New World Screwworm Cases Surge In Mexico - But American Cattlemen's Association Favors Imports

There's a battle along the United States' southern border, and this one's not about illegal aliens. At least, not human ones. The controversy here in cattle, specifically cattle imported into the United States from Mexico, and a fly, specifically the New World Screwworm Fly (Cochliomyia hominivorax). This fly lays eggs on animals like cattle and deer; the maggots that hatch from those eggs then burrow into the animal to feed on its flesh, causing nasty wounds that can even be fatal. The fly is native to places like Cuba, the Dominican Republic, and various places in South America, from whence it has spread into Mexico.

The two sides of the debate are already drawn up. The President of the National Cattlemen's Beef Association, or NCBA, claims that any ban on importing cattle from Mexico is not "science-based." Ranchers beg to differ. Among the agricultural organizations opposing the importations are Wyoming's Meriwether Farms, which recently took to their X account to call out the NCBA.

Here is the President of the National Cattlemen's Beef Association (NCBA) saying that shutting down livestock imports from a country that is battling an outbreak of FLESH EATING MAGGOTS is not...science-based 🤡

Mr. Woodall, did you miss the report that Mexico has had a 53%… pic.twitter.com/hoyZEfiYvK
— Meriwether Farms (@MeriwetherFarms) August 31, 2025

We should note that screwworm infestations are increasing, jumping by 53 percent in Mexico in recent months.

According to Mexican government data cited by Reuters, as of August 17 there were 5,086 recorded infestations in animals — a 53 percent increase in just one month, with 649 active cases.
The infestations, which primarily affect cattle, have also been confirmed in dogs, horses, sheep, and humans, reports BBC News. Mexican media noted that dozens of people have been treated in hospitals in the southern states of Campeche and Chiapas, and at least one elderly woman died in July when a screwworm infestation worsened an existing cancer condition.

There has been one reported human case in the United States, in a Maryland patient who had recently returned from a visit to Costa Rica.

Last spring, Agriculture Secretary Brooke Rollins blasted Mexico for not taking sufficient measures to get the infestation under control. Techniques for stamping down outbreaks of the fly can include what is essentially biological warfare, in which millions of sterilized male flies are dropped into infested areas; the sterile males mate with local females, who then bear no offspring.

Ag Sec. Brooke Rollins Threatens Mexico Cattle Imports, Puts Screws on Them to Combat Deadly Worm

But the outbreak in Mexico continues to grow worse. Complicating the problem is that the New World Screwworm Fly can also infest animals like deer and even birds, which do not recognize international borders. A halt to the importation of Mexican cattle can reduce, but not eliminate, the risk to American herds and the American people.

People have been dealing with disease outbreaks in livestock since people first started keeping livestock during the agricultural revolution. Diseases like this, spread by insects, are nothing new, and they are routinely dealt with by quarantine. This includes making efforts to contain infected areas and by not accepting livestock from infested areas into unaffected herds. In this case, it would include not accepting cattle from Mexico until a rigorous, comprehensive screening process is in place. This isn't a case for political arguments. This is a case for biology. Given the surge of cases of screwworm infestation in Mexico, it would seem that the country is behind the curve.

According to Meriwether Farms, this isn't the only controversial position the NCBA has taken.

The National Cattlemen’s Beef Association (NCBA):

-Supports amnesty for illegal ag workers
-Wants to increase foreign beef imports
-Is AGAINST Mandatory Country of Origin Labeling (MCOOL)
- Is AGAINST President Trump’s tariffs
-Takes money from corrupt BRICS-aligned meat packing… https://t.co/XHrhtiNo46
— Meriwether Farms (@MeriwetherFarms) August 31, 2025

The post continues:

-Takes money from corrupt BRICS-aligned meat packing companies
Why are these guys regularly advising the USDA Secretary and her staff?

That's a pretty good question.

The USDA has a process in place. The industry's political arm, the NCBA, thinks it's sufficient. But the people who raise cattle across the West are worried, and not without reason. This infestation in Mexico shows signs of being out of control, and it's time the USDA took a good, hard look at halting imports until Mexico gets a handle on it.