Livestock owners are being advised to familiarize themselves with a serious animal health threat known as the New World Screwworm, a parasitic fly whose larvae can burrow into the living tissue of warm-blooded animals and cause severe, potentially fatal wounds.
The New World Screwworm, caused by the fly species Cochliomyia hominivorax, gets its name from the way its larvae screw themselves into open wounds on livestock and other animals. Unlike ordinary flies, these larvae do not feed on dead tissue — they feed on living flesh, which makes infestations especially dangerous and fast-moving.
Animals most at risk include cattle, sheep, goats, deer, and other warm-blooded creatures. Even small cuts, insect bites, or birthing wounds can serve as entry points for the fly to lay eggs. Once hatched, the larvae can rapidly enlarge a wound and cause serious damage within days if left untreated.
Livestock owners are encouraged to regularly inspect their animals for any signs of unusual wounds, foul odors coming from an animal, or behavioral changes that might indicate pain or distress. Early detection is considered critical to preventing the spread of an infestation and saving an affected animal.
The New World Screwworm was previously eradicated from the United States through a decades-long sterile insect program, but concerns have grown in recent years due to outbreaks in parts of Central America and the Caribbean. Animal health officials have warned that any reintroduction into the U.S. could pose a significant threat to the livestock industry.
Farmers who suspect they may have found a case are urged to contact their local veterinarian or state animal health officials immediately. Prompt reporting is considered essential to containing any potential spread.
Producers are also reminded to maintain good wound management practices, keep animals clean and monitored, and work closely with their veterinarians on prevention strategies during high-risk periods.
