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Hantavirus strikes a cruise ship, Californians at risk: Is this the start of something much worse?

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Hantavirus strikes a cruise ship, Californians at risk: Is this the start of something much worse?

The voyage was marketed for explorers eager to venture to “the edges of the map,” from Antarctica to some of the most remote islands in the world.

It would be a tantalizing trip for tourists with an appetite for adventure — less about trips to the spa and lounging by the pool than a chance to see landscapes few humans have ever laid eyes upon.

But this call of the wild was ultimately among the factors that turned the MV Hondius into the epicenter of the first-ever deadly outbreak of hantavirus aboard a modern cruise ship. Eleven cases have been linked to the outbreak so far. Three people are dead, and two others are in intensive care.

The incident — with a few uncomfortable echoes of the onset of the COVID-19 pandemic — has sparked concerns and questions. Chief among them: Was this a freak occurrence, or a sign of things to come?

“I think it’s both,” said Dr. Peter Chin-Hong, an infectious diseases expert at UC San Francisco.

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Hantavirus had previously been an obscure illness. Typically spread through exposure to infected rodents’ urine and droppings, it’s notoriously difficult to diagnose and has no specified antiviral treatment. It was definitively identified relatively recently, in a field rodent near the Hantan River in South Korea in 1978, and finally explained the mystery cause of the “Korean hemorrhagic fever” that infected thousands of United Nations troops during the Korean War.

Though rare, the disease has drawn attention in the U.S. over the decades due to its incredibly high case-fatality rate: up to 50% among the strains that circulate in the Americas.

Western Hemisphere hantavirus strains are so deadly because they can attack the lungs and make them leak. The strains that circulate in Asia and Europe — where hantavirus is more common, and generally less deadly — attack the kidneys.

Those who are severely ill can only be treated by putting them on life-support machines that directly add oxygen to their blood.

Despite its severity, the overall impact of the disease in the Americas has remained muted for two main reasons. First, most strains of hantavirus do not spread directly from person to person. And second, many people will not come into contact with rodents carrying the virus during their daily lives.

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Excursions that attract people like those aboard the MV Hondius, however, blur the second line. Launched in 2019, the ice-strengthened vessel offered passengers opportunities for “maximum contact with the nature and wildlife you traveled so far to see,” according to its operator, Oceanwide Expeditions.

“The broader pattern is definitely not random,” Chin-Hong said, “which is more expedition tourism visiting remote areas.” Climate change, he added, is also increasing the range of certain infectious diseases.

“The hantavirus in the cruise ship is unprecedented, and reflects kind of like a perfect storm of the expedition cruise through a remote area, environmental exposure potentially during a short excursion, and the hantavirus — this particular Andes virus — being capable of going from person to person,” he said.

The Andes virus, which circulates in Argentina and Chile and is mainly spread among the long-tailed pygmy rice rat, is the only hantavirus strain known to be able to transmit from human to human.

Such inter-person spread occurred previously in a deadly outbreak in Argentina. From November 2018 through February 2019, the Andes virus infected 34 people there, killing 11, according to a study in the New England Journal of Medicine.

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There were 149 passengers and staff aboard the MV Hondius when the ship publicly disclosed that three of its passengers had died. Of the 18 U.S. citizens on the ship, one passenger initially tested positive for hantavirus overseas but also got a negative test result; a follow-up test is now being done in the U.S., and results are expected in a day or so, Dr. David Fitter, incident manager for the Centers for Disease Control and Prevention’s hantavirus response, told reporters in a briefing Wednesday.

That patient, who is not ill, is being monitored at a biocontainment unit at the University of Nebraska Medical Center.

Five California residents have been potentially exposed to the virus — four aboard the cruise ship, and the fifth while on a plane with an infected person in South Africa. All five are asymptomatic and appear healthy, the California Department of Public Health said Wednesday.

Most infected people actually don’t seem to spread the Andes virus, Chin-Hong said. But some do end up being “superspreaders,” infecting others at exceptional rates.

