AT A GLANCE
- Canada has temporarily banned cattle and horses from Texas after New World screwworm was detected in two South Texas calves.
- Texas Gov. Greg Abbott declared a state of disaster, warning the parasite could spread during the summer.
- Abbott said Texas is willing to help speed up construction of a $750 million sterile fly-breeding facility near Edinburg.
- Officials say the outbreak is a food production concern, not a food safety issue, because screwworm larvae do not infest meat or fruit.
Canada Bans Texas Cattle After Flesh-Eating Screwworm Cases Surface In South Texas
Canada has temporarily shut the door on some Texas livestock after federal officials confirmed two cases of New World screwworm in calves near the Texas-Mexico border, raising new concerns for ranchers, food suppliers and the state’s massive cattle industry.
The Canadian Food Inspection Agency announced that cattle and horses that were in Texas within 21 days before entering Canada will not be accepted into the country. The decision came after the U.S. Department of Agriculture confirmed a second screwworm case in Zavala County, where officials are now working inside a control zone to contain the parasite.
The first Texas case was found in a three-week-old calf in La Pryor, about 100 miles southwest of San Antonio and roughly 50 miles from the Mexico border. Officials said larvae were discovered in the calf’s umbilical area, marking the first confirmed Texas case since 1966.
Days later, a second case was confirmed in a one-month-old calf in Zavala County, about 5.6 miles from the first case and still within the 20-kilometer control zone created after the first detection.
The cases are especially concerning because Texas is the nation’s leading cattle producer, and the broader U.S. cattle industry is valued at about $113 billion. A wider outbreak could threaten ranchers already dealing with high costs, tight supplies and border disruptions. Canada’s temporary ban adds another layer of pressure to the cattle trade between the two countries, which includes livestock moving for slaughter, breeding, dairy and wool production.
Abbott Pushes For Faster Sterile Fly Production
Gov. Greg Abbott declared a state of disaster Friday, saying the outbreak poses an “imminent threat” to Texas agriculture. The proclamation authorizes state resources to respond to the parasite and support containment efforts in affected areas.
Abbott also raised concern that a new $750 million sterile fly-breeding facility outside Edinburg, about 20 miles north of the U.S.-Mexico border, is not expected to open until November 2027. The facility is considered a major part of the long-term effort to stop the New World screwworm from spreading.
Abbott said Texas is willing to help the USDA accelerate construction, including spending state funds to keep work moving “24 hours a day, seven days a week.”
Without more sterile fly production, Abbott warned, “We cannot make it through a second summer.”
The Texas facility is expected to produce up to 300 million sterile flies a week once it opens. A separate USDA-funded site in southern Mexico, converted from fruit fly breeding to screwworm fly production, is expected to begin producing flies next month and eventually reach 100 million flies a week.
American-Statesman via AP)
Officials say both facilities are needed to help eradicate the fly from the U.S., Mexico and Central America.
What Is The New World Screwworm?
The New World screwworm is a parasitic fly that lays eggs in open wounds or mucous membranes of warm-blooded animals, including cattle, wildlife, pets and, in rare cases, humans. Once the eggs hatch, the larvae feed on living tissue, which can cause severe injury or death if the infestation is not treated.
The parasite was an annual warm-weather threat to U.S. cattle ranchers from the 1930s through the 1960s. It was largely eradicated from the United States by the early 1970s after officials used sterile fly releases to interrupt the insect’s breeding cycle.
Female screwworm flies mate only once. If they mate with sterile male flies, their eggs do not hatch. That method helped wipe out the pest decades ago, but many breeding facilities were later shut down. Until recently, only one major facility in the Western Hemisphere remained, in Panama, producing about 117 million flies a week.
Federal officials said past eradication efforts required about 500 million flies a week.
Officials Say It Is Not A Food Safety Issue
While screwworm can kill untreated animals, Abbott and agriculture officials stressed that the outbreak does not mean beef is unsafe to eat.
“There’s a food production issue, but not a food safety issue,” Abbott said.
Government-approved medications are available to treat livestock infestations. Experts also say the beef supply is unlikely to be significantly affected unless cattle movement restrictions expand beyond local areas or infestations reach feedlots and other places where cattle are concentrated.
Consumers are already paying record beef prices because of tight cattle supplies, but some agriculture economists say the screwworm outbreak does not change the larger supply picture on its own.
Related: Flesh-Eating Screwworm Detected 25 Miles from Texas Border, Closest Confirmed Case Yet
Surveillance Expands Across South Texas
Federal and state officials have established quarantines, movement controls and surveillance in the affected area. The USDA has already released millions of sterile flies in Texas this year, including aerial drops and ground releases of pupae.
Officials are also using scientific models to predict where the flies could move next. Texas State Veterinarian Bud Dinges said traps have been deployed up to 120 miles from La Pryor to monitor the parasite’s movement.
Canadian officials said the parasite is unlikely to become established in Canada because colder temperatures make the climate less favorable. Still, they are urging farmers to monitor livestock for wounds, discharge or foul odor, and they advised pet owners to check animals that have recently traveled to Texas.
For now, the confirmed Texas cases remain concentrated in South Texas. The question for ranchers, state officials and trade partners is whether containment can hold before summer heat gives the parasite more room to move.
