Mexican ranchers struggle to adapt as a tiny parasite ravages their cattle exports to the US

HERMOSILLO, Mexico (AP) — The United States’ suspension of live cattle imports from Mexico hit at the worst possible time for rancher Martín Ibarra Vargas, who after two years of severe drought had hoped to put his family on better footing selling his calves across the northern border.

Like his father and grandfather before him, Ibarra Vargas has raised cattle on the parched soil of Sonora, the state in northwestern Mexico that shares a long border with the United States, particularly Arizona. His family has faced punishing droughts before but has never before had to contend with the economic hit of a new scourge: the New World Screwworm, a flesh-eating parasite.

U.S. agriculture officials halted live cattle crossing the border in July – the third suspension of the past eight months — due to concerns about the flesh-eating maggot which has been found in southern Mexico and is creeping north.

The screwworm is a larva of the Cochliomyia hominivorax fly that can invade the tissues of any warm-blooded animal, including humans. The parasite enters animals’ skin, causing severe damage and lesions that can be fatal. Infected animals are a serious threat to herds.

The U.S. Department of Agriculture calls it a "devastating pest" and said in June that it poses a threat to “our livestock industry, our economy, and our food supply chain.” It has embarked on other steps to keep it out of the United States, which eradicated it decades ago.

As part of its strategy the U.S. is preparing to breed billions of sterile flies and release them in Mexico and southern Texas. The aim is for the sterile males to mate with females in the wild who then produce no offspring.

The U.S. ban on live cattle also applies to horses and bison imports. It hit a ranching sector already weakened by drought and specifically a cattle export business that generated $1.2 billion for Mexico last year. This year, Mexican ranchers have exported fewer than 200,000 head of cattle, which is less than half what they historically send in the same period.

For Ibarra Vargas, considered a comparatively small rancher by Sonora’s beef-centric standards, the inability to send his calves across the border has made him rethink everything.

The repeated bans on Mexican cows by U.S. authorities has pushed his family to branch into beekeeping, raising sheep and selling cow's milk. What he earns is just a fraction of what he earned by exporting live cattle, but he is trying to hold on through the lean times.

“Tiempos de vacas flacas" — times of the lean cows — as he calls them.

“At least it lets us continue” ranching, the 57-year-old said with a white cowboy hat perched on his head.

Even as ranchers in Sonora intensify their efforts to make sure the parasitic fly never makes it into their state, they’ve had to seek new markets.

In the past two months, they’ve sold more than 35,000 mature cows within Mexico at a significant loss.

“We couldn’t wait any longer,” said Juan Carlos Ochoa, president of the Sonora Regional Cattle Union. Those sales, he said, came at a “35% lower price difference compared with the export value of a cow.”

That’s hard to stomach when beef prices in the U.S. are rising.

The U.S. first suspended cattle imports last November. Since then, more than 2,258 cases of screwworm have been identified in Mexico. Treatment requires a mix of manually removing the maggots, healing the lesions on the cows and using anti-parasite medicine.

Some ranchers have also started retail beef sales through luxury butcher shops referred to as “meat boutiques."

There are other foreign markets, for example Japan, but selling vacuum sealed steaks across the Pacific is a dramatically different business than driving calves to U.S. feedlots. The switch is not easy.

With his calves mooing as they ran from one end of a small corral to the other waiting to be fed, Ibarra Vargas said he still hasn’t figured out how he will survive an extended period of not being able to send them to the U.S.

The recent two-year drought reduced his cattle stocks and forced him to take on debt to save the small family ranch that has survived for three generations.

Juan Carlos Anaya, director of Agricultural Markets Consulting Group, attributed a 2% drop in Mexico’s cattle inventory last year to the drought.

Anaya said Mexican ranchers who export are trying to get the U.S. to separate what happens in southern Mexico from the cattle exporting states in the north where stricter health and sanitation measures are taken, “but the damage is already done.”

“We’re running out of time,” said Ibarra Vargas, who already laments that his children are not interested in carrying on the family business. For a rancher who “doesn’t have a market or money to continue feeding his calves, it’s a question of time before he says: ‘you know what, this is as far as I go.’”

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Sánchez reported from Mexico City.

A ranch hand sprays for fly control at a ranch that supplies livestock for export to the U.S., in Zamora, northern Mexico, Tuesday, July 29, 2025, as the U.S. border remains closed to Mexican cattle imports over screwworm concerns. (AP Photo/Fernando Llano)

A worker sorts beef carcasses at an export-oriented slaughterhouse in Hermosillo, Mexico, Monday, July 28, 2025. (AP Photo/Fernando Llano)

Martín Ibarra Vargas points to his corrals at his small ranch in Hermosillo, Sonora state, Tuesday, July 29, 2025. (AP Photo/Fernando Llano)

Veterinarians examine cattle at a ranch that supplies livestock for export to the U.S., in Zamora, northern Mexico, July 28, 2025, as the U.S. border remains closed to Mexican cattle imports because of screwworm concerns. (AP Photo/Fernando Llano)

