A parasitic fly whose maggots can infest living livestock, birds, pets and humans could threaten California soon.

The New World Screwworm has rapidly spread northward from Panama since 2023 and farther into Central America. As of early September, the parasitic fly was present in seven states in southern Mexico, where 720 humans have been infested and six of them have died. More than 111,000 animals also have been infested, health officials said.

In early August, a person traveling from El Salvador to Maryland was discovered to have been infested, federal officials said. But the parasitic fly has not been found in the wild within a 20-mile radius of the infested person, which includes Maryland, Virginia and the District of Columbia.

After the Maryland incident, the California Department of Public Health decided to issue a health advisory this month warning that the New World Screwworm could arrive in California from an infested traveler or animal, or from the natural travel of the flies.

Graphic images of New World Screwworm infestations show open wounds in cows, deer, pigs, chickens, horses and goats, infesting a wide swath of the body from the neck, head and mouth to the belly and legs.

The Latin species name of the fly — hominivorax — loosely translates to “maneater.”

“People have to be aware of it,” said Dr. Peter Chin-Hong, a UC San Francisco infectious diseases specialist. “As the New World Screwworm flies northward, they may start to see people at the borders — through the cattle industry — get them, too.”

Other people at higher risk include those living in rural areas where there’s an outbreak, anyone with open sores or wounds, those who are immunocompromised, the very young and very old, and people who are malnourished, the U.S. Centers for Disease Control and Prevention says.

There could be grave economic consequences should the New World Screwworm get out of hand among U.S. livestock, leading to animal deaths, decreased livestock production, and decreased availability of manure and draught animals, according to the U.S. Department of Agriculture.

“It is not only a threat to our ranching community — but it is a threat to our food supply and our national security,” the USDA said.

Already, in May, the USDA suspended imports of live cattle, horse and bison from the Mexican border because of the parasitic fly’s spread through southern Mexico.

The New World Screwworm isn’t new to the U.S.

But it was considered eradicated in the United States in 1966, and by 1996, the economic benefit of that eradication was estimated at nearly $800 million, “with an estimated $2.8 billion benefit to the wider economy,” the USDA said.

Texas suffered an outbreak in 1976. A repeat could cost the state’s livestock producers $732 million a year and the state economy $1.8 billion, the USDA said.

Historically, the New World Screwworm was a problem in the U.S. Southwest and expanded to the Southeast in the 1930s after a shipment of infested animals, the USDA said. Scientists in the 1950s discovered a technique that uses radiation to sterilize male parasitic flies.

Female flies that mate with the sterile male flies produce sterile eggs, “so they can’t propagate anymore,” Chin-Hong said. It was this technique that allowed the U.S., Mexico and Central America to eradicate the New World Screwworm by the 1960s.

But the parasitic fly has remained endemic in South America, Cuba, Haiti and the Dominican Republic.

In late August, the USDA said it would invest in new technology to try to accelerate the pace of sterile fly production. The agency also said it would build a sterile-fly production facility at Edinburg, Texas, which is close to the Mexico border, and would be able to produce up to 300 million sterile flies per week.

“This will be the only United States-based sterile fly facility and will work in tandem with facilities in Panama and Mexico to help eradicate the pest and protect American agriculture,” the USDA said.

The USDA is already releasing sterile flies in southern Mexico and Central America.

The risk to humans from the fly, particularly in the U.S., is relatively low. “We have decent nutrition; people have access to medical care,” Chin-Hong said.

But infestations can happen. Open wounds are a danger, and mucus membranes can also be infested, such as inside the nose, according to the CDC.

An infestation occurs when fly maggots infest the living flesh of warm-blooded animals, the CDC says. The flies “land on the eyes or the nose or the mouth,” Chin-Hong said, or, according to the CDC, in an opening such as the genitals or a wound as small as an insect bite. A single female fly can lay 200 to 300 eggs at a time.

When they hatch, the maggots — which are called screwworms — “have these little sharp teeth or hooks in their mouths, and they chomp away at the flesh and burrow,” Chin-Hong said. After feeding for about seven days, a maggot will fall to the ground, dig into the soil and then awaken as an adult fly.

