The New World Screwworm, a parasitic fly, has been detected in Mexico and could soon enter the southeast.
The Tennessee Department of Agriculture said screwworms present a threat to pets and livestock. University of Tennessee Agriculture Extension Agent Wayne Key said screwworms lay their eggs on an animals skin, and the larvae start feeding at a young age.
“They screw into, hence the name, into the tissue, feeding on the blood and tissue of those animals,” Key said. “And they create a sore, that’s really hard, a wound, that’s really hard to control and to get it to heal.”
Screw worms are slightly larger than house flies, with orange eyes, metallic-blue or green bodies and three dark stripes on their backs. Key said there is no known way to prevent screw worm infection.
Key said you should consult the state veterinarian about any suspected infections.
“Watch for signs of discomfort or unusual behavior,” Key said. “You’ll see animals that’ll be agitated. Cows will shake their tail or move their tail. They’ll stand off by themselves for example and become isolated.”
Key said a screwworm wound could smell like rotten meat.
Key said the reason for screwworm reemergence has not been determined, but some speculate screwworms might have came north on another animal.
“Also, I’ve been reading some reports that they have began to come more northward because of our southerly wind flows,” Key said. “If you’ll notice, the last few years, we’ve had problems with, for example, fall armyworm, which is a different pest we have in our grasses, exfoliators and lawns. It’s all because the southerly flow of wind has caused those adults, the ones that lay the eggs, to be able to travel farther north.”
The USDA recently suspended live animal transport across the U.S.-Mexico border.
