As cattle producers continue to monitor reports on the New World screwworm, Missouri officials recently noted an unfounded rumor the pest had reached its state.
The Missouri Department of Agriculture and the U.S. Department of Agriculture has received no such notification; the state announced in news release issued in late May. Any outlets publishing articles containing false or unfounded information were asked to remove the erroneous information immediately.
The above photo is courtesy of High Plains Journal Field Editor Kylene Scott.
What to watch for
Since this is a reportable disease of concern, there are procedures in place to investigate it, said A.J. Tarpoff, an associate professor and Extension beef veterinarian at Kansas State University.
The USDA has implemented a plan to keep the pest out of the United States, said Secretary of Agriculture Brooke Rollins. Those measures include banning imports at the border and investing in re-eradication efforts in Mexico to reduce the risk of its arriving.
The recent detections that showed up north of the control zone in southern Mexico were in Oaxaca and Veracruz, which are about 700 miles from the southern border, the Extension veterinarian said.
Proactive approach
The USDA has been proactive in controlling live animal trade at the southern border, Tarpoff said, adding it was announced May 27 that a new partnership with Mexico to renovate an existing fruit fly production facility to produce an additional 60 to 100 million sterile NWS flies weekly to help control efforts.
Rollins announced USDA is investing $21 million to renovate the production facility in Metapa, Mexico, to further the long-term goal of eradicating this insect. When operational, this facility will produce 60 to 100 million additional sterile NWS flies weekly to push the population further south in Mexico.
“I think this was a big step in keeping this pest off our doorstep,” Tarpoff said.
Extension professionals who study the economics say that stopping the spread, so it does not reach the U.S. cattle herd is essential.
David Anderson, a professor and Extension specialist in livestock and food product marketing at Texas A&M, said from a long-term perspective the cost to ranchers, livestock producers and wildlife interests if the New World screwworm reached the U.S. would be huge. Ranchers would have to do a lot more inspection and treating their cattle.
“This was often a daily activity back decades ago when we had screwworms,” Anderson said. “They would have a big impact on deer populations and be a significant hit on ranch revenue and hunting ranches.”
The sterile fly strategy is effective, but it takes time, money and a concerted effort to eradicate the New World screwworm, Anderson said.
Impact on feeders
In the short run no imports is a serious problem for feeders in the Southwest, Anderson said.
“The 1.2 to 1.3 million feeders we get a year eventually are fed in the Southwest and make up a significant percentage of annual feedyard placements,” Anderson said. “Over the last decade or so they are the equivalent of the about 18% of annual feedlot placements in Texas, Arizona and California.”
Derrell Peel, a professor in agricultural economics and Extension specialist for livestock marketing at Oklahoma State University, said Southwest feedlot operators who rely on those supplies will feel the impact the most and that will continue to grow the longer this goes on.
“People who rely on these supplies are going to be hunting around for additional supplies. That’s obviously the issue right now, is that we have extremely tight feeder cattle supplies in the United States,” Peel said. “For those folks that particularly relied on that source and were used to those cattle, it’s going to be a pretty significant impact on them and there may be more price impact regionally because of that. I don’t think, in and of itself, up to this point, that we’ve seen a lot of what you might call a national price impact from this.”
Historically the New World screwworm was endemic to both the Southeastern and Southwestern U.S., Tarpoff said.
“The successful eradication of this pest from the mainland United States in the 1950s and 60s has yielded a tremendous improvement in both economic returns as well as animal welfare,” he said. “This is a disease we don’t want back.”
Clinical signs
If a producer sees abnormal wounds heavily infested with maggots, immediately contact a local accredited veterinarian, Tarpoff said. It may lead to a call to the state animal health office and a local USDA veterinarian to help.
The fly that lays the eggs is attracted to open wounds, Tarpoff said. Common symptoms may be maggots in places like the umbilicus or castration sites of young calves or other body openings like the nose, ears or genitalia.
Animals impacted may show signs of pain such as depression, not eating and producing a pungent smell of decay from the wounds, Tarpoff said.
Any warm-blooded animal (including birds and humans) could be infected with New World screwworm maggots, he said.
“While we consider this a livestock disease, it also impacts pets and wildlife,” Tarpoff said. “In 2016, there was an outbreak in the Florida Keys that affected numerous Key deer, domestic pets as well as a raccoon.”
Current restrictions on live animal imports from Mexico remain in place, Rollins said, and as previously announced, USDA will continue to evaluate the current suspension every 30 days.
Peel believes the ban on Mexican cattle imports is likely to stay in place until later this year.
Livestock producers who want to stay up on this issue are encouraged to visit the USDA-Animal and Plant Health Inspection website that updates pertinent information, Tarpoff said. The website is https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/screwworm.
Dave Bergmeier can be reached at 620-227-1822 or [email protected].
