An old threat is rearing its ugly head once again, posing a huge risk to the Sunshine State, according to state officials.
In a release this month, the Florida Department of Agriculture and Consumer Services announced that the New World Screwworm (NWS) has been moving through Mexico, meaning it could be reintroduced to the U.S.
While there haven’t yet been any cases reported in the country, the agency is working with federal and regional partners to monitor the screwworm’s spread.
“The New World Screwworm — a destructive parasite that targets warm-blooded animals — was eradicated from the U.S. more than four decades ago," the release reads. “Its return would pose a serious threat to livestock, wildlife, and domestic animals, particularly in states like Florida with warm climates and abundant animal populations.”
Per experts, the NWS are maggots that often enter animals through open wounds, feeding on an animal’s living flesh. As a result, infestations can be fatal if not treated.
Experts state that screwworm eggs are deposited in a “shingle-like manner” at the edges of superficial wounds, with larvae feeding by burrowing into the wound like a screw — hence the name.
While the NWS had been present in the southwestern U.S. since at least 1842, it was first documented as a major problem in 1933 after shipments of infested animals came in from the region.
At the time, the federal government and the state of Florida began developing tactics to deal with the threat, such as education programs, special insecticides, and radiation to sterilize the insects.
But in the meantime, producers lost out on tens of millions of dollars each year as the NWS ravaged livestock, data shows.
Eventually, the U.S. and Mexico worked together to push these infestations down to the southern borders of Mexico in 1986.
There was a brief reemergence in the Florida Keys affecting the endangered Key deer back in 2016, though the outbreak was ultimately eradicated.
However, Florida officials said that infestations have been spreading north from Panama since 2023, increasing the risk of this pest being reintroduced to the U.S.
As a result, health experts are urging residents to keep an eye out for any signs of their return.
“This is about protecting American agriculture, plain and simple,” Florida Commissioner of Agriculture Wilton Simpson said. “We know how costly and dangerous this pest can be if it takes hold. We’re calling on Florida’s producers, veterinarians, and animal health professionals to remain aware and act quickly if they suspect something unusual.”
Signs of screwworm infestation in animals include the following symptoms:
- Wounds in living animals infested with maggots
- Blood-tinged discharge from the infested wounds
- Foul odor
- Discomfort
- Depressed/no eating
- Decreased milk production
- Seclusion from rest of herd or flock
If you come across a suspected case of screwworms or have questions about potential infestations, you can call the FDACS at (850) 410-0900 or click here.