The first equine case of New World screwworm in the United States this century has been confirmed in a working ranch horse in West Texas, adding a new concern for horse owners as animal health officials continue efforts to contain the parasite.
The case was detected Sept. 9 on the hind limb of a ranch horse in Presidio County, according to U.S. Equestrian. USDA data also confirmed the case, Reuters reported.
New World screwworm larvae feed on the living tissue of warm-blooded animals, making even relatively small wounds potential sites for infestation. Horses, cattle, wildlife, pets and people can be affected.
The equine case comes amid the parasite’s return to the United States after it was eradicated from the country in the 1960s. Reuters reported that the earlier outbreak killed thousands of animals before eradication was achieved.
Movement restrictions follow Texas case
The Texas Animal Health Commission has restricted the movement of warm-blooded animals outside a designated infested zone in portions of Presidio and Jeff Davis counties following detection of the horse case, according to Reuters.
The origin of the horse’s infestation has not been publicly identified. Reuters reported that USDA and Texas authorities had not addressed how the working ranch horse became infected.
The detection is particularly significant for the equine industry because horses frequently travel between ranches, competitions, breeding facilities and other events.
US Equestrian said it has protocols in place for licensed competitions intended to reduce opportunities for the fly to spread. Depending on the situation, those measures can include inspecting horses for wounds upon arrival and continuing to monitor them throughout a competition.
State animal health officials may also establish requirements for horses entering from states or geographic areas where screwworm cases have been identified.
Horse owners urged to check wounds daily
US Equestrian is urging owners to inspect horses every day, paying particular attention to wounds, swelling, drainage, foul odors or visible maggots.
Small cuts and surgical sites should be monitored, along with the umbilical area of foals and moist areas around the lips, nostrils, eyes and genitalia.
If maggots or other unusual signs are found in a wound, owners should contact a veterinarian immediately. Rapid identification and reporting can allow animal health officials to respond with eradication measures, including sterile fly releases.
“We encourage every horse owner to help protect their horses and the broader equine community by practicing good wound care, fly control, and biosecurity,” US Equestrian said.
US Equestrian also recommends keeping wounds clean and covered as directed by a veterinarian, using veterinarian-recommended fly control and reducing flies’ access to horses through measures such as fly masks, sheets and clean stabling practices.
The organization has also established screwworm guidance for competition organizers and participants as officials work to prevent infestations and the quarantines that could follow them.