The Brief

The U.S. has confirmed its first human case of the New World screwworm, a flesh-eating parasite whose northward creep from South America has put the country's cattle industry on high alert in recent months.

The Centers for Disease Control and Prevention (CDC), in coordination with the Maryland Department of Health, confirmed the case on Aug. 4 in a patient who had returned from travel to El Salvador, Department of Health and Human Services spokesperson Andrew Nixon told NPR on Monday.

"This is the first human case of travel-associated New World screwworm myiasis (parasitic infestation of fly larvae) from an outbreak-affected country identified in the United States," Nixon said. "Currently, the risk to public health in the United States from this introduction is very low."

David McAllister, a spokesperson for the Maryland Department of Health, confirmed to NPR that the individual — a resident of Maryland — has recovered from the infection."The investigation confirmed there is no indication of transmission to any other individuals or animals," he wrote, calling the detection a "timely reminder for health care providers, livestock owners and others to maintain vigilance through routine monitoring."

The New World screwworm is a species of parasitic flies typically found in South America and the Caribbean, according to the CDC. Infestation occurs when fly larvae feed on the tissue or flesh of warm-blooded animals, primarily livestock and, rarely, humans.

"It's a fly, and it's the larvae that does the damage," says Max Scott, a professor in the Department of Entomology and Plant Pathology at North Carolina State University.

He says infestation in humans can be "quite painful," with high mortality rates if left untreated.

"Because once an infestation starts, that often attracts more flies that lay more eggs," he explains. "And depending where the wound is, the maggots can make their way into vulnerable tissue like the brain, or the wound can get quite big and then you get sepsis."

But, Scott says, screwworm is an insect, not a virus — so it's not contagious.

The pest poses a much bigger risk to livestock, and in the past year has been detected in cattle farms in Mexico. As the New World screwworm gets closer to the U.S. border, federal authorities have taken a series of steps to eliminate the threat — which they did successfully in the mid-20th century.

What exactly is New World screwworm?

An adult New World screwworm fly. They are commonly found in South America and the Caribbean.

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Denise Bonilla

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U.S. Department of Agriculture

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Screwworms are a type of blue-gray blowfly that look very similar to black flies found in the U.S.

The difference is that screwworms — specifically females — lay their eggs in live animals, usually in a wound or another entry point like a nasal cavity.

"The females can lay up to, like, 200 eggs at a time," Scott says. "And then when the eggs eat, they eat the animal alive."

After feeding, the larvae fall into the ground, burrow into the soil and emerge as adult screwworm flies, continuing the cycle.

The parasites are named after the screw-like way they burrow into tissue using their sharp mouth hooks. Their Latin name, Cochliomyia hominivorax, "literally means maneater," Scott says.

"It was named after a sort of unfortunate number of cases in the French penal colony of Devil's Island back in the 19th century," he explains.

Human cases are relatively rare these days, though counts are growing in some parts of South America.

The U.S. Embassy in Nicaragua said in July that it had confirmed 124 cases in the past year. In June, the U.S. Embassy in Costa Rica confirmed its seventh case since 2023 — and first human death "since at least the 1990s."

How was screwworm eradicated — and why is it spreading now? 

Screwworm used to be in the U.S., mainly in Florida, Texas and, during the summer, sometimes as far north as the Dakotas, Scott says.

In the 1950s, scientists with the U.S. Department of Agriculture (USDA) pioneered a method of combating them known as the sterile insect technique, which Scott calls "one of the great success stories of the USDA of the 20th century."

Instead of using broad-spectrum insecticides, they decided to use the pest itself as a control agent. That involves mass-rearing insects inside factories, sterilizing them with radiation and then releasing them — either from the ground or, as is the case today, by "planes that fly very precise routes."

"If the females on the ground mate with a sterile male, at least with a screwworm, that's all they'll mate with … so that female won't produce any offspring," Scott says.

Through this technique, the U.S. managed to eradicate New World screwworm in 1966. Mexico followed suit in the 1970s, and Central America in the early 2000s. The U.S. also used this method to eliminate what the CDC calls a "small outbreak" in the Florida Keys in 2017.

"Over a 50-year period, screwworm was pushed back from the United States through Mexico, through Central America, to the Panama-Columbia border. That was about 20 years ago," Scott says. "It was stopped at the border and then was held for a long time until the barrier broke and screwworm came back."

