An outbreak of deadly screw worm flies that carry a parasite (Cochliomyia hominivorax) infecting warm blooded animals in Central America has been linked to illegal cattle ranching. Unregulated movement of livestock through protected areas is accelerating the spread. New world screw worms larvae feed on the live flesh of wounded animals until the host dies,
A joint campaign to eradicate the pest in Mexico and Central America in the 80's and 90's was successful, but experts think it has reappeared in Panama after traveling through the thick jungles of the Darien Gap from South America. The Gap, which acts as an ecological barrier kept the parasite at bay for thirty years, but in recent years it has been repeatedly traversed by migrants and cattle.
Costa Rica experienced the outbreak this year. The flies quickly moved on to Nicaragua, then Guatemala and Honduras. Researchers at the National Autonomous University of Mexico are tracking the spread. If the parasite crosses into Mexico, which has a large cattle ranching industry, it could be impossible to stop. According to the World Conservation Society (WCS) there is a strong correlation between cattle smuggling routes and the fly. Deforestation and illegal cattle ranching overlaps with known outbreaks. [map]Drug traffickers rely on illegal cattle ranching to launder money. They mix untreated animals that have grazed in cleared areas with herds of healthy animals. The hardest hit protected area in Central America is Nicaragua's Bosawals Biosphere Reserve where non-indigenous squatters, known as colonos set up herds on cleared forest. The animals arrive at slaughterhouses through intermediaries with false ear tags making it impossible to trace the source. Honduras' Patuca National Park and Rio Platano Biosphere have been devastated by deforestation, loosing 13% of its primary forest cover between 2002 and 2020.
Flies also infect domestic animals and pets. It is not possible to know how many wild animals like tapirs, monkeys, sloths, and porcupines suffer from infection. That number will be great according to vets who have treated wild animals brought into rescue centers. If the plague reaches Mexico, which has an estimated population of 50,000 untreated cattle, authorities will be forced to act by suppressing the spread with sterile male flies. Conservationists want the plague stopped at its source by increasing the restrictions on illegal ranching and deforestation.