Illegal Cattle Trafficking Is Fueling Dangerous Resurgence of New World Screwworm

The New World screwworm (Cochliomyia hominivorax), eradicated from Central America, Mexico, and the U.S. over 30 years ago at an approximate cost of $800 million, is making a dangerous comeback. Illegal cattle trafficking has fueled the parasite’s rapid resurgence across Central America, with the recent confirmation of the first screwworm case in Mexico on November 23, 2024. In response, the U.S. Department of Agriculture (USDA) has temporarily halted live cattle imports from Mexico, underscoring the severe risks to livestock, public health, and rural economies.

The following statement was released by Jeremy Radachowsky, Wildlife Conservation Society’s Regional Director for Mesoamerica: 

“Evidence directly links illegal cattle trafficking to the screwworm’s resurgence. Major screwworm outbreak hotspots closely mirror cattle smuggling routes identified in InSight Crime's 2022 report, “Cash Cows – The Inner Workings of Cattle Trafficking from Central America to 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. 

“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. The screwworm itself can infect any warm-blooded animal, including livestock, wildlife, pets, and even humans. Furthermore, illegal cattle ranching in Central America drives deforestation, displaces Indigenous communities, and facilitates crimes such as drug trafficking and money laundering, all under the pretense of satisfying global beef demand. 

Over one million Mexican cattle producers are calling for immediate action to stop illegal cattle crossings across the Guatemala-Mexico border. Without decisive intervention, the screwworm's unchecked spread could cause catastrophic economic losses, devastate rural economies, and trigger a public health crisis.

“WCS urges the United States and Mexico to implement the following measures immediately:

1. Strengthen enforcement at key border crossings between Guatemala and Mexico, particularly at Benemérito de las Américas and El Ceibo.
2. Enforce stricter regulations and penalties to curb illegal livestock movement.
3. Enhance collaboration between governments and stakeholders to dismantle illegal cattle routes and halt the parasite's advance.