New World Screwworm Found in Texas

 By the Missouri Department of Agriculture

The United States Department of Agriculture Animal and Plant Health Inspection Service (USDA-APHIS) has confirmed the presence of New World Screwworm (NWS) in the United States. On June 3, 2026, USDA confirmed NWS in a 3-week-old calf in Zavala County, Texas.

NWS is a serious pest that affects livestock, pets, wildlife and less commonly, people and birds. NWS larvae burrow into the flesh of living animals, causing serious damage to livestock and economic losses to producers.

The Texas case is the first detection of NWS in the U.S. since northward progression from Central America was observed in 2023. In preparation for the potential re-emergence of NWS in the U.S., Missouri assembled a New World Screwworm joint working group. Led by State Veterinarian Steve Strubberg, the working group is comprised of representatives from USDA, Missouri Department of Agriculture, University of Missouri Extension, Missouri Department of Conservation and Missouri Department of Health and Senior Services.

The working group prepared a Missouri NWS Response Plan. In light of the U.S. detection, Missouri has activated the Response Plan.

Animal movement into Missouri

Any species traveling from an infested state, but not an infested zone, can enter Missouri with a Certificate of Veterinary Inspection (CVI) that includes a statement “All animals in shipment do not originate from or transit through a NWS infested zone.”

Any species that originates from an infested zone must meet the movement requirements for the state of origin and obtain a permit from the Missouri State Veterinarian’s office and have a CVI that states “all animals listed were individually inspected and found free of wounds.”

Steps to protect your animals

Prepare. 

Develop and implement strong fly and tick protocol for animals.

Clean, treat and cover open wounds.

If possible, delay practices which cause skin openings such as castration, dehorning or branding. Treat areas where these practices are performed.

Register your farm for a premises ID so the Missouri Department of Agriculture can notify you if NWS is confirmed in the state.

Inspect. 

Regularly monitor animals for signs of infection or maggots, especially around areas of castration, dehorning, branding, umbilical site, scrapes, lesions or a tick-feeding site.

Know the signs: 

Bloody or light-colored drainage from a cut or wound.

A cut or wound that rapidly enlarges for seemingly no reason.

White or cream-colored runny substance (the eggs) in and around a wound.

Presence of fly larvae (maggots) in wounds.

Irritated behavior and signs of pain.

Head shaking.

Reduced appetite.

Fever and other signs of secondary infection.

Foul odor or smell of decay.

Act.

If you see a live animal with signs of infestation, report it immediately.

For livestock and pets, contact your local veterinarian or the MDA Animal Health Department at (573) 751-3377.

For wildlife, contact the Missouri Department of Conservation at (573) 522-0142 or report it online.

It is important to note that this detection does not impact food safety and the U.S. food supply is safe.

Beef Prices Continue to Rise

Recent data from the U.S. Bureau of Labor Statistics shows the average retail price of ground beef rose to a record $6.12 per pound in June 2025.

This is up from $5.98 in May and $5.47 a year earlier in June 2024. Prices for certain beef cuts might ease with the end of peak grilling season, but ground beef prices remain historically high.

“Tight cattle supplies and continued strong demand are keeping beef prices high,” said Danyelle Chinn, research analyst at the University of Missouri Rural and Farm Finance Policy Analysis Center (RaFF). “It’s a positive signal for Missouri’s cattle producers, but it also means consumers are feeling the impact at the store.”

How we got here: Drought and high input prices

“Multiple years of drought and low profitability forced beef producers to shrink their herds in recent years,” said Wesley Tucker, MU Extension agricultural business policy specialist.

Cows need forage to graze in the summer and hay to eat in the winter. Several years of drought forced producers to make tough decisions. With limited forage options, producers had to sell chunks of their herd and were not able to retain heifers to replace them.

“A large section of the production factory – the cow herd – has been lost,” Tucker said.

High input prices also drove up the cost of production. Limited profitability gave producers little incentive to expand.

“Current beef cow numbers are the lowest they have been since 1961,” Tucker said.

Mexico and tariffs

New World screwworms have slowly migrated north from southern Mexico, forcing the USDA to close the border to cattle imports to protect U.S. cow herds from this parasite.

“Feedlots in southern parts of the country rely on Mexican cattle to keep feedlots full, so this further shortens the beef supply,” Tucker said. With the shrinking domestic beef herd, imports have become an important component to keeping grocery store shelves full.

As trade policy continually develops, the threat of tariffs could further affect available supplies.

Steady demand

Even as prices have risen, consumers continue to buy beef rather than switch to alternative proteins like pork or chicken. With summer well underway and grilling season at its height, demand is gobbling up limited supplies.

The extremely strong beef demand index is supported by consumer weight loss programs that emphasize a high-protein diet, Tucker said.