Flies of various species sit stuck in a trap near the pens of an auction in Hermosillo, Sonora state, Mexico, Tuesday, July 29, 2025. (AP Photo/Fernando Llano)

Cattle feed at a ranch that exports livestock to the U.S., in Zamora, northern Mexico, Tuesday, July 29, 2025, with the U.S. border closed to Mexican cattle imports over screwworm concerns. (AP Photo/Fernando Llano)

A ranch hand sprays for fly control at a ranch that supplies livestock for export to the U.S., in Zamora, northern Mexico, Tuesday, July 29, 2025, as the U.S. border remains closed to Mexican cattle imports over screwworm concerns. (AP Photo/Fernando Llano)

A worker sorts beef carcasses at an export-oriented slaughterhouse in Hermosillo, Mexico, Monday, July 28, 2025. (AP Photo/Fernando Llano)

Martín Ibarra Vargas points to his corrals at his small ranch in Hermosillo, Sonora state, Tuesday, July 29, 2025. (AP Photo/Fernando Llano)

Veterinarians examine cattle at a ranch that supplies livestock for export to the U.S., in Zamora, northern Mexico, July 28, 2025, as the U.S. border remains closed to Mexican cattle imports because of screwworm concerns. (AP Photo/Fernando Llano)

A calf is evaluated by a veterinary during a veterinary inspection in Hermosillo, Sonora State, Mexico, Monday, July 28, 2025. (AP Photo/Fernando Llano)

Flies of various species sit stuck in a trap near the pens of an auction in Hermosillo, Sonora state, Mexico, Tuesday, July 29, 2025. (AP Photo/Fernando Llano)

Cattle feed at a ranch that exports livestock to the U.S., in Zamora, northern Mexico, Tuesday, July 29, 2025, with the U.S. border closed to Mexican cattle imports over screwworm concerns. (AP Photo/Fernando Llano)

A ranch hand sprays for fly control at a ranch that supplies livestock for export to the U.S., in Zamora, northern Mexico, Tuesday, July 29, 2025, as the U.S. border remains closed to Mexican cattle imports over screwworm concerns. (AP Photo/Fernando Llano)

A worker sorts beef carcasses at an export-oriented slaughterhouse in Hermosillo, Mexico, Monday, July 28, 2025. (AP Photo/Fernando Llano)

Martín Ibarra Vargas points to his corrals at his small ranch in Hermosillo, Sonora state, Tuesday, July 29, 2025. (AP Photo/Fernando Llano)

Veterinarians examine cattle at a ranch that supplies livestock for export to the U.S., in Zamora, northern Mexico, July 28, 2025, as the U.S. border remains closed to Mexican cattle imports because of screwworm concerns. (AP Photo/Fernando Llano)

PROVIDENCE, R.I. (AP) — Authorities on Tuesday released a new video timeline and a slightly clearer image of the man suspected in the Brown University shooting, though investigators provided no indication that they were any closer to zeroing in on his identity.

Investigators have been canvassing Providence homes, yards and dumpsters in search of videos or other clues that might help them figure out who was behind Saturday's campus shooting, which killed two students and wounded nine others.

In all of the videos made public, the suspect's face was masked or turned away, and authorities have only been able to give a vague description of him as being stocky and about 5 feet, 8 inches (173 centimeters) tall.

The FBI also put out a video timeline that includes new footage of the man from before the attack. It shows him running at times along quiet and empty residential streets near campus. Authorities believe he was casing the area, Col. Oscar Perez, the Providence police chief, said in a news conference Tuesday.

Perez asked the public to look at their camera systems in the area to see if they have any footage that might help officials identify him.

“We’re looking for a moment that is shorter than someone taking a breath,” Perez said.

Perez said there was no clear video of the gunman from inside the engineering building where the shooting took place. Attorney General Peter Neronha said there were cameras in the newer part of the building but “fewer, if any, cameras” where the shooting happened “because it’s an older building.”

The Brown University president said the campus is equipped with 1,200 cameras.

Rhode Island Attorney General Peter Neronha said that from his perspective, the investigation was going “really well.” He pleaded for public patience in locating the suspected killer.

Providence is understandably tense, and additional police were sent to city schools on Tuesday to reassure worried parents that their kids will be safe. Ten state troopers were assigned to support the local police sent to beef up security at schools, district Superintendent Javier Montañez said.

“We recognize that the tragic incident at Brown University, occurring so close to where many of our students and families live and learn, is deeply unsettling and frightening,” he wrote in an email to parents.

Alex Torres-Perez, senior director of communications and external affairs for the Providence Public School District, said the district canceled all after-school activities and field trips for the week “as a precaution.”

Locals expressed fear as well as defiance as the investigation continued Tuesday.

“Of course it feels scary. But at the same time, I think that if the person really wanted to scare us, we shouldn’t allow him or her to win," said Tatjana Stojanovic, a Providence parent who lives next door to the Brown campus. "Despite all of that, we should just go about our lives. I mean, obviously, you cannot forget this. But I think we shouldn’t cower and just sort of stop living despite what has happened.

The attack and the shooter's escape have raised questions about campus security, including a lack of security cameras, and led to calls for better locks on campus doors.

