Mexico has reported its northernmost case of New World screwworm. The flesh-eating parasite was found in a cow less than 70 miles from the U.S.-Mexico border, according to the U.S. Department of Agriculture.
The deadly fly larva was discovered in the Mexican state of Nuevo León, which shares a small stretch of border with Texas that includes a cattle crossing.
That crossing has been closed since May to prevent the spread of the parasite. All cattle exports from Mexico to the United States have been paused intermittently since November of last year, when the parasite was discovered in a cow in southern Mexico.
The USDA says preliminary reports from Mexico’s agriculture department show the infected cow in Nuevo León had recently been moved from an area in southern Mexico with active New World screwworm cases.
Mexico’s agriculture department says the case was “immediately treated to prevent an outbreak.” The discovery of the larva in an early stage of development means there’s “no chance” of an adult fly emerging in Nuevo León, which is how the parasite spreads.
The United States eradicated the parasite in the 1960s.
