The New World screwworm has arrived in the United States.

For years, ranchers across Southern states have prepared for a potential invasion of the flesh-eating parasite that can wreak havoc on livestock, pets and even humans. 

Though the United States went decades without a confirmed case of the invasive pest, it’s now made its way across the U.S.-Mexico border. Officials have confirmed one case in a New Mexico dog and five cases in Texas, including cattle, a dog and a goat. 

The New World screwworm poses potentially life-threatening risks to pets, wildlife and livestock. While the risk is concentrated in a few states, experts say a massive invasion could ripple across the American economy through higher grocery prices.

Is it a fly or a worm?

Contrary to its name, the screwworm grows into an adult fly that’s about the size of a common housefly. The adult fly has orange eyes, a metallic blue or green body, and three dark stripes along the back. 

The name screwworm refers to the larvae (maggots) that burrow into open wounds, feeding as they go “like a screw being driven into wood,” according to the U.S. Department of Agriculture.

The maggots burrow into the flesh of living animals through wounds as small as a tick bite or in body openings such as the eyes or nose. That means ranchers must keep close watch over newborn calves with exposed umbilical cords and may need to rethink branding and tagging operations that could provide an entry for the pests. 

What to look for 

The screwworm can infest livestock, pets, wildlife, birds and, in rare cases, people.

Infested animals can exhibit foul-smelling wounds with visible maggots as well as lesions in navels, ears or other sites. Texas A&M says animals may bite or lick at wounds and could display unusual restlessness or lethargy. 

“Pay attention to your animals, pay attention to any wildlife that might be around your property, if they’re acting like they’re in distress,” New Mexico Livestock Board Executive Director Belinda Garland told Source New Mexico this week. “Be aware, but there’s no need to panic.”

The federal Centers for Disease Control and Prevention says people may feel or see maggots moving within a wound, or in their ears, noses, eyes or mouth. The larvae can cause painful sores that worsen within a few days. People may also experience bleeding and a foul-smelling odor from the site of the infestation. 

People should immediately see a healthcare provider, who must remove each maggot, sometimes surgically, the CDC says. 

For animals, USDA has approved emergency use of several medications for prevention and treatment of the parasite. Those include ivermectin, the drug that many people hoarded for off-label use during the coronavirus pandemic. 

Will this cost me?

The New World screwworm could raise prices at the grocery store. In fact, it probably already has: American beef prices are near record highs after ranchers liquidated herds to the smallest level in 75 years because of drought and other operating disruptions, including a halt on cattle imports from Mexico. 

In an effort to stop the screwworm, the U.S. banned live Mexican cattle imports, which traditionally occupy American pastures and feedlots before going to slaughter. Last month, David Anderson, professor and extension specialist in livestock and food product marketing at Texas A&M University, told Stateline that the move likely exacerbated meat prices. 

Beef prices have increased faster than inflation in recent months, according to the most recent consumer price index report. While ground beef prices fell 1.27% in May, that drop followed a 2.7% increase in April, CNBC reported, and beef prices remain up 12.9% year over year.

The pest could also impact dairy supplies, according to the University of California Agriculture and Natural Resources. While ranchers can hold back cattle during an outbreak, dairies may be forced to dump milk during an outbreak. 

What’s being done to stop it?

USDA has created screwworm monitoring, reporting and quarantine protocols for animals. But because the disease does not create food safety concerns, the agency will not stop any movement of animal products, including meat.

To eradicate the flies, the federal government plans to breed sterile male flies and then release them into areas with established populations. The sterilized males will mate with females, which will then lay unfertilized eggs. With females mating only once in their lifespan, officials say this method progressively reduces and eliminates the fly population.

USDA just broke ground on a $750 million sterile fly facility in Edinburg, Texas, that aims to produce up to 300 million sterile flies per week when it opens next year. The agency has also invested in sterile fly facilities in Mexico and Panama.

Political blame game

The arrival of the screwworm has ignited political attacks from Washington, D.C., to the Southern border.  

At a U.S. Senate oversight hearing earlier this week, Minnesota Democratic Sen. Amy Klobuchar raised concerns about how deep cuts to USDA employment affected the department’s ability to combat issues such as the screwworm threat. She noted that the department’s Animal and Plant Health Inspection Service lost 25% of its staff, including more than 300 veterinary services employees. 

The Trump administration has sought to deflect blame on previous President Joe Biden. 

