The U.S. Department of Agriculture confirmed the detection of a New World screwworm fly in South Texas on June 3, 2024 [1, 2].
The re-emergence of this parasite poses a significant threat to the livestock industry and local wildlife. If the infestation spreads, officials said it could evolve into a billion-dollar international problem [3].
Texas state animal health officials and the USDA are working to contain the parasite. The New World screwworm is particularly destructive because its larvae feed on the living tissue of warm-blooded animals. This differs from most other fly larvae that only feed on dead tissue.
This detection marks the first USDA-confirmed case of the parasite in Texas in nearly 60 years [1]. Other reports on the duration of the fly's absence from the region vary, with some sources citing a period of 40 years [4], or more than 50 years [2].
Authorities are urging ranchers and wildlife managers to remain vigilant. The USDA is emphasizing the need for trapping and monitoring to prevent a wider outbreak. Because the screwworm can move quickly through animal populations, early detection is critical to stopping the spread.
Agricultural experts said that the cost of eradication and the potential loss of livestock make this a high-priority biological threat. The agency is coordinating with state partners to deploy traps in affected areas of South Texas to determine the extent of the infestation.
“First USDA-confirmed case of New World screwworm in Texas in nearly 60 years”
The return of the New World screwworm threatens the stability of the U.S. meat and dairy supply chain. Because the parasite attacks living tissue, it can cause rapid deterioration of livestock health and death if left untreated. A widespread outbreak would likely lead to strict quarantine measures and trade restrictions on U.S. livestock exports, creating a massive economic burden for the agricultural sector.
