The U.S. Department of Agriculture confirmed the detection of a New World screwworm in a calf in Zavala County, Texas [1].
The discovery of this flesh-eating parasitic fly is a significant agricultural concern because the parasite can devastate livestock populations. Its reappearance threatens the stability of the cattle industry in regions near the Mexican border.
Officials identified the parasite in the umbilical area of a three-week-old calf [1], [4]. The USDA said that the only animal affected was this single calf in Zavala County [3]. This represents the first case of the parasite detected in the U.S. in decades [2].
According to a USDA statement, the New World screwworm was previously eradicated in the U.S. in 1966 [3], [5]. The parasite's larvae feed on the living tissue of warm-blooded animals, creating open wounds that can lead to secondary infections or death if left untreated.
USDA spokesperson Rollins said there have been no further detections [1]. The agency is monitoring the situation in South Texas to prevent a wider outbreak that could impact the regional economy and animal health.
Agricultural experts note that the proximity of the detection to the Mexican border is a critical factor in the spread of such parasites. The USDA continues to work on containment and surveillance to ensure the parasite does not establish a permanent presence in the region.
“The New World screwworm was previously eradicated in the U.S. in 1966.”
The return of the New World screwworm, even in a single isolated case, signals a potential breach in the long-standing biological barrier that has protected U.S. livestock since 1966. Because the parasite is highly invasive and destructive to livestock, the USDA must now determine if this was an isolated incident or the start of a re-infestation, which would require aggressive eradication efforts to protect the national cattle industry.