In that same hearing, Agriculture Secretary Brooke Rollins blamed the previous administration and Mexican cartels’ “refusal to crack down” for allowing the screwworm to migrate north. 

“Everyone took their eye off the ball years ago, and unfortunately, because of the border policies, it’s coming our way,” Rollins said.

Meanwhile, Texas Agriculture Commissioner Sid Miller has called on the federal government to deploy targeted baits that kill screwworm flies before they reproduce. Miller recently lost his GOP primary for reelection.

“The science is settled. The tools are available,” Miller said in a news release this week. “What’s missing is urgency from the USDA.”

Stateline reporter Kevin Hardy can be reached at khardy@stateline.org.

Vaccine hesitancy fed by misinformation is causing new surges of measles and whooping cough, while COVID-19 hotspots persist in some states and a new threat looms from an Ebola outbreak in central Africa.  

Nationally there have been 1,983 measles cases this year, nearly the 2,288 total for all of 2025, which in itself was the worst year since 1991, the federal Centers for Disease Control and Prevention reported Friday.  

Halfway through the year, 12 states and the District of Columbia already have more measles cases than they did for a full year in 2025. That’s true for South Carolina and Utah, where cases are already more than double last year, and also for states such as Florida, which has 139 cases so far compared with eight in 2025, and Virginia, which already has 63 compared with six in all of 2025.  

South Carolina, the state with the highest number of cases this year at 669, declared an end in April to an outbreak that was the nation’s largest in 35 years. The outbreak in the northwestern part of the state was centered in Spartanburg County, where religious exemptions to vaccination have spiked.  

The Utah outbreak, which began in the Short Creek area on the Utah/Arizona border, where vaccination rates are low, has generated 484 cases this year and is now slowing, said Dr. Andrew Pavia, a pediatrician and professor at the University of Utah, speaking at a May 26 briefing for the Infectious Diseases Society of America. 

Dozens of measles patients have been hospitalized with serious symptoms such as brain inflammation or pneumonia, he said, and one baby developed life-threatening congenital measles during pregnancy but survived, he said.

The national increases signal that the U.S. will certainly lose the measles elimination status it gained in 2000, Pavia said, in a determination due this fall. 

“Most state public health departments are stretched very, very thin, limiting their ability to contain measles. Anti-vaccine rhetoric has made this all the more difficult,” Pavia said. He referred to $11 billion in federal funding cuts to local public health last year that were delayed by a restraining order when states sued. The case is in settlement negotiations, according to court records. 

The Trump administration cited a “non-existent pandemic that Americans moved on from years ago” in the funding cuts, but COVID-19 is still causing more than 1,000 deaths a month and wastewater surveillance still shows hotspots in the Appalachian region and some other states, including Michigan.

Whooping cough is also on the rise with Ohio and Florida most affected. Deaths last year were at the highest level, 22, since 2010, according to the latest CDC WONDER provisional statistics.  

“The rising number of deaths from whooping cough, including among infants, is a reminder of the vital importance of vaccination,” said Dr. Joshua Sharfstein, a pediatrician and professor at Johns Hopkins Bloomberg School of Public Health in Baltimore who follows whooping cough trends. 

“Families who follow public health guidance on vaccination and other precautions can avoid a needless tragedy,” Sharfstein said. 

Louisiana was accused of unusual delays in reporting a whooping cough outbreak last year that claimed at least two lives. Shortly after the deaths were reported, the state ended promotion of vaccines and vaccination events. At least three babies died in Kentucky last year along with at least one in Oregon. 

Unvaccinated people are like fuel for the wildfire of disease outbreaks, said Pavia, of the University of Utah, in his remarks. 

“Until we can restore faith in vaccines and restore funding for our public health agencies and increase measles vaccine coverage, we have to anticipate that there will be many more outbreaks, and some of these may blow up into very large conflagrations,” Pavia said.

Meanwhile the Trump administration announced a new quarantine center in Kenya opening Friday, May 29, for Americans exposed to the Ebola virus in the Democratic Republic of the Congo. The move was criticized by the Infectious Diseases Society of America in a statement, saying the decision to send exposed Americans to Kenya “raises serious questions about resources, timing and the level of care Americans sent there will receive.”

On Ebola, a May 22 CDC directive prohibited United States entry of non-citizens who had been in the Democratic Republic of the Congo, or nearby Uganda or South Sudan, in the previous 21 days. The disease has killed 224 people in that region, and there are more than 900 suspected cases. 

