06/05/2026
Why Wisconsinites Should Be Paying Attention to Screwworms 🚨
Screwworms have recently been detected less than 30 miles from the U.S.–Mexico border, making them a growing concern for animal health officials. While they are not established in Wisconsin, our state regularly receives pets, livestock, and rescue animals from southern regions, which increases the importance of awareness and vigilance.
Screwworms are the larvae of the New World screwworm fly. Unlike common maggots that feed on dead tissue, screwworm larvae feed on living tissue. Female flies lay eggs in wounds, surgical incisions, tick bites, or other openings in the skin. Once hatched, the larvae burrow deeper into the tissue, causing painful wounds that continue to enlarge as they feed.
Infested animals may show:
• Wounds that worsen instead of heal
• Excessive licking or irritation around a wound
• Drainage, bleeding, or a foul odor
• Visible larvae in the affected area
• Pain, lethargy, or decreased appetite
Because Wisconsin sees many animals transported from southern states and other regions, it is important for veterinarians, livestock owners, rescue organizations, and pet owners to stay informed about emerging threats like screwworms.
Awareness is one of the best tools we have to help protect our pets, livestock, and wildlife from this destructive parasite. 🐾🪰🪱