Deaths among humans are uncommon but can happen, Chin-Hong said. Infestation should be treated as soon as possible. Symptoms can include painful skin sores or wounds that may not heal, the feeling of the larvae moving, or a foul-smelling odor, the CDC says.

Patients are treated by removal of the maggots, which need to be killed by putting them into a sealed container of concentrated ethyl or isopropyl alcohol then disposed of as biohazardous waste.

The parasitic fly has been found recently in seven Mexican states: Campeche, Chiapas, Oaxaca, Quintana Roo, Tabasco, Veracruz, and Yucatán. Officials urge travelers to keep open wounds clean and covered, avoid insect bites, and wear hats, loose-fitting long-sleeved shirts and pants, socks, and insect repellents registered by the Environmental Protection Agency as effective.

Fields of plastic, or fake turf, are spreading across the Golden State from San Diego to Del Norte counties.

Some municipalities and school districts embrace them, saying they are good for the environment and promote kids’ activity and health. But some cities, including Los Angeles, are considering banning the fields — citing concerns about children’s health and the environment.

Nowhere in the country is turf use growing faster than in California — on school athletic fields, in city parks and on residential lawns. Exact numbers are not known, but it’s estimated that 1,100 acres of the material, or the equivalent of some 870 football fields, are being installed across the state each year.

In 2025, the Laguna Beach Unified School District and the San Mateo County Office of Education both received environmental accolades from the state Department of Education for, among other efforts, installing artificial turf.

“The fields do not require water, pesticides or fertilizers. They also provide year-round playing time without the need for closures for regrowth or rain damage,” said Laura Chalkley, director of communications for San Mateo Union High School District.

But a growing number of health experts, environmentalists and parents say the fields are harming children’s health and heating up the environment — and they’re pushing their cities, counties and school districts to ban them.

Terry Saucier, a Tarzana resident and chair of the SoCal Stop Artificial Turf Task Force, wants Los Angeles to do that.

“I wish they’d stop calling it grass,” Saucier said. “It’s carpet. They’re taking green space, grass and dirt away from kids and laying down synthetic carpets.”

The L.A. City Council’s Energy and Environment Committee is studying a possible ban. It’s up for discussion in October. Other cities, including San Marino and Milbrae, already have moved to prohibit the outdoor material.

A flag football player kicks up pellets on the artificial turf at Oxnard High School.

(Michael Owen Baker / For The Times)

Turf is designed to look and feel like grass. It consists of green blades, made of nylon or other plastic polymers, rooted in a plastic mat. In between the “grass” is a layer of fine, loose material made of recycled tires, rubber, sneaker soles, sand, olive pits or coconut.

Researchers, including Sarah Evans, assistant professor of environmental medicine at the Icahn School of Medicine at Mount Sinai in New York, said a growing body of research shows these carpets have the potential to cause harm in three main ways: burns, chemical exposure and injuries.

“These surfaces get really hot,” she said, citing research that artificial turf can reach temperatures in excess of 160 degrees, and can cause first- and second-degree burns on skin. She said her own kids complain that their “feet feel like they’re burning … even with shoes on. So it’s really, really unsafe temperatures under a lot of conditions.”

Artificial turf at Oxnard High School.

(Michael Owen Baker / For The Times)

In addition, there are chemical exposures, including from forever chemicals, or PFAS, that have been detected in the blades; endocrine disruptors such as phthalates; and volatile chemicals such as benzo(a)pyrene and naphthalene. What the effects are when children and athletes play, roll and eat on the fields is not known. Studies of these and other chemicals found in crumbled tires have shown they can cause cancer in laboratory animals if inhaled, absorbed through the skin, or ingested, Evans said.

There are also injuries associated with turf fields that don’t typically occur on natural fields, including to ankles and knees, she said — the result of how cleats grip the infill.

Proponents, however, say some of those harms have not been established with certainty. And heat can be mitigated by watering the fields to keep them cool, or using natural infill products such as ground up walnut shells or olive pits that don’t heat up as much.

