US — Ars Technica
Flesh-eating screwworms are feasting on pets; 4 dogs and cat attacked this week
Policy1 min read
New World screwworm, a fly whose maggots eat living flesh, has spread to a third US state, Arizona. Officials have now found 74 animal cases in the US since the flies came back in June.
The pest is spreading in the US
Flesh-eating screwworm maggots have now been found in Arizona, joining New Mexico and Texas. The flies lay eggs in wounds and wet openings of animals. The young maggots eat the flesh, which can cause deep and sometimes deadly injuries. Then they drop to the ground and grow into adult flies. The article says four dogs and a cat were recently attacked.
Key numbers
- 74 animal cases identified in the US since the flies came back in June
- 3 US states affected: Texas, New Mexico, and Arizona
- 806 human cases confirmed in Mexico since the flies reemerged, according to Mexico's Ministry of Health
- 9 people in Mexico died from the maggots
How the pest was stopped before
In the 1960s, the US removed the flies by releasing sterile male flies from the air. These males mate with females, but no young are produced, so the fly population shrinks. For years, a barrier at the Darién Gap, between Panama and Colombia, kept the flies out of North America. That barrier was broken in 2022, and the flies moved north through Central America.
Why this matters
The flies harm more than farm animals. They can also hurt wildlife, pets, and, in rare cases, people. Because the pest has reached pets and is spreading across states, pet owners and farmers need to watch their animals closely for wounds.
What to watch
- Whether more US states report screwworm cases
- How many more animal and human cases are confirmed
- Whether the sterile fly release program is restarted or expanded
- Whether new barriers are built to stop the flies at the border
Glossary
- sterile male flies
- Male flies that cannot have young. Releasing many of them lowers the number of new flies.
- Darién Gap
- A rough jungle area between Panama and Colombia that was once a natural barrier against the flies.
- Ministry of Health
- The part of Mexico's government that tracks public health and disease cases.