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A deadly, flesh-eating parasite is threatening a resurgence in the United States and the rapid spread of infection is being blamed on the illegal cattle trade. The threat comes from the New World Screwworm (NWS), which was eradicated, at great cost, from the United States over 30 years ago.
New World Screwworms (Cochliomyia hominivorax), which are larvae or maggots of the NWS fly (pictured above), first re-appeared on the world’s health agencies’ radars in February of last year when the re-emergence of the parasite led to a national emergency in Costa Rica. Now, its presence is being felt in southern Mexico.
“Illegal cattle trade in Mesoamerica, the southern border of North America extending to the Pacific coast of Central America, follows transboundary routes starting in Nicaragua and passing through Honduras and Guatemala, before infiltrating Mexico’s food supply chain and reaching as far as the U.S. This unregulated cross-border movement has created a rapid corridor for the parasite, allowing it to travel nearly 700 miles—from the Nicaragua-Honduras border to Catazajá, Mexico—in just two and a half months,” Jeremy Radachowsky, the Wildlife Conservation Society’s Regional Director for Mesoamerica, said in November.
“This swift spread endangers millions of animals and threatens the livelihoods of ranchers across the region. By bypassing sanitary controls, often with stressed, undernourished, and injured livestock, cattle smuggling creates the ideal conditions for transboundary transmission of diseases, including brucellosis, tuberculosis, and parasites such as the screwworm,” he continued.T”he screwworm itself can infect any warm-blooded animal, including livestock, wildlife, pets, and even humans.”
Last week, the Texas Parks and Wildlife Department issued their own warning about New World Screwworms.
“Texas Parks and Wildlife Department (TPWD) asks hunters and other outdoor enthusiasts in South Texas to monitor for animals affected by New World Screwworm (NWS) after a recent detection in Mexico,” the organization wrote on Dec. 30.
“This detection, found in a cow at an inspection checkpoint in the southern Mexico State of Chiapas, close to the border with Guatemala, follows the progressively northward movement of NWS through both South and Central Americas.”
The TPWD describes the damage the New World Screwworms can cause, stating they can “cause a painful condition known as NWS myiasis.”
It occurs when New World Screwworm flies “lay eggs in open wounds or orifices of live tissue such as nostrils, eyes or mouth. These eggs hatch into dangerous parasitic larvae, and the maggots burrow or screw into flesh with sharp mouth hooks.”
Over 30 years ago, the New World Screwworm was eradicated from Central America, Mexico, and the United States at an approximate cost of $800 million.
“Time is of the essence,” Radachowsky added in his November statement. “Past unified efforts have shown we can eradicate the New World screwworm, but the window to contain this outbreak is closing rapidly. If the parasite establishes itself in Mexico, it could lead to decades of costly eradication efforts — with expenses potentially surpassing previous campaigns and largely borne by U.S. taxpayers.”