Stateline reporter Tim Henderson can be reached at thenderson@stateline.org.

WASHINGTON — Officials from the Centers for Disease Control and Prevention said Wednesday the risk of a member of the general public contracting hantavirus remains low despite several passengers on a cruise ship becoming infected with the disease. 

Dr. Brendan Jackson, an epidemiologist and the agency’s team lead in Nebraska, said Americans who were on the MV Hondius cruise ship after others were diagnosed with the illness were flown to the National Quarantine Center at the University of Nebraska Medical Center.

Healthcare providers at the site have been talking with each passenger about whether they may have been exposed to any of the people with confirmed cases. They’re also monitoring the Americans for fevers or other symptoms. 

“This particular virus has a long incubation period, so the monitoring period is 42 days,” Jackson said. “And the 42 days started with the departure of the ship, so May 11 was day one.” 

Any cruise ship passengers who traveled on commercial flights, leading to possible exposures for others on those planes, left the ship before the infections were diagnosed, he said.  

“The passengers that are being monitored who were on shared flights were separate from the passengers who were on the ship at the time the outbreak was detected. So they had actually left the ship before the outbreak was detected,” Jackson said. 

“All the passengers that were on the ship after that detection phase were transported just several days ago on a private plane directly from the Canary Islands to here in Omaha, Nebraska,” he added. 

CDC officials are working with local and state public health officials to ensure anyone who may have been exposed outside of the cruise ship isolates at home and monitors themselves for symptoms. 

The officials on the call declined to say how many people are being monitored for possible exposure or where they are located in the country, citing privacy concerns.

They also declined to talk about the two cruise ship passengers taken to Emory University Hospital’s Serious Communicable Diseases Unit in Georgia. 

Dr. David Fitter, incident manager for the agency’s hantavirus response, said that unlike the coronavirus pandemic that spread around the world in 2020, hantavirus is not new to public health officials. 

“At this moment I want to emphasize that the risk to the general public is low,” he said. 

In addition to monitoring Americans who were on the cruise ship and anyone they may have come into contact with, CDC officials have been talking frequently with lawmakers.

“We’ve held two Hill briefings and have just completed a call with the governors from the states of repatriated Americans,” Fitter said. “We’ve also held daily calls with state health officials. 

“Our role now is to continue our conversations with each passenger about their potential exposure and work with partners to ensure appropriate monitoring.”

CDC officials have encouraged the people at the Nebraska facility to stay there throughout the quarantine period but there are not currently any state or federal quarantine orders in place.

WASHINGTON — President Donald Trump on Thursday said he will nominate Erica Schwartz, who served in the president’s first administration, to lead the Centers for Disease Control and Prevention, a seat left vacant for months after his last director said she was ousted in a rift over childhood vaccines.

Trump announced his new pick on his social media platform, Truth Social, touting Schwartz’s career as a medical doctor with the U.S. armed forces.

“She is a STAR!” he wrote.

Schwartz was a deputy surgeon general during Trump’s first term, and previously served as the director of health, safety and work life while a rear admiral in the U.S. Coast Guard.

Trump’s previous CDC director, Susan Monarez, told U.S. senators under oath in September that Health and Human Services Secretary Robert F. Kennedy Jr. fired her for not agreeing to pre-approve changes to the childhood vaccine schedule, and for refusing to fire agency scientists without cause. 

Monarez held the position for just 29 days before she was ousted. She was confirmed by the U.S. Senate on a party-line vote in July.

The president also announced nominations of several other health officials to fill open spots at the CDC.

“I am also pleased to announce the appointment of Sean Slovenski as the CDC Deputy Director and Chief Operating Officer, Dr. Jennifer Shuford, MD, MPH, as the CDC Deputy Director and Chief Medical Officer, and Dr. Sara Brenner, MD, MPH, as Senior Counselor for Public Health to Secretary Robert F. Kennedy, Jr.,” Trump wrote.

“These Highly Respected Doctors of Medicine have the knowledge, experience, and TOP degrees to restore the GOLD STANDARD OF SCIENCE at the CDC, which was an absolute disaster focused on ‘mandates’ under Sleepy Joe,” he added.

The CDC’s vaccine advisory committee adjusted recommendations for childhood vaccines in September, withdrawing the agency’s recommendation that children receive the COVID-19 vaccine.