That’s what happened in 2018-19. A single person got the Andes virus from a rodent, and the outbreak was spread mainly by three sick people who attended crowded social events, the medical journal study said — including a birthday party and a wake for one of the hantavirus victims.

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In the case of the MV Hondius, the first person believed to have contracted the hantavirus was a man from the Netherlands who was possibly exposed to rodents while bird-watching prior to boarding the ship before it left for its transatlantic journey, according to authorities. He had spent the prior three months traveling through Argentina, Chile and Uruguay, the World Health Organization said. The man boarded the ship on April 1, developed symptoms on April 6 and died on board on April 11.

“At present, the thought is that it was an ornithologist who was visiting a dump, where many rare birds congregate, and was exposed to a rodent that was in the garbage dump,” said Dr. Elizabeth Hudson, regional physician chief of infectious diseases for Kaiser Permanente Southern California.

From there, she said, the realities of cruising at sea set the stage.

“Cruise ships are a perfect environment for the spread of infectious diseases, unfortunately,” Hudson said. “You have a population of people who are living together in a relatively small and confined space, with most folks spending a good part of their time indoors eating and socializing. This means that if there’s an infection that can spread easily from person to person, the very nature of the cruise ship allows this to happen more readily.”

It can also be difficult to isolate sick people aboard a cruise ship. The MV Hondius’ doctor fell ill with hantavirus, as did another crew member who was working as a guide. Among the symptoms people reported were gastrointestinal illness, fever, general malaise, pneumonia, fatigue, aches and respiratory symptoms.

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Extensive spread of the hantavirus outbreak is not expected, health experts say. Unlike COVID-19, the Andes virus is much harder to transmit from person to person.

In past outbreaks of the Andes virus, taking steps like isolating people who are sick — and asking those who aren’t sick but have been exposed to stay away from others — have brought outbreaks to an end.

It can take up to six weeks from the time a person has been exposed to the virus to the onset of illness. That “takes us to the 21st of June,” WHO Director-General Tedros Adhanom Ghebreyesus said at a news briefing Tuesday. “WHO’s recommendation is that they should be monitored actively at a specified quarantine facility or at home for 42 days from the last exposure.”

One Californian who was on the MV Hondius, but left the ship before the hantavirus outbreak was discovered, is back home in Santa Clara County and remains healthy. That person is being asked to limit trips outside the home during the 42-day period to see if they become ill, according to Dr. Erica Pan, director of the California Department of Public Health.

Another Californian, from Sacramento County, is also back at home after sitting within a couple of seats of a hantavirus-infected passenger who was briefly on a flight from South Africa to the Netherlands before being asked to deplane due to her illness. The Californian remains healthy, but is also being asked to limit activities with others.

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“They’re not to share a bed with someone else. … They shouldn’t attend social events, and they should not visit any crowded venues,” Pan said.

Two other Californians who were on board the MV Hondius are healthy and are being observed at the University of Nebraska Medical Center’s National Quarantine Unit, the only federally funded quarantine unit in the U.S. Thirteen others are also being observed there, while two are at Emory University in Atlanta.

The California Department of Public Health said it didn’t know when the Californians in Nebraska would return home.

California health officials Wednesday said that there was a fifth state resident who was potentially exposed to the hantavirus. That person left the cruise ship, returned briefly to California, then left for additional travel, all before the outbreak was announced.

That person, who remains healthy, is now in the remote Pitcairn Islands in the south Pacific Ocean — halfway between Peru and New Zealand.

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Despite concerns surrounding this latest outbreak, the Andes virus is considered a poor candidate to become the next pandemic. One thing that makes COVID spread so easily is that people can infect others even if they’re not personally experiencing symptoms.

With COVID, people could get sick just by breathing in aerosolized viral particles floating around and pushed across an entire room by an air conditioning vent.

With the Andes virus, by contrast, people probably need to be symptomatic to spread illness.

The 2018-19 Andes virus outbreak in Argentina also showed that close contact is needed for transmission, including “being seated very close” to the sick person, Chin-Hong said.

