Screwworm parasite sparks alarm, Mexico suspends U.S. animal imports

Mexico has temporarily halted live animal imports from the United States following the confirmation of new cases of the destructive cattle screwworm parasite. This move has triggered alarms among health and agricultural authorities in both North American countries.

The parasite, scientifically known as Cochliomyia hominivorax, is a type of fly whose larvae infest the flesh of warm-blooded animals, including livestock and, in rare instances, humans. If left untreated, the infestation can cause severe tissue damage, infections, and potentially death.

Mexico's Ministry of Agriculture and Rural Development announced the import suspension to protect its livestock, particularly in northwestern states where the parasite has not yet been detected. The ban covers cattle, sheep, goats, pigs, horses, and other animals intended for breeding, work, sport, or slaughter. Certain birds and even ferrets are also included in the restrictions.

The re-emergence of the screwworm is particularly concerning because North America had largely eradicated it through successful biological control campaigns, notably the sterile insect technique, implemented from the 1950s to the 1980s. The recent confirmation of five cases in the southern United States, three in Texas and one in New Mexico, suggests the parasite is spreading beyond a single region.

While live animal imports are suspended, authorities have agreed to enhance health checks and require additional health certificates for pet dogs crossing the border to mitigate transmission risks. The situation underscores the ongoing challenges in maintaining pest-free status and the potential economic impact on the livestock industry.