California researchers warn residents about return of parasitic species: 'We need to be prepared'

A previously eradicated flesh-eating maggot is moving back toward the U.S. and poses threats to humans and animals. 

Researchers say the dangerous parasite is now living within 70 miles of the Texas border. 

What's happening?

As Discover Wildlife reported, University of California, Riverside researchers have been tracking the spread of the New World screwworm. 

This parasite was once prevalent in California and the U.S. However, a successful program eradicated it by releasing sterile male flies around 60 years ago. 

Officials identified the first human case of screwworm infestation associated with travel in August 2025. Screwworms have been found in southern Mexico and Central America, often spread through the movement of infected animals. 

However, recent research indicates that the insect's population is expanding toward the U.S. 

"We need to be prepared," warned university researcher Amy Murillo, according to Discover Wildlife. 

Why is the spread of screwworms significant?

New World screwworms pose significant health and safety risks for people, pets, and livestock. They lay eggs in mammals' open wounds and develop into larvae that burrow into a person's or animal's flesh with a corkscrew motion. 

If the parasites move into new territories where they've never existed before, they could become invasive species that outcompete native species for resources. Invasive species can damage local economies and environments, wiping out entire animal populations and disrupting local ecosystems. 

What's being done about these dangerous parasites?

Studies like this one from California raise public awareness of the spread of parasites and help people understand the associated risks. 

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Led by the University of California, Riverside and funded by the California Department of Food and Agriculture, a new project is underway to lure and trap New World screwworms. 

Their customized lures mimic the odor of decaying flesh, thereby attracting the parasites. The research team plans to regularly check the traps for evidence of screwworm activity. 

By sharing their findings and ongoing monitoring, they hope to help the public recognize and prevent screwworm infestations. 

You, too, can help by sharing news of critical issues like this with people you know and having conversations about climate matters with family and friends. Knowledge is power when it comes to protecting ourselves from unexpected hazards in our environment. 

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