HARRISONBURG VA: (Rocktown Now) – The recent detection of the New World screwworm (NWS) in parts of the United States has raised concern among livestock owners nationwide, but agriculture experts say residents and producers in the Shenandoah Valley and across Virginia face little immediate risk.

The parasitic fly, scientifically known as Cochliomyia hominivorax, has been confirmed in a limited number of domestic animal cases—twelve total—reported in Texas and New Mexico since early June. While the discovery marks a notable development, veterinary experts emphasize that the likelihood of the pest reaching Virginia remains extremely low.

“The chance of detection here anytime soon is essentially zero,” said Dr. John Currin, a clinical associate professor at the Virginia-Maryland College of Veterinary Medicine. “Even long term, it remains incredibly close to zero.”

What Is the New World Screwworm?
The New World screwworm is a parasitic fly species that targets warm-blooded animals, including livestock, pets, wildlife, and sometimes birds. Adult flies lay eggs in open wounds or natural body openings. Once hatched, the larvae feed on living tissue, causing severe and often life-threatening injuries.
Historically, the pest has been most commonly found in South America and the Caribbean. However, since 2023, its range has slowly expanded northward through Central America, prompting heightened awareness among U.S. agricultural agencies.
“We should not be surprised if additional U.S. cases are identified,” Currin said, noting that tracking the pest in wildlife populations remains particularly challenging.

Why the Shenandoah Valley Is Low Risk
Experts point to Virginia’s climate as a major protective factor. The screwworm cannot survive in sustained temperatures below 46 degrees Fahrenheit, conditions frequently experienced throughout the Shenandoah Valley.
“Virginia is not at risk for the screwworm to become established long term,” said Virginia State Veterinarian Dr. Charlie Broaddus. “That includes regions like the Shenandoah Valley, where colder seasonal temperatures create a natural barrier.”
Additionally, federal and state agencies—including the U.S. Department of Agriculture (USDA) and the Virginia Department of Agriculture and Consumer Services—closely monitor animal movement between states to prevent the spread of pests and disease.

Precautions for Travelers and Livestock Owners
While the general public in the Shenandoah Valley faces minimal concern, experts advise those traveling with livestock or pets to affected areas such as Texas to take basic precautions.
“Anyone transporting animals to or from impacted regions should be aware of preventative measures,” Currin said. “There are effective treatments and products available to reduce the risk.”
Travelers are encouraged to consult veterinarians or USDA resources for guidance on protecting animals.

No Threat to Food Safety
Officials stress that the presence of screwworm in livestock does not pose any risk to consumers.
“There is absolutely no food-safety concern for beef or other meat products,” said Tony Banks, senior assistant director of agriculture development and innovation for the Virginia Farm Bureau Federation. “While it is a serious issue for animal health in affected regions, it does not impact the safety of the food supply.”

A Familiar Challenge with Proven Solutions
Although the screwworm may seem like a new threat, it is one the United States has successfully managed before. After widespread outbreaks in the southeastern U.S. following the transport of infested cattle in the 1930s, the USDA launched an aggressive eradication campaign.
By 1966, the pest had been eliminated using the Sterile Insect Technique—a strategy that involves releasing sterilized male flies to prevent reproduction and collapse populations.
A similar approach is being prepared again, with a new USDA facility in Texas expected to produce sterile flies to help control current and future outbreaks.

Ongoing Monitoring and Preparedness
Agricultural officials emphasize that vigilance remains key, even in areas like the Shenandoah Valley where the risk is minimal.
“As with any pest or disease situation, staying informed and engaged with animal health is critical,” Broaddus said. “If screwworm were ever detected in Virginia, we are prepared to respond quickly to protect our animal populations.”

For more information, residents and producers can visit screwworm.gov or contact USDA officials directly.