Flesh-eating New World Screwworm re-occurrence in US

[Astronuc]

Deadly cattle screwworm parasite found in US patient. What to know.​

https://www.usatoday.com/story/news/health/2025/08/25/new-world-screwworm-human-case/85813010007/

The patient had recently returned to Maryland after traveling to El Salvador, Andrew G. Nixon, a spokesperson for the U.S. Department of Health and Human Services, told Reuters in an email.

On Aug. 4, the Maryland Department of Health and the Centers for Disease Control and Prevention confirmed the parasite as a New World screwworm, but said it is travel-related.

"The risk to public health in the United States from this introduction is very low," Nixon said.

While the chance of people contracting the parasite in the U.S. is low, here's what to know about the New World Screwworm.

The fly was eradicated in the U.S. in the 1960s and in Mexico in the 1970s. But Panama, Costa Rica, Nicaragua and Honduras have recently documented cases despite the parasite also being eradicated in Central America in the early 2000s.

Exclusive: U.S. confirms nation's first travel-associated human screwworm case connected to Central American outbreak​

https://www.reuters.com/business/en...ed-human-screwworm-case-connected-2025-08-25/

https://www.nbcnews.com/news/us-new...ing-screwworm-parasite-detected-us-rcna226923

https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/screwworm

New World screwworm (NWS, Cochliomyia hominivorax) is a devastating pest. When NWS fly larvae (maggots) burrow into the flesh of a living animal, they cause serious, often deadly damage to the animal. NWS can infest livestock, pets, wildlife, occasionally birds, and in rare cases, people.

 

[phyzguy]

We're building a new factory in Texas with the capability to produce 300 million sterile male screwworm flies per week. This is how we eradicated this pest before, and it should work again.

https://www.usda.gov/about-usda/new...ans-protect-united-states-new-world-screwworm

 

[elias001]

@phyzguy can this methods go beyond mere flies. I feel like the morbid Morticia from The Addams family for even suggesting/asking that.

 

[phyzguy]

What is done here is to release a huge number of sterile male flies. The females then mate with the sterile males and lay unfertilized eggs, which don't hatch. Eventually the screwworm files are all wiped out, at least in a region.

What did you want to use this technique on, besides "mere flies"? Rats? People?

 

[elias001]

@phyzguy snakes, toads, any plant based organisms that causes blight diseases.

 

[BillTre]

There are many tricks like this with insects. In this case it is helped because the insects in this case only mate once. If the male is sterile, no offspring.
I don't know of anything like this for vertebrates. They would be a lot more difficult case. Larger, slower breeding, genetics (if involved) not so easy to do.
Is blight due to a fungus?
An extension service might be a good source of information.

 

[pinball1970]

What is done here is to release a huge number of sterile male flies. The females then mate with the sterile males and lay unfertilized eggs, which don't hatch. Eventually the screwworm files are all wiped out, at least in a region.

What did you want to use this technique on, besides "mere flies"? Rats? People?

Mosquito

 

[SleipnirTheHorse]

Mosquito

Yah, know instead of trying for mosquito extinction, would could try artificially increasing their predator population, I mean dragonflies are nice!

 

[Hornbein]

On a small island the rats were wiped out with poisoned bait.

1980 medflies in California, same thing.

 

[BillTre]

Yah, know instead of trying for mosquito extinction, would could try artificially increasing their predator population, I mean dragonflies are nice!

Just common experience shows that the presence of dragonflies does not eliminate mosquitos.
Elimination of mosquitos that are vectors of nasty diseases is thegoal when it comes to disease control.