The American war on a flesh-eating pest has drawn in British expertise, as the US battles an outbreak of New World screwworm that is devastating livestock and triggering a major biosecurity operation. The parasitic fly, which lays eggs in open wounds of warm-blooded animals, has been detected in cattle in Florida and Texas, prompting the US Department of Agriculture to deploy a controversial weapon: sterile male flies and sniffer dogs.
UK veterinarians from the Animal and Plant Health Agency have been sharing their knowledge of eradication programmes, having learnt hard lessons during the 2019 outbreak in the Cayman Islands. The collaboration comes as the American South faces its worst screwworm crisis in decades, with ranchers reporting infected cattle, deer, and even pets.
The screwworm fly, Cochliomyia hominivorax, was eradicated from the US in the 1960s but has crept back from Central America. Its larvae eat living flesh, causing gruesome wounds that can kill an animal within days. The USDA is now using a technique called the Sterile Insect Technique, releasing millions of radiation-sterilised male flies to mate with wild females, producing no offspring. Dogs trained to detect the distinctive smell of infected wounds are also being used to find cases early.
For British animal health experts, this is a familiar fight. Dr Fiona Lovatt, a sheep vet from Durham who has worked on UK biosecurity, said: "This is a stark reminder that global trade and climate change bring new disease threats. The UK must remain vigilant, especially with our own livestock sectors under pressure from rising costs." The UK has strict import rules on animals from screwworm-affected countries, but experts warn that a breach could devastate British farming, costing millions in lost productivity and animal welfare.
The US operation is a costly one, with the USDA spending over $800m since the 1950s on the sterile fly programme. But for American ranchers, the alternative is worse. A single screwworm case can cost a farm thousands of pounds in vet bills and lost livestock. The outbreak has also hit Florida's deer population, with hunters urged to report any suspicious wounds.
This is a test of international cooperation. The UK has offered its expertise on surveillance and rapid response, a move that some see as a precursor to a potential joint task force if the pest spreads further. But for now, the front line remains in the Gulf states, where the sterile flies are being dropped from planes and the dogs are sniffing out every infected animal.
For the British public, the story is a wake-up call. As our own farmers struggle with inflation and labour shortages, the spectre of a new biosecurity threat adds to the anxiety. The message from vets is clear: prepare, invest, and share knowledge. Because when it comes to flesh-eating pests, no country is an island.