“Markets are the result of supply and demand,” he said. “The current situation is the perfect storm of limited supply and strong demand colliding to produce record prices.”

When could we see a reduction in beef prices?

“Greater supply or lower demand could produce cheaper prices,” Tucker said.

For supply to increase, beef producers must rebuild the herd. But means producing less in the short run: If more heifers are retained for breeding purposes, feedlot inventories fall, reducing the number of animals available for slaughter. It takes multiple years from the time a heifer is retained and bred until her calf enters the food chain and increases production.

“In the short run, consumers could face even higher prices as the herd is being rebuilt,” Tucker said.

If the economy were to stumble and disposable income were to falter, consumers might switch to cheaper proteins and avoid higher priced cuts of meat, he said. Any change in the economy or global markets affecting beef exports can affect the price of beef.

“But for now, consumers are forced to stretch their pocketbook at the meat case,” Tucker said.

 

Missouri State Highway Patrol Investigates False Missouri New World Screwworm Claims

On June 6th, the Missouri Department of Agriculture announced that the Missouri Highway Patrol, the Missouri Attorney General, and the Missouri Department of Agriculture are investigating false claims that the New World Screwworm is in Missouri.

The New World Screwworm had been eradicated from the US in the 1960’s. It had been contained south of Mexico until 2022. However, it then turned up in two Mexican provinces and there is a widespread fear in the agriculture community that it will return to the US at some point. The USDA estimates that the cattle industry saves $3 billion per year thanks to the eradication of this pest.

On May 9th, we printed an opinion piece from the National Cattlemen’s Beef Association discussing concerns regarding what they saw as the Mexican Government’s  lack of response to the problem and even actively denying flights carrying sterile flies permission to land. However, that piece made no references to the New World Screwworm being in Missouri or even the US.

On May 27th, KTTN printed a press release that falsely stated that the New World Screwworm was already in Missouri. The station subsequently retracted the post, but the Missouri Department of Agriculture says that the publication of that piece set off a frenzy of animal health concerns, market scare, and detriment to consumer trust.

The Missouri Attorney General, Highway Patrol, and Department of Agriculture are seeking to determine whether the source of the false information was a malicious actor deliberately seeking to create panic in agricultural markets.

As flies, the New World Screwworm lays eggs in the wounds of cattle. The larvae burrow into the skin of calves, causing injury and sometimes death. Before it was eradicated, producers had to monitor their animals constantly.

 

Opinion -- USDA Seeks to Protect Cattle Industry from New World Screwworm

By the National Cattlemen’s Beef Association

The National Cattlemen’s Beef Association announced support for U.S. Secretary of Agriculture Brooke Rollins’ actions to protect the American cattle industry from the rising threat of New World screwworm.

“The U.S. spent millions of dollars to eradicate New World screwworm from our borders in the 1960s but unfortunately, we are now facing this dangerous threat again,” said NCBA President and Nebraska cattleman Buck Wehrbein. “Screwworm is very destructive and could cost American producers millions of dollars a year if it reaches us. Americans have been investing in prevention efforts in Central America for decades, but we can’t stop this without Mexico’s participation. NCBA strongly supports Secretary Rollins holding Mexico to their commitments regarding screwworm eradication.”

In November 2024, the U.S. Department of Agriculture was notified that New World screwworm was detected in Mexico. NCBA has been working closely with USDA’s Animal and Plant Health Inspection Service to increase surveillance, inspection, and other measures to counter this pest.

At the same time, NCBA has also been working with USDA to expand the use of the sterile insect technique, which requires the continuous release of sterile male screwworm files that breed with wild screwworms and result in no offspring, eradicating the species.

Unfortunately, Mexican authorities have failed to uphold their end of the agreement by disrupting planes carrying these sterile male files, refusing pilots permission to land, and instituting customs duties on flight components, sterile flies, and sterile insect technique equipment.

“We have received multiple reports that critical flights carrying these sterile flies have been denied permission to land, faced bogus paperwork issues, and been charged high customs fees. As a result, we have lost significant time and investment that has allowed these dangerous pests to spread unchecked into southern Mexico,” said NCBA Senior Vice President of Government Affairs Ethan Lane. “In light of those reports, NCBA met with the Mexican Embassy earlier this week to deliver the message that the Mexican government needs to be a partner on eradicating screwworms to protect both animal and human health. It’s time for Mexican authorities to act and we appreciate Secretary Rollins standing with American and Mexican cattle producers who want to see this pest stopped dead in its tracks.”

Earlier this week, NCBA President Wehrbein also met with senior officials at the Embassy of Mexico in Washington, D.C. to press for further action on screwworm eradication. NCBA will continue this critical work to ensure we are protecting U.S. consumers and the health of the American cattle herd.