Others pushed back, saying such efforts do little to address the real issue.

“The issue isn’t the doors, it’s the guns,” said Zoe Kass, a senior who fled the engineering building as police stormed in Saturday. “And all of this, like, ‘Oh, the doors need to be locked.’ I get it, parents are scared. But any of us could have opened the door for the guy if the doors had been locked.”

After spending of her life in schools where every door was locked and school shootings continued to persist, Kass said such security measures only created “the illusion of safety.”

FBI Boston Special Agent in Charge Ted Docks said it had 30 people in the city to support survivors, victims and loved ones, noting that the toll a tragedy like this takes on them is “immeasurable.”

Details have emerged about the victims, who were in the first-floor classroom in the school's engineering building studying for a final.

Two of the wounded students had been released as of Tuesday, Brown spokesperson Amanda McGregor said. Of the seven people that remained hospitalized, Mayor Brett Smiley said one remained in critical condition, five were in critical but stable condition and one was in stable condition.

One of the wounded students, 18-year-old freshman Spencer Yang of New York City, told the New York Times and the Brown Daily Herald that there was a mad scramble after the gunman entered the room. Many students ran toward the front, but Yang said he wound up on the ground between some seats and was shot in the leg.

Jacob Spears, 18, a freshman from Evans, Georgia, was shot in the stomach, “but through sheer adrenaline and courage, he managed to run outside, where he was aided by others," according to a GoFundMe site organized for him.

Ella Cook, a 19-year-old sophomore who was one of the two students killed, was vice president of the Brown College Republicans and was beloved in her church in Birmingham, Alabama. In announcing her death Sunday, the Rev. R. Craig Smalley described her as “an incredible grounded, faithful, bright light” who encouraged and “lifted up those around her.”

The other student killed was, MukhammadAziz Umurzokov, an 18-year-old freshman from Brandermill, Virginia, who was majoring in biochemistry and neuroscience. His family immigrated to the U.S. from Uzbekistan when he was a kid.

As a child, Umurzokov had a neurological condition that required surgery, his sister Samira Umurzokova told The Associated Press by phone. He knew from an early age that he wanted to be a neurosurgeon to help others like him.

“He had so many hardships in his life, and he got into this amazing school and tried so hard to follow through with the promise he made when was 7 years old,” she said.

Contributing were Associated Press journalists Jennifer McDermott and Matt O'Brien in Providence; Brian Slodysko in Washington; Michael Casey in Boston; Patrick Whittle in Portland, Maine; John Seewer in Toledo, Ohio; Kathy McCormack in Concord, New Hampshire; and Heather Hollingsworth in Mission, Kansas.

A Brown University student leaves campus, Tuesday, Dec. 16, 2025, after all classes, exams and papers were canceled for the rest of the Fall 2025 semester following the school shooting, in Providence, R.I. (AP Photo/Robert F. Bukaty)

Brown University students Gloria Kuzmenko-Latimir, left, and Haleema Aslam walk by Manning Hall on their way to a makeshift memorial for the shooting victims, Tuesday, Dec. 16, 2025, in Providence, R.I. (AP Photo/Robert F. Bukaty)

Visitors kneel at a makeshift memorial for the shooting victims outside the Engineering Research Center at Brown University, Tuesday, Dec. 16, 2025, in Providence, R.I.(AP Photo/Robert F. Bukaty)

Photos of Brown University shooting victims Mukhammad Aziz Umurzokov, left, and Ella Cook, are seen amongst flowers at a makeshift memorial outside the Engineering Research Center, Tuesday, Dec. 16, 2025, in Providence, R.I.(AP Photo/Robert F. Bukaty)

A memorial of flowers and signs lay outside the Barus and Holley engineering building at Brown University, on Hope Street in Providence, R.I., on Tuesday, Dec 16, 2025. (AP Photo/Matt OBrien)

Brown University senior Zoe Kass and her boyfriend return to the engineering building they fled Saturday to leave flowers on Tuesday, Dec. 16, 2025, in Providence, R.I. (AP Photo/Matt OBrien)

A classroom in Brown University's Barus and Holley building is pictured two days after a shooting occurred inside the building. in Providence, R.I., Monday, Dec. 15, 2025. (Lily Speredelozzi/The Sun Chronicle via AP)

This combo image made with photos provided by the FBI and the Providence, Rhode Island, Police Department shows a person of interest in the shooting that occurred at Brown University in Providence, R.I., Saturday, Dec. 13, 2025. (FBI/Providence Police Department via AP)

A makeshift memorial is seen on the campus of Brown University, close to from the scene of the shooting, Monday, Dec. 15, 2025, in Providence, R.I. (AP Photo/Robert F. Bukaty)

Members of the FBI Evidence Response Team search for evidence near the campus of Brown University, Monday, Dec. 15, 2025, in Providence, R.I. (AP Photo/Robert F. Bukaty)

Visitors pause at a makeshift memorial for the victims of Saturday's shooting, at the Van Wickle Gate at Brown University, Monday, Dec. 15, 2025, in Providence, R.I.(AP Photo/Robert F. Bukaty)