06/04/2026
Update on the screwworm.
⚠️Veterinary Health Alert from Dr. Henrichs!
As you may have heard, over recent months the harmful New World Screwworm has been moving even closer to our southern border. Over 26,000 cases have been reported in Mexico since the outbreak began there in late 2024. Yesterday, June 3rd, the USDA confirmed the first case in the United States in a three-week-old calf in southern Texas, 40 miles inside the US border. This may be a long way from southern Arizona, but this is a landmark event in US veterinary medicine and public health, and something all of us near the border should be aware of. New World Screwworm was eradicated from the United States in 1966, and with the exception of a small outbreak in wildlife in the Florida Keys in 2017, has been confined to Central and South America due to dedicated international cooperation between US and Central American governments, especially Panama (https://www.copeg.org/en/). New World Screwworm is unique in that these fly larvae feed on living flesh, rather than dead tissue like other maggots, causing potentially lethal tissue destruction and creating an immense public health threat. All warm-blooded animals including horses, livestock, household pets, wildlife and humans can be affected (over 2,000 cases have been reported in humans in Central America). Horses and livestock are at highest risk because they live outdoors and frequently sustain abrasions and wounds. The adult stage of the New World Screwworm can be difficult to distinguish from other species of flies.
Read more info and updates here: https://www.aphis.usda.gov/animals/animal-health/livestock-and-poultry-disease/stop-screwworm
Read more very interesting biology and identification information here:
https://extension.psu.edu/understanding-the-new-world-screwworm-biology-identification-and-prevention
Thanks, Dr.Henrichs 🦟