Those at highest risk of getting hantavirus from another human have “some direct exposure to bodily fluids,” Pan said.

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The first U.S. case of Andes virus actually occurred in January 2018, in a woman who had stayed in cabins and youth hostels in the Andes region of Argentina and Chile. She did not infect anyone else after her return despite taking two commercial flights in the U.S. when sick and before she was hospitalized in Delaware. She eventually recovered at home.

More morbidly, health experts note, the Andes virus is also too deadly for it to spread rapidly in a pandemic situation.

So why are we seeing this outbreak now?

Hantavirus appears to be expanding its range in Argentina. A report published in December noted that hantavirus’ range in that country was moving southward.

“This redistribution indicates either ecological shifts affecting rodent reservoir populations, increased human encroachment into previously untouched habitats, or improved surveillance detecting cases in areas with lower historical awareness,” said the report, published by the Biothreats Emergence, Analysis and Communications Network, or BEACON, based at Boston University’s Center on Emerging Infectious Diseases.

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From mid-June through early November, there were 23 confirmed cases in the country, with nine deaths. No human-to-human transmission was reported during that time period.

Another report suggested changing temperatures and rainfall also affected hantavirus transmission in Argentina.

Another well-documented example of that phenomenon is the rise of dengue viruses in Argentina, which are spread by mosquitoes. Rising temperatures are making the climate more suitable for transmission, one study suggested.

“Climate change has definitely had an impact on Argentina,” Chin-Hong said. “As it gets warmer, you potentially have more rats.”

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Pacifica pier cracks, another coastal casualty as seas continue to rise

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Pacifica pier cracks, another coastal casualty as seas continue to rise

The Pacifica Municipal Pier was shut down and taped off Thursday after city workers noticed cracks running through the landmark structure and concrete chunks falling into the ocean.

It’s just one of many coastal California structures that have recently crumbled under pressure from a rising and relentless ocean.

Officials from the small, beach city south of San Francisco said the pier was closed due to “cracking, separation, and displacement of the concrete walkway and structural elements.”

It will stay closed while structural engineers asses its safety.

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Photos taken by city employees show a wide crack that runs from top to bottom and across the structure as well. Other photos show a large horizontal crack under the foundation of a small restaurant on the pier, the Chit Chat Cafe.

The cafe was also shut down.

This is not the first time the 53-year-old pier has shown signs of stress. In 2021, part of it was shut down after handrails along the edge collapsed. And in 2023, after a series of storms pummeled the Central California coast, damaging parts of the pier, the structure was partially closed for more than year.

Those same storms caused extensive damage in Aptos and Capitola, 70 miles south, where piers and waterfront infrastructure were swept away or damaged.

In 2024, a 150- to 180- foot section of the Santa Cruz wharf was ripped off by powerful waves.

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At least 10 of the state’s dozens of coastal public piers were closed for part or all of 2024 due to structural damage sustained in winter storms since 2022. At least five others have longer-term upgrades planned to address structural issues.

“These things are costly to maintain,” said Zach Plopper, senior environmental director at Surfrider. “They are a part of our California coastal culture in many ways, but we’re going to need to reckon with, one, the state that they’re in, and two, the continuous and worsening threats they’re going to experience,”

He said most of the piers were constructed in the early 1900s, and they weren’t built to withstand decades of rough seas, storms and rising sea level.

“With this incoming El Niño, which is forecasted to be significant, and this marine heat wave we’re in the midst of, we’re kind of in uncharted waters as far as what this winter could bring in terms of storms and swells to the California coast, and we’re likely going to see a lot more damage,” he said. “Not just piers, but roads and other coastal infrastructure up and down the state.”

There was no storm in Pacifica earlier this week, so no single event could be blamed for the destruction.

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However, a 2025 report from an outside engineering firm, GHD, found that several sections of the pier were in “poor” or “serious” condition, and they recommended closure before anticipated storms or events that could “subject the piles to high winds, swells and large waves.”

The firm found several areas of the pier where concrete was missing and rebar was exposed and corroding.

