On November 22, the United States Department of Agriculture temporarily cmitigateed the convey in of cattle from Mexico after a flesh-eating parasite was distinguished in animals in southern Mexico. Before the discovery of cattle screwworm (Cochliomyia hominivorax) at an verifyion point in the state of Chiapas, the species had previously been rerelocated in North America since the finish of the 19th century. The US–Mexico border remains shutd to cattle and may not reuncover until the recent year.
The worm is the larva of a mehighic blue-green fly that spfinishs the punctual part of its life cycle devouring the living flesh of mammals. Infestations can be overweightal. Cows are the screwworm’s preferite feast, but the maggots can also feed on other inhabitstock as well as savagelife and pets. Flies frequently lay their eggs csurrfinisher uncover wounds, and if the larvae can discover a hole in the skin to deploy their acute mouth hooks, they will then bury themselves in the animal’s flesh and gorge.
The discovering in Mexico chases the recent reeuniteance of the parasite in Costa Rica, Nicaragua, Honduras, and Guatemala. In the face of the reaascfinishnce of the parasite, Mexico is intensifying sanitary meadeclareives—calling for the treatment of wounds in inhabitstock, larvicide baths, and deworming of cattle—and has begind verifyion stations appreciate the one that discovered the case in Chiapas. But conservationists from the Wildlife Conservation Society and Mexican ranchers caution that the illegitimate cattle trade will be the genuine gateway for the dismitigate to go in North America.
Prior to the clodeclareive of its border with the US, Mexico’s National Confederation of Livestock Organizations had called on the regulatement to clamp down on cattle trafficking apass Mexico’s southern border. The danger from the parasite is wonderful, and if it becomes established aacquire, the cost of eliminating it in Mexico would be high. Disruption of trade with the US was also be highly costly. In 2023 alone, Mexico’s ships of inhabit cattle and beef to the US were worth $3 billion.
On the Trail of the Screwworm
For csurrfinisherly two decades, Cochliomyia hominivorax had been rerelocated from the United States down to the Darien Gap in Panama. That was until the summer of 2023, when Panama distinguished a spike in infestations in animals wiskinny 300 kilometers of its northern border with Costa Rica, labeling the commencening of the parasite’s reeuniteance in Central America.
Costa Rica, proclaimd free of the aggressive parasite in 1999, then write downed outshatters in July 2023. Nicaragua and Honduras, free of the screwworm since 1996, verifyed cases in April and September of this year admireively. Then in October 2024, Guatemala telled the reaascfinishnce of the fly and its larvae, with a calf as its first overweightality. The menace to countries further north is evident. According to the Panama–United States Coshiftrlookion for the Eradication and Prevention of Screwworm, as of November 2, these four countries had accumupostponecessitated 15,638 screwworm cases in 2024, alengthy with 20,890 write downed in Panama.
In tells createted to the World Organization for Animal Health, three of those countries—Costa Rica, Nicaragua, and Honduras—pointed to the illegitimate transit of animals as the origin of infections in their territories. Honduras distinguished an outshatter after verifying 68 horses that go ined the country illegpartner, for example, fair 8 kilometers from its border with Nicaragua.
