A parasitic crisis is unfolding in the United States, where the New World screwworm—a flesh-eating maggot—has been detected in cattle and livestock in southern states. The infestation, which can kill an animal within days, has prompted the US Department of Agriculture to deploy a combined force of sterile flies and trained detection dogs. For UK farmers and the biosecurity apparatus that protects them, the outbreak is a stark warning.
The screwworm, *Cochliomyia hominivorax*, lays eggs in open wounds. The larvae burrow into living tissue, causing severe pain, infection, and death if untreated. The last major US outbreak was eradicated decades ago using the same sterile insect technique now being deployed. But climate change and increased livestock movement have raised the risk of re-emergence. The UK Animal and Plant Health Agency (APHA) has issued an advisory to British farmers importing livestock or genetic material from affected US states, stressing rigorous inspection and biosecurity protocols.
“This is not just a US problem,” said Dr. Eleanor Marsh, a veterinary biosecurity expert at the University of Reading. “We have our own diseases to worry about, but increasing global trade means we can’t be complacent. The screwworm would find plenty of hosts here, from sheep to poultry. The public should also know it can affect pets and even humans if wounds are exposed.”
The trade of live animals, hides, and even equipment from infected zones is now under scrutiny. UK farming unions have called for temporary restrictions, but the government is balancing trade commitments with precaution. For farmers like John Ackroyd, a sheep farmer in Yorkshire, the news is deeply worrying. “We’ve fought off bluetongue and avian flu. But a parasite that eats them alive? That’s a waking nightmare. I’m checking my sheep for any cut or scratch now.”
The UK’s biosecurity framework, codified after foot-and-mouth disease outbreaks, relies on border surveillance and rapid response teams. The APHA has urged vets to report any suspicious wounds in livestock. The National Farmers’ Union has set up a helpline for members seeking advice on imports.
Labour relations are also affected. The Transportation Workers Union, representing livestock hauliers, has flagged concerns about drivers bringing in potentially contaminated loads from the US. “Our members don’t get paid enough to take these risks,” said a union spokesperson. “They need protective gear and training, not just a leaflet.”
For the average Briton, the crisis may seem distant. But the cost of bread and meat could rise if the US cattle industry is crippled. Screwworm infestations in the 1930s cost the US livestock sector billions in today’s money. Any spike in global beef prices hits British households already squeezed by inflation.
However, there is hope. The sterile fly program has a proven track record. Scientists at the UK’s Pirbright Institute have offered to assist US counterparts. “We have world-leading expertise in insect-based disease control,” said Prof. James Horton. “Collaboration is essential. This is a fight we can win, but only if we stay vigilant.”
As the US battles the parasite in Florida and Texas, UK farmers watch and wait. For now, the risk remains low, but the message from biosecurity officials is clear: prepare, inspect, and report. Because once the screwworm gets in, it is almost impossible to get out.
