TAHC, USDA Asking Stockmen
To Be Alert For Screwworms

AUSTIN — The Texas Animal Health Commission is cautioning stockmen to keep an eye out for screwworms, the flesh-eating maggots that once cost millions of dollars in lost livestock and wildlife annually, not to mention the time and labor spent finding and doctoring "wormies."

The parasite has been officially eradicated for years, but last fall an Edwards County rancher submitted suspicious larvae from a wound in an Angora goat; one of the nine samples was identified as a screwworm.

How the insect arrived in Texas is still unknown and may never be determined.

TAHC says more than 40,000 head of livestock and dogs were inspected following the Edwards County discovery, but no further screwworms were found before cold weather put a temporary halt to the threat.

Cold weather will kill the larvae, notes USDA spokesman Gary Svetlik, but "some could have burrowed underground. If there were more larvae, and they overwintered underground, we could see an emergence of the pest this spring."

Surveillance last fall centered on Edwards and the surrounding counties of Kimble, Sutton, Val Verde, Kinney, Uvalde, Real and Kerr. This spring, however, officials are cautioning ranchers statewide to be on the alert and send in any maggots they find in animal wounds.

"We want submissions of maggots," stresses Svetlik. "If we identify another screwworm larvae, we must act quickly to eliminate the chance of the screwworm becoming re-established."

"USDA's Emergency Services is prepared to make sterile screwworm fly drops in affected areas if needed," adds TAHC executive director Dr. Terry Beals. "Anyone handling livestock, wildlife or pets should check the animals closely. If larvae or maggots are found in wounds, submit them to the screwworm lab or call us if assistance is needed."

More than 2500 screwworm submission kits have been distributed to veterinarians, feed stores and county Extension agents, and additional kits are available from TAHC area offices, TAHC headquarters at (800) 550-8242, or USDA at (512) 916-5555. The kits include a pre-printed, postage-paid mailing label and all necessary materials.

Producers without immediate access to a submission kit can preserve maggots in alcohol in a glass jar, medicine bottle or film canister. Samples should be submitted to: USDA-APHIS-VS Screwworm Lab, Moore Air Base, Bldg. 6402, Box 970, Mission, TX 78573-0970. The phone number there is (956) 580-7360.

Speed is of the essence in preventing a screwworm infestation that could undo decades of work and expose the livestock industry to losses it can no longer absorb with today's miniscule profit margins. Screwworms could also devastate the wildlife that have become such an important asset to landowners and operators who depend on hunting lease income.

Since its inception in the late 1950s, the screwworm eradication program — initiated by stockmen themselves through the Southwest Animal Health Research Foundation — has eliminated the voracious parasite first from the Southeast, then the Southwest and Mexico, and now all the way to Panama in Central America.

Production of the sterile flies that make eradication work is limited to a single plant at Tuxtla Gutierrez in Mexico's troubled state of Chiapas, leaving the program vulnerable to sabotage or even regional revolution. Should that happen in the midst of a Texas outbreak, the results could be overwhelming.

The U.S. is currently in negotiations with the government of Panama for construction of a sterile fly plant in that country, to be built by SWAHRF and leased to a joint U.S.-Panama eradication committee. The goal is to establish a screwworm barrier on the narrow Isthmus of Panama and keep screwworms out of the Northern Hemisphere indefinitely. A long-term dream of screwworm fighters is for South America to duplicate the U.S.-led program, eventually eliminating screwworms altogether.