“The pier has continued to experience high winds and large waves in a harsh marine environment,” the engineers wrote in the report, noting that continuous exposure to seawater or marine spray was “detrimental” to the structure.

A 2023 city report estimated it would cost $19 million to repair.

That same year, a state law was enacted to require local governments along the California coast to plan for sea level rise in the coming decades.

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Sea level has risen some 8 inches, on average, along the coast in the past 150 years, Plopper said, and researchers anticipate another foot in the next 25 years.

“We’re going to see profound shifts on our coastline, none that we have ever experienced before, and building static structures on the coast just doesn’t work all that well,” he said. “We’re going to have to make some really hard decisions.”

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L.A. region begins the year with the smoggiest first 5 months in a decade

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L.A. region begins the year with the smoggiest first 5 months in a decade

The first five months of 2026 in Southern California have been the smoggiest — with the highest number of unhealtful air days — in more than a decade, according to statewide air monitoring.

So far this year, the South Coast air basin, which includes Los Angeles, Orange, Riverside and San Bernardino counties, has seen 39 days when the concentration of lung-irritating ozone (commonly known as smog) exceeded the federal standard, according to preliminary state air quality data.

That’s even worse than the infamously hot and hazy 2017, when Greater Los Angeles had 36 unhealthful air days by June 4 and ultimately saw 145.

Many of the roughly 18 million people who live in the air basin have been subjected to unhealthful levels of ozone, a highly corrosive gas that triggers asthma attacks and a wide range of respiratory illnesses. This has taken many by surprise since successive days of smog more commonly happen in summer, when heat waves and intense sunlight convert man-made pollution into ozone.

“If we have this many violations by this time, this could be a really awful year for air quality,” said Adrian Martinez, director of Earthjustice’s Right to Zero campaign, an initiative calling for the transition away from fossil fuels. “We’re already the worst place in the country for summertime smog pollution. So it could be one of the worst years in one of the worst places in the country.”

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The pollution has been especially severe in valleys. On April 18, an air monitor in Reseda in the San Fernando Valley measured the second highest spike in hourly ozone levels in the last decade.

Greater Los Angeles has seen more high-smog days so far in 2026 than any other year in the past decade.

(Courtesy of South Coast Air Quality Management District)

The South Coast Air Quality Management District says the high ozone levels are due to early heat waves. Officials said they were not aware of any increase in the pollutants — most of them from different kinds of exhaust — that lead to ozone formation.

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Local temperatures have been well above normal, climbing into the mid-80s and high 90s between January and April, breaking several daily high temperature records, according to the National Weather Service.

March in particular was the warmest on record in California. Riverside had an unprecedented 13 days of temperatures above 90 degrees, the weather service said.

“It was really that heat wave — conditions we typically see in July or August, we saw them in March,” said Sarah Rees, deputy executive officer of the air district. “That put us ahead of the curve in terms of how much ozone we got.”

Air district officials urged residents to monitor pollution levels on the agency’s website and mobile app, and spend only limited time outdoors when smog levels are high.

“People generally know when there’s a wildfire, because you see the smoke and smell it,” said Scott Epstein, the air district’s manager of planning and rules. “Then, it’s like, I’ve got to take precautions. Ozone, you can’t really tell.”

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Southern California has been particularly susceptible to smog formation because of its millions of gas-powered cars releasing tons of tailpipe emissions each day. The region’s sunshine acts as a catalyst for smog formation. Then the mountains trap this pollution over densely populated communities.

For nearly half a century, state and local air regulators have made rules designed to alleviate this pollution, enacting the nation’s first tailpipe emission standards in 1966 and requiring catalytic converters in 1975.

Smog-forming pollution has been dramatically reduced over the last two decades, but the region still does not meet federal air quality standards for ozone.

At an air district meeting Friday in Diamond Bar, the governing board held a moment of silence for William Burke, a former longtime chair. During his tenure, the agency enacted nearly 270 rules that are credited with reducing smog-forming pollution by hundreds of tons per day. Burke, who also founded the Los Angeles Marathon, died in May at 87.

