The U.S. Department of Agriculture has confirmed a case of New World screwworm in South Texas.
The Wednesday night confirmation came hours after the USDA announced earlier in the day that there was a possible case in South Texas, with National Veterinary Services Laboratories in Ames, Iowa, working to confirm it.
According to the USDA, the detection of the parasitic fly in a 3-week-old calf in Zavala County, Texas, was confirmed, the only U.S. detection so far. Larvae were identified in the calf’s umbilical area.
In a social media post on Wednesday night, USDA Secretary Brooke Rollins said that her department is working with Texas state agencies to “contain and eradicate the pest,” reinforcing the statement that the U.S. “food supply remains 100% safe.”
This new detection — the first one since the 1960s — has forced federal and Texas agencies to work together to combat the screwworm by doing the following:
Additionally, USDA says its National Veterinary Stockpile is ready to assist and will provide resources, including treatments, equipment and logistics support, to the response as needed.
All southern U.S. ports of entry are currently closed to livestock trade, a precaution that began before the detection in Zavala County.
Zavala County sits southwest of San Antonio between the city and the border.
According to the 2020 U.S. Census, the population is 9,670.
According to the USDA, if individuals suspect their animal is infected with screwworm, contact your state animal health official or the USDA area veterinarian in charge immediately.
Texas Parks and Wildlife Department also detailed who individuals can contact for certain situations:
USDA noted that NWS maggot infestations typically affect livestock and other warm-blooded animals, with human cases being rare. The flies most often enter an animal through an open wound and feed on the animal’s living flesh.
According to the USDA, the New World screwworm (NWS) is a parasitic fly that impacts livestock, pets, wildlife, and, less commonly, people and birds. The fly’s larvae feed on the living tissue of warm-blooded animals.
USDA reports that the current risk to animals and people in the United States remains very low and that NWS is not contagious.
Rather, screwworm infestations begin when a female fly lays eggs on a wound or body opening. The eggs hatch intolarvae that burrow into the wound and feed on living tissue, then after about 7 days of feeding, larvae drop to theground, burrow into the soil, and pupate.
The adult screwworm fly emerges from the soil after 7 to 54 days.
Mateo Rosiles is the Texas Connect reporter for USA TODAY and its regional papers in Texas. Got a news tip for him? Email him at mrosiles@usatodayco.com.