Mexico Races to Eradicate the Parasite Threatening Its Cattle Industry

Workers in Mexico are racing to dismantle this old plant and turn it into a new lab, meant to help the country eradicate flesh-eating screwworms. The parasite is threatening Mexico's cattle industry and raising tensions with the United States. But engineers, veterinarians and entomologists are building special labs like this one, that are designed to mimic the conditions of an animal wound, which screwworm flies seek out in order to lay their eggs. It's part of an urgent push to restart the domestic production of sterile screwworm flies, a proven method to eradicate the pest version, which burrows into the flesh of warm-blooded animals, often killing livestock if left untreated. The screwworm outbreak has strained Mexico's relationship with its biggest trading partner, the United States, which has kept its border mostly closed to Mexican cattle imports since May. On Thursday, Mexico's President Claudia Sheinbaum announced that her agriculture secretary will visit the U.S. next week, in a bid to reopen exports of livestock. The U.S. invested $21 million in this $51 million facility, but it is not expected to be open until next year. And the technique will take time, as it involves breeding millions of flies, sterilizing them with radiation and releasing them into the wild. When sterile males mate with wild females, no offspring are produced, and the population collapses over time. Mexico first used the method decades ago, successfully eradicating the screwworm in 1991 after a 19-year campaign. But the fly program coordinators say that this time, they hope to do it in far less time.