“Those are just emission reductions,” air district Chair Michael Cacciotti said at the Friday meeting. “But what it doesn’t tell you is how many kids, families, seniors were prevented from going to the hospital from an asthma attack, didn’t get cancer or other respiratory problems.”

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Several residents from the Inland Empire, which suffers some of the worst smog pollution, expressed their appreciation for the air district’s efforts. But they also stressed the need for more progress.

“I’m old enough to remember growing up in the ‘70s and ‘80s … and not being able to see the mountains for weeks and months at a time,” said Erik Morden, one of several residents who spoke at the meeting.” I know things have improved, and I want to thank all of you for all the hard work that you’re doing. But there’s a lot of invisible stuff that you don’t see, that’s still out there — a lot of particulates in the ozone and chemicals that are causing a lot of problems.”

Martinez, the Earthjustice attorney, said the abnormally early outbreak of smog should be a wake-up call to government regulators that there’s work to be done, including offering more incentives to help residents and businesses transition to zero-emission appliances.

“We shouldn’t over-complicate it. We’ve got a lot of heat, we’ve got a lot of pollution,” Martinez said. “Our contention is, this agency can’t control the weather. But the one thing it can control is the pollution.”

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A flesh-eating worm from the 1960s is re-invading the U.S. Are CA cattle at risk?

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A flesh-eating worm from the 1960s is re-invading the U.S. Are CA cattle at risk?

Federal agricultural inspectors detected a case of New World screwworm larvae — maggots that burrow into the flesh of living animals and sometimes humans — on a 3-week-old calf in south Texas, near the U.S.-Mexico border. Officials anticipated the arrival of screwworm in the United States and say they’re prepared to contain it.

New World screwworm, also known as Cochliomyia hominivorax, is starkly different from the average maggot that feeds on decaying organic matter such as garbage, rotting food or dead animals, said Tom Talbot, veterinarian and member of the California Cattlemen’s Assn.

That’s because a screwworm larva “attacks living flesh,” Talbot said.

On Thursday, the U.S. Department of Agriculture confirmed the detection of New World screwworm in the umbilical area of a bovine in Zavala County, Texas, more than 60 miles from the northern Mexico border.

As of Friday morning, there have been no additional cases of infected animals reported.

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Screwworm is endemic in South America and parts of the Caribbean, according to the Centers for Disease Control and Prevention. However, the parasitic fly has been steadily moving north from Central America to Mexico since 2023.

The USDA says it has actively monitored the fly’s movement. Last month, the USDA was aware of more than 200 active screwworm infestation cases in the border states of Nuevo León and Tamaulipas, according to Mexico’s Secretary of Agriculture and Rural Development dashboard. There are currently more than 2,000 active cases throughout Mexico.

It was believed that the New World screwworm would enter the U.S. in 2025, “however, thanks to the hard work across the entire Trump administration and our industry, state, and local partners, we were able to buy time for this moment,” said Dudley Hoskins, undersecretary for Marketing and Regulatory Programs for the USDA, in a statement.

The potential economic impact of New World screwworm on the cattle industry due to import restrictions, reduced productivity and animal loss is substantial, said Sally DeNotta, director of the University of Florida’s Equine Performance Laboratory.

Last year, 175 key agricultural organizations signed a letter urging additional federal funding for screwworm-control measures, emphasizing USDA estimates that a New World screwworm outbreak in the U.S. could cost producers $4.3 billion annually and cause economic losses of more than $10.6 billion across the southern United States.

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“While the fly does not survive at temperatures at or below freezing, infected animals could carry the parasite northward and spread infection during the summer months, and the temperate climate of Southern California could certainly support year-round New World screwworm populations,” DeNotta said.

Talbot said from the federal to the local level, everyone in the ranching community has been talking about the arrival of screwworm and how to combat it.

“My expectation is that there will be a minimal number of cases of [New World screwworm] in California,” he said.

That’s because there are several stations on the border in Southern California, he said, that are collecting data, monitoring for any incidents of the parasitic fly and trapping them.