Panama, Costa Rica, Nicaragua and Honduras have documented new cases in recent years, fueling concerns of a northward spread.

Scott says there are probably multiple explanations, including the movement of infested cattle and the possibility that the current strain of sterilized flies is less effective than in the past. The hope, he says, is that a bigger crop of sterilized insects will be able to contain the screwworm threat to southern Mexico, before it can reach the U.S.

The corrals were empty at the Union Ganadera Chihuahua cattle import facility in Santa Teresa, New Mexico, in June, after the U.S. reinstated its pause on cattle imports across the Southern border.

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Paul Ratje

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Bloomberg via Getty Images

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What is the U.S. doing about screwworm?

The U.S. briefly halted live cattle imports from Mexico in November, after a positive case was detected there.

It lifted the ban in February but reinstated it on a month-by-month basis in May, with Agriculture Secretary Brooke Rollins citing "the continued and rapid northward spread of New World Screwworm (NWS) in Mexico." She said it had been detected in farms as far north as Oaxaca and Veracruz, some 700 miles from the U.S. border.

In the months since, the federal government has faced mounting pressure from agricultural groups worried about the threat of screwworm and its potential impact on the supply chain. In an early August letter to Rollins, they used USDA estimates to calculate that a contemporary outbreak could cause a total economic loss of more than $10.6 billion.

The USDA appears to have heard those concerns. Earlier this month, it announced sweeping plans to combat the spread of screwworm, including building the U.S.' only sterile fly production facility at an air force base in Edinburg, Texas. It says it will produce up to 300 million sterile flies per week.

Scott says at its peak, the half-century eradication campaign was run from a facility in Mexico that could produce at least 500 million sterile flies per week. It was shut down for economic reasons in 2012. There is currently only one such facility in operation, in Panama, with a maximum capacity of some 100 million flies per week.

Announcing the new initiative in Texas, Rollins did not specify when the plant will be operational, but has previously said it will take two to three years to build, Reuters reports. The USDA is also supporting a separate facility in Mexico that is slated to open in 2026.

Other steps the USDA says it will take include ramping up the hiring of USDA-employed mounted patrol officers, called "Tick Riders," to focus on border surveillance; training dogs to detect screwworm infestations in livestock at the border and investing $100 million in technologies to combat screwworm.

Agricultural groups welcomed the announcement. Zippy Duvall, president of the American Farm Bureau Federation, said in a statement that the introduction of New World screwworm in the U.S. would only exacerbate an already-volatile cattle market.

"It took decades to eradicate this parasite from within and adjacent to our borders more than a generation ago, and this is a proactive first step," he added.
Copyright 2025 NPR

After California lawmakers passed a state housing law that allows taller apartment buildings near train lines, Los Angeles leaders are facing a tradeoff: If they want to delay full implementation of the law, they’ll have to choose some parts of the city to upzone.

Gov. Gavin Newsom signed Senate Bill 79 into law last year. Starting July 1, the law is set to allow apartment buildings up to nine stories tall to be built next to subway stations and smaller buildings within a half-mile of light rail and rapid bus stops.

L.A. Mayor Karen Bass and a slim majority of the L.A. City Council had expressed opposition to SB 79, in keeping with the long-standing preference of many city leaders to leave untouched the three-quarters of L.A.’s residential land zoned for single-family homes.

Now, some L.A. leaders are scrambling to pull a delay lever that was built into SB 79. The provision allows cities to put off the law’s broadest effects until 2030, as long as they agree to allow more housing development in certain neighborhoods in the interim.

“If we don't do this, what happens is SB 79 goes into effect full-on,” said Bob Blumenfield, chair of the council’s Planning and Land Use Committee, during a meeting on Tuesday. “I really want to avoid that happening.”

Options for delay

The state law lets cities delay implementation in neighborhoods deemed to be “low resource,” in areas at high risk of fires or sea level rise or are designated as historically significant. Even with those carve-outs, some higher-income neighborhoods near train stops will still be subject to upzoning.

The city’s Planning Department produced a report last week laying out three different approaches for the City Council to delay SB 79. All of them involve local incentive programs that would allow developers to build apartment buildings in neighborhoods currently zoned for single-family homes.

The first option would allow buildings up to four stories tall, while the second and third options would permit buildings up to eight stories.

During the committee meeting Tuesday, homeowners spoke against the changes the new law would bring and the city’s upzoning plans.

