德州牧场主正担心「新世界螺旋蛆」（screwworm）在北墨西哥回潮后重返美国。60岁的牧场主兼兽医克里斯・沃麦克回忆1970年代亲眼见到小牛被蛆虫侵蚀的惨烈景象，如今他认为同业可能得再次面对这种能在不到两周内致死牛只的寄生害虫。

螺旋蛆会在温血动物的伤口或黏膜产卵，幼虫孵化后钻入肉里造成巨大溃烂；不只侵袭家畜与野生动物，也可能感染犬猫甚至人。虽然可治疗，但若在美国重新建立族群，牧场必须频繁巡检、寻找躲进灌木的病畜并立即处置；在牧场面积辽阔、人力吃紧的德州，这将成为沉重负担，也暴露出年轻从业者缺乏经验的「世代性陌生」。

疫情与防堵也牵动经济与供应链：美国牛群处于低点且成本上升，螺旋蛆风险使美方对墨西哥牛只进口长期受限，正值牛肉价格高涨之际更添压力。农业部估计一旦爆发，德州生产者可能损失7.32亿美元、州经济受创18亿美元；州内仍有约1,210万头牛，约占全美14%，因此地方官员已宣布灾害状态并预期此议题将多年优先处理。

Texas ranchers are bracing for the possible return of the New World screwworm, a flesh-eating pest once driven out of the US but now spreading again in northern Mexico near the Texas border. Veteran rancher and veterinarian Chris Womack, who fought the parasite as a teenager in the 1970s, says the industry may have to relearn grim, labor-intensive practices to protect herds if the insect reestablishes itself.

Screwworm flies lay eggs in open wounds or membranes; the hatched larvae burrow into living tissue, creating large, maggot-filled lesions. While treatable, the practical challenge is detection and rapid intervention across vast ranches where labor is scarce and sick animals can hide in brush—compounded by a generational gap in firsthand experience among younger producers and veterinarians.

The resurgence threatens an already strained US cattle sector facing a historically small herd and higher costs, and it has also driven long-running restrictions on cattle imports from Mexico. Sterile-insect releases—an approach dating to the 1960s—have begun along the Texas border, but full eradication requires fly-production capacity that no longer exists at prior scale; plans include major investments to rebuild North American output over the coming years, underscoring the risk to livestock, wildlife, and rural economies if the pest returns. (Key numbers: 7.32, 18, 1,210, 14)