Talbot says he’s confident that the proactive measures on behalf of the federal government will mitigate the screwworm’s reach and therefore not impact the beef supply locally or nationally.

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How screwworm infection spreads

Female screwworm flies are attracted to the smell of wounds — that can be as small as a tick bite — and body openings such as the nose, eyes, ears and mouth where they can lay eggs, according to the CDC.

A female screwworm fly can lay 200 to 300 eggs at a time and may lay up to 3,000 eggs during her 10 to 30-day lifespan.

When the eggs hatch into maggots, the maggots eat live tissue, causing a worsening, often painful and foul-smelling wound, according to the CDC.

Screwworm has hit the United States before

There was a screwworm outbreak in the southwestern region of the United States in 1965 that prompted Mexican and U.S. livestock producers to sign a declaration to establish a joint program for the eradication of the screwworm from the states on either side of the Mexico-U.S. border, according to the National Agricultural Library.

By 1966, the United States had eradicated screwworms, but livestock remained vulnerable to reinfestation from screwworms migrating from Mexico.

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Eradication was possible through the sterile insect technique, which uses gamma radiation to irradiate screwworm pupae and create sterile male flies.

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service maintains a screwworm pupae sterilization facility in North America and is currently building a new center in southern Texas.

When produced and released in large numbers, sterile male flies mate with wild female flies, which then lay unfertilized eggs, according to the USDA.

“Since female screwworm flies normally mate only once, the population progressively reduces and is, ultimately, eradicated,” according to USDA officials.

Last year, the Trump administration cut thousands of grants and programs from the U.S. Agency for International Development, which includes U.S.-funded animal disease monitoring projects operated by the United Nations Food and Agriculture Organization, Argi-Pulse Communications reported. Among the slashed programs were some dedicated to monitoring and containing New World screwworm in Central America.

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Today, screwworm infestations aren’t a regular occurrence in the U.S., but cases have occurred in travelers returning from areas where the flies are present, according to the CDC.

Can infected animals be treated?

Infected wounds are cleaned and debrided to remove any screwworm larvae, after which the animal is treated with an approved insecticide, DeNotta said.

Last month, the U.S. Food and Drug Administration issued an emergency use authorization for several insecticides known to be effective against screwworm.

There are approved systemic and topical options for a variety of species, including cattle, horses, small ruminants, cats and dogs, DeNotta said.

“Multiple days of treatment are often required, and antibiotics and analgesics may also be administered to treat secondary infection and control pain,” she said.

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If left untreated, the tissue destruction caused by flesh-eating larvae can be extensive and severe, often resulting in debilitation and eventual death of the host, DeNotta said.

“Animals that survive may suffer weight loss, poor growth and reduced productivity as a result of pain and discomfort,” she said.

Screwworm can infect humans

Human infection is rare, DeNotta said, but it can happen.

Humans are at risk of being infected by screwworms if they travel to an area where the flies are present, such as South America and the Caribbean, according to the CDC.

CDC officials said your risk of screwworm infection increases when you:

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  • Spend a lot of time outdoors during the day, especially if sleeping or unable to keep the flies at bay.
  • Have any open wounds. A small break in the skin, including from a scratch, insect bite or recent surgery, may attract screwworm flies.
  • Have a medical condition that causes bleeding or open sores, such as from skin or sinus cancer, or from treatments that can create breaks in the skin.
  • Live, work or spend an extended amount of time with or near, livestock or other warm-blooded animals in areas where screwworm flies are present.

The symptoms humans experience when infected by screwworm

The following are symptoms of screwworm according to the CDC:

  • Feeling maggots move or seeing maggots within a skin wound, sore or body opening.
  • Painful skin wounds or sores that worsen within a few days.
  • Foul-smelling odor from the site of the infestation.
  • Bleeding from open sores.

Bacteria can also infect wounds where screwworm maggots are present and may cause an infection that can lead to symptoms like fever or chills.

To treat a screwworm infection, DeNotta said, people undergo the same combination of wound debridement and insecticides used in animals.

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