“Single-family neighborhoods are where families put down roots — they are the beating heart of Los Angeles and SB 79 runs a stake right through that heart,” said Shelley Wagers with the Beverly Grove Neighborhood Association. “We must use every tool to prevent irreversible harm and buy time.”

Advocates for increased housing development said they favored the report’s third option, which would allow mid-sized apartment buildings within a half-mile of existing train stops, as well as planned stations and rapid bus stops.

Scott Epstein, policy director for Abundant Housing L.A., said that approach “offers the best opportunity to meet our housing targets and ensure that neighborhoods rich in transit services and high-quality schools are doing their part.”

What happens next

The Planning and Land Use Committee could not get a three-person majority to agree on the best path forward, so the decision will now go to the full City Council for further debate.

Blumenfield said his recommendation as committee chair was to allow mid-rise apartment buildings in many neighborhoods, but only near existing train stops, not planned stations or rapid bus stops. He also recommended more exemptions for certain historic preservation zones.

Nithya Raman, a committee member who is also running for L.A. Mayor, said she found the report’s recommendations difficult to follow. Passing a delayed implementation plan could stave off changes in some neighborhoods, but only for a while, she said.

“Eventually we will have to do something,” Raman said. “So the question is just what do we do now and what do we do later.”

But council members have little time to figure out which approach they prefer. City planners told the committee that in order to have a delay ordinance in place by July 1, the council would need to decide what direction to take by early March.

This story was originally published by The LA Local on Feb. 25, 2026.

As federal immigration enforcement raids continue across Los Angeles, a broader demographic of people is stepping up to volunteer their time to monitor and document immigration raids in their neighborhoods, according to Ron Gochez, organizer with the rapid‑response network Unión del Barrio.

“We have senior citizen retirees showing up saying, ‘I’m an old white woman — how can I help?’ We have students from community colleges and universities. We have people who look like longtime activists and people who look like they’ve never done this before,” he said. “It’s solidarity being shown by Angelenos of all shapes, sizes, colors and ages.”

While longtime Latino organizers have led the patrols, their numbers are growing thanks to the new volunteers who aren’t necessarily Latino.

Unión del Barrio has outgrown their usual meeting space at the United Teachers union building in Koreatown, which used to draw a few dozen people.

Along with their patrols, the group supports families impacted by immigration raids and issues real-time alerts over social media.

In late January, the day after federal agents shot and killed Alex Pretti in Minneapolis, about 400 people showed up for a training session, Unión del Barrio organizer Ron Gochez said.

“The very next day, we had 1,000 people on a Zoom training for educators — and we couldn’t have more because the Zoom limit was 1,000,” Gochez said.

Organizers in Pasadena expected a few dozen volunteers at All Saints Episcopal Church and were surprised when nearly 800 showed up for the training session, according to Pasadena Now.

For the first time, the majority of volunteers at a recent training session were white, Gochez said.

“I think the administration and ICE thought that by killing Alex (Pretti), that people would be scared and intimidated and would stop participating,” he said.

Instead, it has had the opposite effect.

Other immigrant advocacy groups say they’re seeing a similar surge in support. Representatives at the Coalition for Humane Immigrant Rights (CHIRLA) and the Immigrant Defenders Law Center report a spike in volunteers, donations, and attendance at “Know Your Rights” workshops.

The legal advocacy group says they’re going to continue sustaining deportation defense, managed information hotlines, and expect that engagement to remain strong as federal immigration enforcement intensifies.

Ron Gochez, a member of Unión del Barrio, speaks to volunteers in South Los Angeles in February 2025.

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Andrew Lopez

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Boyle Heights Beat

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Residents living near Koreatown and Pico Union have seen a sharp increase in immigration raids in recent months. Unión del Barrio volunteer, Oscar, who provided only his first name out of concerns over retaliation from the federal government, has seen firsthand the effects of the raids.

“This part of Los Angeles — Pico Union, K-town, MacArthur Park, Westlake — has been hit incredibly hard throughout the last year,” Oscar said, pointing to raids along the El Salvador Community Corridor in Pico Union. “They’ve gone up and down Pico multiple times.”

Westlake, a dense immigrant neighborhood predominantly made up of renters and noncitizen workers, has also been identified as one of the most vulnerable areas in L.A. to ICE raids, according to a county-sponsored study.

Oscar leads patrol training sessions, but before joining Union del Barrio, he patrolled his neighborhood with a friend to report on immigration enforcement. “It just didn’t feel like enough,” he said. “I wanted to be part of a space of dedicated organizers.”

