Screwworm Still South, Dairy Risks Remain

The New World screwworm has been a topic of ongoing discussion among livestock producers, and University of California Agriculture and Natural Resources scientists say it remains worth keeping top of mind. The good news is the flesh-burrowing parasite remains south of the U.S. border, though detections in Mexico underscore the need for vigilance, particularly for California’s dairy industry.

While the screwworm is not currently present in the United States, UC experts caution that California is not immune to risk. Dairy products are the state’s top agricultural commodity at $8.61 billion annually, and even brief disruptions could have major consequences. “Unlike beef cattle, which can be held back from market during a quarantine, dairy cows produce milk every day that must be processed immediately. If a farm is quarantined or a plant shuts down, milk spoils quickly and has to be dumped,” explained Daniela Bruno, UC Cooperative Extension dairy advisor for Fresno, Madera, and Kings counties.

UC ANR scientists continue to share prevention resources and monitor for early warning signs. Producers are encouraged to stay informed through official updates, including the USDA’s website, Screwworm.gov.