Recommended Field Protocol for the Treatment of Screwworm Myiasis and Collection of Samples for Suspected New World Screwworm (NWS)

New World Screwworm Protocol For Sample Collection and Treatment

Supplies

  • Exam or dishwashing gloves
  • Shatterproof vials with screw top or tight-fitting lids
  • 70% ethanol or isopropyl alcohol
  • Forceps or tweezers
  • Plastic tarp or garbage bags
  • Insecticide wound spray and premise treatment
  • Chlorhexidine solution
  • Other wound or NWS prevention/treatment as directed by veterinarian

Protocol

  • DO NOT transport or move livestock or wildlife from the premises.
  • If possible, take clear photos of larvae and wounds.
  • Wear gloves and cover any wounds on the person collecting samples.
  • Lay a plastic tarp or garbage bag under the wound or animal to prevent larvae from burrowing into soil.
  • Thoroughly irrigate the wound with a larvicidal liquid or spray; allow it to remain in contact for approximately five minutes.
  • Using forceps, collect multiple-sized larvae from different places within the wound.
    • Wounds may contain both NWS larvae and those of domestic blowfly species.
  • Place larvae in a shatterproof vial with 70% ethanol or isopropyl alcohol (not water or formalin).
    • Make sure the alcohol covers specimens completely.
  • Thoroughly irrigate the wound with chlorhexidine solution to eliminate bacteria, larval debris, and excreta, promoting optimal healing.
  • Dry the wound completely.
  • Apply wound ointment and/or systemic treatment as directed by a veterinarian.
  • Apply a larvicidal spray to protect the wound from reinfestation.
  • Use an insecticide or alcohol/ethanol to kill all larvae before disposal; larvae can also be burned.
  • Contact a local veterinarian, extension agent, or state animal health official to submit samples.
    • Record GPS location of the animal (see instructions below).
  • Inspect wound at least daily and retreat as needed until healed.

How to Find GPS Location

Apple Maps

  1. Open Maps.
  2. Tap the arrow/location icon to center on your current location.
  3. Touch and hold the blue dot.
  4. Swipe up on the information card.
  5. Your latitude and longitude will be displayed and can be copied.

Compass App

  1. Open the Compass app (built into most iPhones).
  2. Your latitude and longitude appear at the bottom of the screen.
  3. Copy them exactly as shown.

On Android

  1. Open Google Maps.
  2. Tap the target/location icon.
  3. Press and hold your location until a pin drops.
  4. The GPS coordinates (latitude, longitude) will appear in the search bar or information panel.
6/24/2026 1:42:16 PM
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