LANSING, Mich. (WZMQ) – Michigan has enacted new animal movement requirements effective June 17 to protect the state’s livestock, pets, and wildlife from the New World screwworm (NWS), a parasitic fly that has been detected in Texas and New Mexico.
The Michigan Department of Agriculture and Rural Development announced the restrictions Tuesday, requiring veterinary inspections for warm-blooded animals entering the state. Requirements vary based on the NWS status of the animal’s state of origin. Animals originating directly from an infested premises are prohibited from entering Michigan until that site is officially released from quarantine.
“Michigan is taking decisive action to protect the health of our livestock and pets from New World screwworm,” MDARD Director Tim Boring said. “These movement requirements are an important tool to keep this devastating pest out of our state. By staying vigilant, working closely with producers and veterinarians, and acting quickly when concerns arise, we can safeguard animal health and support the resilience of Michigan’s agriculture sector.”
No cases of NWS have been detected in Michigan. However, at least 12 confirmed cases have been found in Texas and New Mexico, affecting cattle, goats, sheep and dogs.
The screwworm is not a disease; it is a pest. The fly targets open wounds on warm-blooded animals, laying eggs that hatch into larvae that burrow into healthy tissue. The infestation is highly treatable when caught early, but can be fatal if left untreated.
“This parasitic fly poses a serious threat to the health of our livestock, pets, and wildlife when cases go unnoticed, untreated, and unreported,” said State Veterinarian Dr. Nora Wineland, DVM, MS, DACVPM. “Producers, regardless of size, and pet owners need to put eyes on their animals daily to check for things like enlarging wounds or signs of irritation. NWS starts as a parasitic worm that can enter an animal through a small break in the skin or an exposed mucous membrane, so close inspection is vital to ensure suspect cases are identified, and appropriate actions are taken to treat animals and stop the spread of the pest.”
State Sen. Ed McBroom (R-Vulcan), a dairy farmer, said the threat has been moving northward through Mexico for years and its arrival in the U.S. was widely anticipated. He drew a direct parallel to the avian influenza outbreak as a warning about how quickly animal health threats can spread across state lines.
“What we saw with avian influenza a few years ago was how much cattle are moving around the country and how quickly something like this can move. And in avian influenza, it was a few thousand cattle from Texas were suddenly on sale and they came to Michigan. And next thing you know, millions of chickens had to be either died or be put down,” McBroom said. “And I think that’s why we’re taking a more aggressive approach.”
McBroom also urged pet owners to exercise caution when traveling to affected states.
“Taking a trip to Texas suddenly with your dog, not just could be a problem for your dog, but when you come back with it, could be a problem here,” he said. “It’s going to take a lot of attention and a lot of public communication right now.”
Decades ago, the screwworm was eradicated from most of North America through a program that released sterile male flies into the population, causing females to lay infertile eggs. McBroom said efforts to rebuild that program are underway but warned it may not be enough if a major outbreak spreads across the country.
“Getting those facilities up to breed the sterile males again is taking a little time. Where some are supposed to come online again this summer, probably not going to be enough, especially if we end up having a major outbreak across the United States,” he said. “So the sooner we can get after it, the better.”
Boring said the movement restrictions will remain in effect for the duration of the heightened infestation period in Texas and New Mexico. MDARD has launched a dedicated NWS webpage at michigan.gov/screwworm, which will be updated as the situation develops.
Most poultry are exempt from the new entry requirements. Anyone who suspects an animal is infected should contact MDARD at 800-292-3939 during business hours or 517-373-0440 after hours.
