A parasitic fly, the New World screwworm, has re-emerged in the United States decades after being eradicated, causing concern for cattle ranchers. The fly’s larvae infest livestock, feeding on living tissue and potentially leading to severe complications or death. While an effective treatment exists, current supplies are insufficient to meet potential demand. The re-emergence has prompted authorities to declare a disaster, initiating emergency measures to control the outbreak. The United States Department of Agriculture is working to distribute the treatment and contain the spread of the parasite. This resurgence poses a significant threat to the US cattle industry and animal welfare, requiring swift and coordinated action. Officials are investigating the origin of the re-introduction.