They also point to a draft report from California’s Office of Environmental Health Hazard Assessment that examined one part of artificial turf, the loose infill, made of recycled tires. It found “no significant health risks to players, coaches, referees and spectators from on-field or off-field exposure to field-related chemicals in crumb rubber infill from synthetic turf fields based on available data.”

Melanie Taylor, president and chief executive officer of the Synthetic Turf Council said the California report, and others, “reaffirmed the safety of turf systems, and that “in areas where natural grass is not practical or sustainable, synthetic turf ensures safe, consistent, and accessible places to play, gather, and be active.”

The report came at the request of the state’s waste agency, CalRecycle, in 2015. CalRecycle asked the health hazard assessment agency to examine tire infill as a solution to the decades-old problem of millions of tires piling up in landfills. Waste officials were looking for ways to uses the old tires and needed to know if they posed health risks to people who might recreate on the ground material.

It’s common for scientists to ask for outside review, and when the state convened an expert panel to evaluate its turf report, reviewers weren’t so sanguine about the agency’s conclusions.

Amy Kyle, one of the independent scientific advisers on the panel and a UC Berkeley environmental health scientist, said she and other advisers had concerns about several aspects of the study design and methodology — which they lodged in public discussion — but which were largely ignored.

For instance, she said, when a laboratory at UC Berkeley analyzed the chemical signatures found in the infill, it found more than 400 chemicals but could identify only roughly 180 of them.

“That fell out of the final report … or the final session of the study. Those results, they kind of left that all out,” she said.

In a transcript from one of the panel meetings in April, Kyle expressed concern about the report’s conclusions.

“It’s not an emergency. I wouldn’t evacuate playgrounds,” she told the agency and her fellow advisers. “But if I were advising my friend on the school board about this, I would say I would try not to use this stuff. “

Other panelists agreed.

“I’m glad my kid mostly played on grass,” said John Balmes, professor of medicine at UC San Francisco.

Jocelyn Claude, a staff toxicologist for the state, reiterated that the report looked only at the tire infill, and should not be seen as an official California endorsement of synthetic turf. She noted that her office did not look at the blades, where PFAS chemicals have been detected.

“Since we only looked at the crumb rubber, there are limitations in what our results state and how they can be applied,” she said.

Finally, Evans and Saucier have concerns for the wider environment: microplastics that slough off the turf and the heat generated by the fields of fossil-fuel derived plastic, which can make a local area hotter.

According to the Synthetic Turf Council, the average athletic field uses 400,000 pounds of infill and 40,000 pounds of artificial turf carpet. In addition, research shows that an average synthetic turf field loses between 2,000 and 3,000 pounds of microplastic fibers every year.

“So here, from cradle to grave, we are creating product that contributes to climate change and just makes the planet hotter,” Saucier said. Turf makers say they have made improvements to their products to lower the temperature but acknowledge they can get hot.

Elliot Copen, 17, was worried the Scouting America camp he had visited dozens of times in an undeveloped canyon of the Santa Monica Mountains would feel empty.

The Palisades fire roared down the canyon 11 months ago, destroying the historic lodge and its Hogwarts-like interior (albeit without the “flying balls,” Copen noted), a smattering of cabins and the trading post where Scouts would buy candies and memorabilia. Weeks later, heavy rains sent mud and debris careening into the canyon, burying sections of the camp in feet of dirt.

Copen, an Eagle Scout with Troop 67 in Santa Monica and a leader in the Scouts’ honor society Order of the Arrow, had seen the videos online of what the disasters had done to the camp where he had made so many memories. “It was just weird,” he said. “It felt wrong.”

On Saturday, he was one of about four dozen Scouts, parents and regional Scouting leaders that headed to camp for the first time since the fire, picked up some tools and got dirty. It was a humble and cautious start: remove some of the invasive species that were taking advantage of the open soil and dig out the camp’s veterans memorial that the mudslides had partially covered.

It was also a much-needed moment for the Scouts to mourn their loss, spend time with their peers and give back to the land that has given them so much.

Camp Josepho is one of three camps Scouting America’s Western Los Angeles County Council owns and operates. While their Catalina and Sequoia sites are certainly breathtaking, Josepho — which is just minutes from the city — was an accessible haven from the hustle and bustle of algebra tests, essay deadlines and school drama.

