CFIA introduces restrictions to prevent spread of New World screwworm

The Canadian Food Inspection Agency (CFIA) has announced temporary import restrictions on livestock, including horses, entering Canada from affected areas following the confirmation of New World screwworm in a calf in Texas.

Animals that originate from or were present in Texas within 21 days prior to travel will not be permitted entry at the Canadian border. The CFIA says the measure is intended to reduce the risk of introducing the pest into Canada and to protect animal health. Several U.S. states have also implemented precautionary measures.

New World screwworm is a parasitic fly whose larvae feed on the living tissue of warm-blooded animals. Infestations can cause severe injury and may be fatal if left untreated. While Canada’s climate is not generally suitable for the long-term establishment of the pest, the flies can survive for short periods during warmer summer months.

According to CFIA, livestock producers, animal owners and veterinarians are encouraged to watch for signs of infestation. Symptoms may include wounds that worsen over time, discharge, foul odours and the presence of maggots. Pet owners travelling to Texas are also advised to inspect their animals regularly for signs of infection.

New World screwworm is an immediately notifiable disease under Canada’s Health of Animals Act. Producers who suspect an infestation should contact their veterinarian, as laboratory testing is required to confirm the presence of the pest. Laboratories are required to notify the CFIA of any suspected or confirmed cases.

Quick Facts

• New World screwworm larvae feed on the living tissue of warm-blooded animals.
• The pest can affect livestock, pets, wildlife, birds and, in rare cases, people.
• New World screwworm is not found in Canada and Canadian winter conditions are generally unsuitable for its establishment.
• The flies thrive in hot, humid environments with temperatures between 25 and 30 C.
• The pest is endemic in parts of South America and the Caribbean.
• Mexico has also reported cases of New World screwworm. Canada currently restricts imports of several livestock species from Mexico and maintains strict import requirements for horses.

For more information, visit the CFIA’s New World and Old World screwworm resources.