June 8, 2026

Dear Veterinary Colleagues,

The California Department of Food and Agriculture (CDFA) is providing the following information to California veterinarians regarding the recent detection of  New World Screwworm (NWS) in Texas.

On June 3, 2026, the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the presence of NWS in Zavala County, Texas. The affected animal is a 3-week-old calf, and larvae were identified in its umbilical area. Since then, three more cases have been identified in Texas, one each in Zavala, La Salle, and Andrews counties. These are the first confirmed detections of NWS in animals in the continental United States since eradication.

New World Screwworm is a reportable foreign animal disease. NWS larvae can infest any warm-blooded animal, including companion animals, equids, livestock, wildlife, and rarely avian species and people. Infestations may progress rapidly as the larvae (maggots) feed on living tissue. Early recognition, prompt reporting, and appropriate sample collection are critical to support rapid identification and response.

In response to the confirmations in Texas, CDFA is implementing additional import requirements, enhancing monitoring at California Border Protection Stations, and increasing outreach to veterinarians, animal health partners, and stakeholders. Updated import requirements from NWS areas can be found CDFA - AHFSS - New World Screwworm.

Veterinarians are requested to take the following actions:

• Increase vigilance for wounds, lesions, or myiasis consistent with NWS, particularly in animals that have recently traveled from Texas, Mexico, or other NWS-infested zones.
• Thoroughly examine wounds and body orifices where infestations may occur, including the ears, eyes, oral and nasal cavities, genital region, umbilical areas in neonates, and any small wounds.
• Immediately report suspected cases to CDFA before treating an animal.
• If larvae are collected, place specimens in a leak-proof container with 70% ethanol or isopropyl alcohol. CDFA will provide additional instructions for submission for confirmatory identification by the National Veterinary Services Laboratories (NVSL).
• After sample collection, provide appropriate clinical care as indicated, including wound management, removal of larvae, and treatment with products effective against NWS.
• Advise clients traveling with companion animals to look out for wounds, maggots, fly eggs, or signs of discomfort, particularly after travel to or from areas where NWS is present.

CDFA and USDA will continue to provide updates as additional information becomes available.

Stay Informed

For additional information, please visit:

CDFA New World Screwworm

https://www.cdfa.ca.gov/AHFSS/Animal_Health/screwworm/

USDA APHIS Screwworm

www.screwworm.gov

Contact us if you have any questions, suspicious cases, or want to request outreach:

• CDFA Sick Animal Hotline: 866-922-2473
• Email:NWSinfo@cdfa.ca.gov
• CDFA District Veterinarian Contacts

We appreciate your ongoing partnership with the California Department of Food and Agriculture and your vigilance for diseases of regulatory concern for the protection of the people and animals of California. CDFA is in the process of implementing import requirements, enhancing border crossing monitoring, and increasing our outreach and stakeholder engagement.

Thank you for all you do to help keep California’s animals, people, and agriculture safe and healthy.

Sincerely,

Dr. Mandy Murray, DVM, MPVM, PhD

Acting State Veterinarian

Animal Health Branch Chief

Attachments:

1. NWS Fact Sheet
2. NWS Identification Table