30 July 2026: To remind Official Veterinarians and Pet Checkers of the importance of conducting thorough inspections of animals at the point of entry to Great Britain for signs of myiasis
Updated 6 August 2026
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OVS note number: 2026/38
Date: 30 July 2026
Purpose
To remind Official Veterinarians and Pet Checkers of the importance of conducting
thorough inspections of animals at the point of entry to Great Britain for signs of myiasis (“fly strike”) and to report any suspicious findings to the Animal and Plant Health Agency (APHA). This is in response to outbreaks of New World Screwworm (NWS) in the United States of America.
Background
• New World Screwworm (NWS), Cochliomyia hominivorax, is a serious parasitic infestation that is not present in Great Britain or Europe. Defra and APHA remain vigilant for signs of the parasite and are committed to preventing its introduction into Great Britain.
• Female flies lay eggs at the edges of wounds or on mucous membranes such as the nostrils, ears, eyes, mouth or genitalia.
• Within 12–24 hours, larvae hatch and begin feeding on living tissue. They typically grow from approximately 2 mm to 1.5 cm in length.
• NWS is endemic throughout South America (except Chile), parts of Central America, and some Caribbean islands.
• There have been several recent outbreaks reported across Central America, particularly in Mexico. The USA confirmed new outbreaks in Texas on 3 June 2026 and New Mexico on 7 June 2026.
• We would like to remind Official Veterinarians and Pet Checkers to be vigilant for signs of cuts, grazes or wounds on live animals imported from North, Central and South America. It is possible for larvae to hatch during transport, which could be missed on pre-export checks. Please report any suspicious findings to the APHA.
Contact point for enquiries
Email: imports@apha.gov.uk
Imports and EU Trade Team