Since the 1940s, the 110-acre camp has served as a second home in the wild for thousands of Scouts. The land was gifted by Ganna and Anatol Josepho — a silent film star and the inventor of the photo booth, respectively. Its centerpiece was a hangar-like lodge built out of redwood by the aircraft manufacturer Donald Douglas, which is listed as a Los Angeles Historic Cultural Monument. Over the years, the camp has hosted the Scouts’ Order of the Arrow induction ceremonies, service weekends focused on projects like brush removal and many good old-fashioned camping trips.

Eagle Scout Ryan Brode, 21, with Troop 50, tries to read the fire charred plaque that lies at the foot of a hiking trail.

(Genaro Molina/Los Angeles Times)

When Copen entered the camp, he felt relieved. It was no longer the fire-stricken wasteland he saw in the videos, but in fact quite green. Yes, some of the green was invasive species, but some was made up of native grasses and shrubby chaparral plants. Many of the towering sycamore trees and elder oaks — probably far older than even the adult Scout leaders — still blot out the midday sun with new, green leaves sprouting from their charred trunks.

Noah Rottner, an Eagle Scout with Troop 777 in West Hills who is also in the Order of the Arrow, said he had hoped to “help rebuild most of the stuff that’s been burnt and get most of the memories back.” But as Rottner, 15, talked with his peers, “we were just deciding, maybe we could start new memories in it, and start a new journey.”

The Scouting council likely won’t try to reconstruct all of the camp’s facilities. Lee Harrison, 54, chief executive of the council, acknowledged that since the Palisades fire likely won’t be the last to burn through the land, a smaller footprint at the site is ultimately more sustainable.

Scouting America member Nolan Ironhill, 18, spends a moment with his thoughts while taking a breather from clearing mud from the base of a World War II Memorial.

(Genaro Molina/Los Angeles Times)

Copen fondly remembers a weekend before the fire, when his group spent the entire time at a fairly isolated campground on site. They played cards, cooked by the fire and learned how to whittle.

“When I look back on it, it brings me joy,” Copen said. “I’ll always look at the camp as a very happy place, because practically all my memories here are happy.”

More than 100 Scouting families lost their homes in the January fires, Harrison said. Scouts from the burn areas are now scattered across L.A. and beyond. The fires destroyed Scouts’ uniforms and alumni’s Eagle awards. Malibu’s Cub Scout Pack 224 lost its pinewood derby track — the testing grounds for a highly anticipated annual Scouting tradition.

But in an organization built on service and community engagement, second nature quickly kicked in.

“Leadership, citizenship — that is built into the structure of the program,” Harrison said. “Even the Scouts that lost pretty much everything, many of them went out and helped other families.”

The Scouting council replaced all of its members’ lost uniforms and awards and dished out gift cards to pay for new camping equipment. It also hosted a Catalina trip for those who lost their homes to help families take a breath and experience a few days of normalcy. One troop that was significantly affected by the fire provided counselors to help kids work through the trauma. Culver City’s Cub Scout Pack 18 hosted a pinewood derby workshop for the Malibu pack and brought its brand-new track out to a Malibu elementary school so the Scouts in that area could still experience the competition.

Aaron Kupferman, chair of Natural Resources with Camp Joseph Task Force, stands on concrete steps next to fire ravaged pine trees. The steps, which led to cabins at the camp, were the only thing that remained.

(Genaro Molina/Los Angeles Times)

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One Scout used her Eagle Scout service project to create ash sifters, which the Scouts donated to fire stations in the Palisades and Altadena to help homeowners find valuables in the rubble. Others assembled care packages for families who lost their homes.

At lunchtime, Copen admired the work his group had accomplished. Large piles of ripped-out invasive plants dotted the campground; the sunlight finally hit the memorial’s foundation, which the adults there noted they hadn’t seen in decades.

“The Scouting program and this camp makes a difference in so many people’s lives,” Copen said, with dirt smeared on his face.

“We might not have the physical structure, but this is still that camp,” Copen added. As far as he’s concerned, “that legacy is going to keep moving forward.”