Overall, he’s seen more people working together across racial and gender lines, with a common goal of protecting their communities, helping deliver groceries to impacted famlies, monitor their neighborhoods and feel like they have something to do in the face of the ongoing immigration raids.

Immigration agents detain a man selling flowers in Boyle Heights on Wednesday, Jan. 28, 2026.

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Courtesy of Verita Topete

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Centro CSO

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“People are coming in angry, determined,” he said. “but ultimately I think people feel empowered during the training.”

Unión del Barrio has expanded beyond its usual territory in South Los Angeles and the group now patrols in Boyle Heights, Long Beach, the San Fernando Valley, Beverly Hills and Brentwood, Gochez said.

“We have eyes and ears everywhere,” Gochez said. “I’m very comfortable saying there are thousands of people patrolling in the greater L.A. area.”

Although the group rarely solicits donations, Gochez said they have seen an uptick in funding, which helps cover costs from patrolling and printing “Know Your Rights” flyers and other materials.

Despite the heightened attention, Unión del Barrio has not altered its training curriculum, making sure that volunteers are following the law, but also aware that their safety is not guaranteed when they head out to monitor the immigration raids.

Organizers strongly discourage undocumented individuals or those on probation or parole from participating in community patrols, instead encouraging them to contribute in other ways.

“We’re not trying to become martyrs,” Gochez said. “We don’t want to be arrested, beaten or killed. But there is risk involved.”

The L.A. City Council voted unanimously Tuesday to make permanent a city pilot program that diverts police away from some mental health crisis calls.

Since launching in 2024, clinicians with the city’s Unarmed Model of Crisis Response have handled more than 17,000 calls for service, ranging from mental health crises to wellbeing checks. According to city reports, about 96% of those calls were resolved without police.

“We can’t keep deploying armed officers to handle mental health crisis calls because the outcome is Angelenos paying with loss of life and millions of their tax dollars for legal settlements,” Councilmember Eunisses Hernandez, who co-authored the motion to enshrine the program, said at Tuesday’s meeting.

According to Hernandez, in 2023, more than a third of LAPD shootings involved someone experiencing a mental health crisis.

Councilmember Marqueece Harris-Dawson said the data from city reports was "incontrovertible and unassailable," showing the program’s success at diverting police and fire first responders away from mental health crisis situations.

Council members said the move to make the unarmed model permanent was also a matter of fiscal responsibility. According to a news release from the offices of Hernandez and Councilmember Bob Blumenfield, on average it costs the city roughly $85 per hour to dispatch LAPD officers, while a response from a UMCR team costs roughly $35 per hour.

Last fall, progressive policy advocacy group LA Forward, convened a summit of local and state officials with the goal of making UMCR permanent and expanding it.

Godfrey Plata, deputy director of LA Forward, told LAist his group was “incredibly excited” to see the city make the pilot program permanent.

Plata said he sees enshrining the program as a first step in expanding the program citywide, which his group hopes to do by the 2028 Olympics.

How the program works

In 2024, the city partnered with three nonprofit organizations — Exodus Recovery, Alcott Center and Penny Lane Centers — to provide teams of trained clinicians in service areas spread across L.A. The teams are available 24 hours a day, seven days a week within the Police Department’s Devonshire, Wilshire, Southeast, West LA, Olympic and West Valley divisions.

Crisis response workers are trained in de-escalation techniques, mental health, substance use, conflict resolution and more, according to a report on the program from the Office of City Administrative Officer. The teams don’t have the authority to order psychiatric holds for people in crisis, but they can work with them to find help locally, and spend more time on follow up than law enforcement can.

In its first year, Los Angeles’s Unarmed Model of Crisis Response sent teams of unarmed clinicians to  more than 6,700 calls for service, ranging from mental health crises to wellbeing checks. Only about 4% were redirected to the LAPD. Average response times have been under 30 minutes.

Examples of these interactions include members of the teams taking food to a woman who was crying and hungry, working with a business owner to engage with someone sleeping in a parking lot and sitting with a family for nearly three hours to help resolve a conflict involving a relative.

What’s next

The motion approved Tuesday also directs city officials to form a working group made up of the LAPD, the L.A. Fire Department and other agencies to address inefficiencies in the dispatch system. The goal of the working group will be to centralize unarmed crisis response dispatch and improve response times.