- Texas had our first con firmed case of New World Screwworm (NWS) June 3 in Zavala County. The USDA quickly relocated entomologists with the Animal & Plant Health Inspection Service (APHIS) to Kerrville who can iden- tify & confirm suspected flies or larvae quickly to begin treatment and control measures. As of June 22, there is not a case in Eastland County, and the nearest case is in Tom Green County. The USDA has developed a regularly updated site where you can keep current on the situation at https://screwworm. gov.
The NWS fly is me size of housefly or slightly tallic blue/green about the larger with large orange/ red eyes and 3 stripes from the head running length wise on its back. The female lays white eggs in or near any fresh wound, even as small as a tick bite. The hatched larvae, maggot, or screwworm can do extensive damage by feeding on living tissue. The maggots are cream to light pink colored, 1/42/3 in. long, with a tapered front & blunt rear ends and spiraled spines around the body. Both adults and larvae are temperature sensitive, being most active from 77-86 degrees and 30-70% humidity.
Check all animals as often as possible. Look for draining, enlarging, swelling, or deepening wounds, maggots, white egg masses near wounds, signs of discomfort, swelling in openings like eyes, ears, nose, and genitals, going off feed, isolating themselves from other animals or owners, and especially umbilical areas in newborn babies. A very foul odor from the wound of an infection. Livestock management procedures like castration, tagging, branding, dehorning, docking, or ear notching 2-4 months create wounds ideal for NWS. Treat any wound immediately, maintain sanitation, cover if possible and monitor daily. Use topical larvicide like coumaphos or permewounds. Use controlled is often the first indication often done within the first thrin for fly control near breeding seasons to limit calving, kidding, lambing, and farrowing during warm months. Reduce fly populations with fly tags, sprays, rubs, or foggers on animals and facilities. Keep facilities and equipment like chutes, pens, trailers, troughs, fences clean and in good repair to avoid as many injuries as possible.
