06/16/2026
New World Screwworm: What Albuquerque Cat Owners Should Know
Be Alert, Not Alarmed! In the past week several animals in Texas and New Mexico have been diagnosed with New World Screwworm (NWS).
NWS is a parasitic fly whose larvae can infest livestock, cats, dogs, and even humans. Unlike other flies that require dead tissue to grow, NWS larvae can burrow deep in healthy tissue, entering the body through moist body openings (mouth, nose, ears, ge****ls) or open wounds. Eliminating this fly from North America was an incredible international success in the early 2000s but the fly re-crossed north over the Panama Canal in 2023, reaching Mexico in 2024. The spread of NWS back into New Mexico has been expected and veterinarians in our state have been on the lookout.
Unfortunately, it is likely to be at least several years before re-eradication will be possible. We expect that this parasite will continue to spread further north and it will almost certainly reach northern New Mexico. Livestock are at greatest risk but cats and other mammals can also be affected. Cat owners should remain vigilant.
Flies can lay eggs in small wounds, even as small as a tick bite or needle stick. Cats, particularly if they have a wound, should be kept indoors and away from areas with flies whenever possible. Cats should be checked regularly for wounds and if maggots (larvae) are found they should be evaluated by a veterinarian as soon as possible so that maggots can be removed and tested.
Several medications have already received emergency use authorization from the FDA for treatment of NWS in cats including Credelio for Cats, Nexgard Combo, and nytenpyram. No products have been specifically labeled for prevention of NWS in cats but Credelio for Cats and Nexgard Combo are both likely to help. We are waiting to find out how effective selamectin (Revolution, Selarid) will be.
For more information here are some great resources:
New Mexico Department of Agriculture’s one-stop website for NWS information: https://screwwormnm.org/
Worms & Germs Blog, a leading resource for veterinary infectious disease knowledge:
https://www.wormsandgermsblog.com/2026/06/articles/diseases/parasites/new-world-screwworm-prevention-and-treatment-options-in-dogs-and-cats/
CDC NWS Outbreak updates:
https://www.cdc.gov/new-world-screwworm/situation-summary/index.html
USDA NWS Confirmed Detections map of counties:
https://www.aphis.usda.gov/animals/animal-health/livestock-and-poultry-disease/current-status/us-confirmed-cases-new-world
American Veterinary Medical Association’s NWS Resources:
https://www.avma.org/resources-tools/one-health/veterinarians-and-public-health/new-world-screwworm
Texas A&M AgriLife experts:
https://stories.tamu.edu/stories/what-is-the-new-world-screwworm-and-why-does-it-matter-to-texas/
American Kennel Club’s information for dog owners:
https://www.akcchf.org/educational-resources/library/articles/new-world-screwworm-what-dog-owners-need-to-know/
US FDA’s NWS Information for Veterinarians:
https://www.fda.gov/animal-veterinary/safety-health/new-world-screwworm-information-veterinarians
CVM is providing information to support veterinarians with the identification of animal drugs for NWS myiasis.