06/04/2026 | Press release | Distributed by Public on 06/04/2026 14:39
Governor Polis and the Colorado Department of Agriculture's State Veterinarian's Office announced today that Colorado is activating its New World Screwworm (NWS) response plan following the confirmed detection of NWS in Zavala County, Texas. The confirmed case involves a 3-week-old calf with an infested umbilical area, and the Texas Animal Health Commission (TAHC) is working with the U.S. Department of Agriculture to establish a robust response.
"The health and safety of our cattle, food supply, and agriculture community is vital and we urge care and vigilance for our producers around the state. Colorado is taking action to ensure readiness for the potential arrival of New World Screwworm in our state and are committed to giving the best guidance and information available to protect producers and their cattle. I have been briefed and am monitoring the situation very closely and evaluating any next steps needed," said Governor Polis.
The Colorado State Veterinarian's Office is working with the USDA and Colorado livestock industry partners to prepare for potential impacts, particularly concerning trade and interstate movement of livestock. The New World Screwworm does not pose a food safety risk, and the US food supply continues to be safe.
"Colorado has been diligently preparing for the eventuality of a New World Screwworm detection in the United States and we have a response plan ready," said Colorado State Veterinarian Dr. Maggie Baldwin. "We are working closely with our livestock industry partners to minimize the impacts of this detection on our livestock industries."
Vigilance in monitoring for myiasis is important, and early detection is key. A NWS infestation can be treated, but early detection is important to ensure animals can recover.
"Colorado's cattle industry has been actively preparing with state and federal partners for the possibility of the New World Screwworm reaching the United States. While this detection in Texas is concerning, there is no reason to panic," said Erin Karney Spaur, Executive Director of the Colorado Cattlemen's Association. "Producers should remain vigilant, monitor livestock closely, and contact their veterinarian if they observe unusual wounds or signs of infestation. The Colorado Cattlemen's Association will continue working with animal health officials and industry partners to protect animal health and support producers as the situation evolves."
Right now there is no reason for concern for private horse or livestock owners. As always, producers should continue to monitor their livestock and contact their veterinarian if they note any concerning myiasis infestations.
"The Colorado Livestock Association is in close coordination with Dr. Maggie Baldwin. We appreciate all the effort that has gone into preparing for this eventuality, and the efforts to keep our industry informed as the first US case of NWS has been reported in Texas," said Travis Grant, Chief Executive Officer for the Colorado Livestock Association. "As this situation unfolds, we are encouraging producers to remain calm and continue operating as usual while remaining vigilant about their livestock. CLA remains committed to coordinating with CDA and disseminating critical information quickly to keep producers informed."
CDA will post updates about the response on the NWS web page at ag.colorado.gov/NWS.
CDA has a NWS Emergency Response Plan, which is aligned with the USDA's NWS Response Playbook. The State Veterinarian will lead Colorado's One Health response. Key elements of Colorado's preparation include:
The USDA and Texas officials are conducting a robust response to this index case of NWS in the United States. This includes increased trapping of flies, releases of sterile NWS flies, and increased surveillance and management strategies in wildlife. You can learn more about the unified response to NWS at Screwworm.gov.
About the New World Screwworm
Screwworms are parasitic fly larvae that feed on living tissue. They are capable of causing extensive and potentially life-threatening tissue damage to affected animals. The flies are attracted to a variety of open wounds, from tick bites to wounds from procedures like dehorning, where they lay their eggs.
The fly larvae then burrow into the wounds feeding on living tissue and causing the wounds to expand and deepen. This infestation of the body of a live animal by fly larvae is called myiasis (my-EYE-a-sis).
Screwworm myiasis is a reportable condition in Colorado in animals and people. Veterinarians, producers, animal owners, and diagnostic laboratories must report any suspected case to the State Veterinarian's Office by calling 303-869-9130 or through the online Myiasis Reporting Form.