The New World Screwworm Invades Again

Will the U.S. Cattle Market Survive the Flesh Eating Pest?

Under Commodity Credit Corporation (CCC) funding, the USDA has secured $165 million dollars to help stop the spread of the deadly screwworm through Mexico and into the U.S.  Cattle imports from Mexico have been halted until further notice and the beef industry waits to see if the situation will spiral or course correct. 

Should the United States be Worried About the New World Screwworm?

While many a Texas rancher, anticipating the typical December influx of cows into the state, argues that a single case in southern Mexico is proof biological barriers are working, the Centers for Disease Control, the USDA and the North American Invasive Species Management  Association have been keeping a close eye on the spread of the deadly larvae up from Panama for three years.  A breach in the barrier one thousand miles away might not feel close to home, but it is closing in on an important food supply. 

On average the U.S. imports over a million feeder cows and sources 500 million pounds of already processed beef from Mexico every year. Even if the flesh eating worms never encounter U.S. cows, they could very well become an added pest to consumers currently purchasing beef at higher than normal prices due to drought. The year comes to an end with cattle slaughter numbers down almost 4% from last year, while the demand for beef products remains strong. Though cattle imports are not intended for slaughter the moment they cross into America, consumers could see a light increase in costs as meat companies brace for disruptions in supply chain flow. 

Over the course of a year, imported beef from Mexico accounts for 22-25% of U.S. consumption.  Ideally, business could return to normal at the start of 2025 and all of the cows and beef products intended for the United States would reach their destination, albeit later than expected.  An abrupt stop to imports aims to intentionally delay livestock moving north until additional protective barriers are put in place. The idea being that a hard stop will ultimately save time and disruption later down the road; keeping beef prices stable.

Economic Pest Control

The USDA estimates America’s livestock industry saves $900 million every year thanks to the eradication of the screwworm; an amount comprising an animal’s worth, but also time and labor costs associated with treating screwworm cases that require surgical removal of larva. In 1935 screwworms were the cause of 180,000 livestock deaths in the U.S. Ridding America of the larva cost $700 million dollars and took two decades to complete. Ranchers who remember the 1960s infestation know the cost is greater if we don’t contain the problem. Calves are among the most susceptible because they are born with an open wound at the site of the umbilical cord. 

Screwworms present yet another variable to an already pressurized market. Feeder and slaughter cattle prices have outpaced inflated pricing owing to a small U.S. herd, the result of drought conditions spanning the country. The potential for even fewer cows available in 2025 comes from both the promise of tariffs and the protocol for New World Screwworms. Cattle trade will not resume until a shift in policy and procedure is made. The question is, will it come quickly or be a drawn out process. And, when it does come, will it be with additional tariffs that drive prices up further?

If the New World Screwworm spreads across southern Mexico there would be little choice but to suspend trade indefinitely. As most of Central and parts of South America are battling the infestation themselves, with Panama having lost close to 19,000 animals and Costa Rica well over 8,000, the U.S. will have to go farther to find beef.  

Australia represents a realistic option for the United States. The two countries already have a strong cattle trade line with the U.S. purchasing more Australian beef in the middle of 2024 than what stayed in their own domestic market.  However, the gap is not likely to be filled by live animals from Australia. Imports will be primarily frozen meat cuts and manufacturing meats which will result in fewer prime cuts available in the United States. 

A screwworm infestation could cause a slight shift in exports as the U.S. hunkers down to protect their own cattle supply.  Approximately 70% of exported beef went to Japan, China and Korea.  If the U.S. opts to decrease exports then it could become a supply issue for the world. No concerted effort has been made to begin rebuilding the U.S. cattle herd, but perhaps a trade ban and tariffs will be the catalyst to begin building back.

Of course, screwworms do not just attack cows.  Hogs, sheep, horses and even humans are at risk. If there is a bright side, experts view the spread into Mexico as timely. The farther north the flies spread, the less chance they have of surviving colder temperatures. Cattle have taken the spotlight primarily because a large percentage of the U.S. herd resides in the South and Southwestern regions which are more suitable to the spread of the pests. As for now it appears that the old trick of releasing sterile male flies is being used to reverse the incursion of the flesh eating worms before it can do real damage to cattle trade.