last reported occurrence of the disease in the US was in February in Florida. That investigation involved the quarantining of 25 properties and the tested of more than 200 horses. Horses found to be infected with the disease were euthanized.