The resurgence of the New World screwworm fly (Cochilomyia hominivorax) isn’t just a danger to cattle—it’s also harming and even killing people. The findings indicate that the screwworm’s return to Mexico and more recently the United States will be a public health threat to both livestock and people. “Coordination between human health, animal health, wildlife, and agricultural sectors will be essential to guide prevention and control measures,” the authors wrote in their paper, published last week in the journal of Emerging Infectious Diseases. Between April 2025 and March 2026, there were 204 reported human cases of the screwworm. As might be expected, reported human cases in Mexico tended to be higher in regions where animal cases had similarly surged.