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Why The US Drops Millions of Flesh Eating Worms On Central America Every Day
A battle against the worst animal you’ve never heard of
The New World Screwworm (NWS) is so terrifying that its Latin name, Cochliomyia hominivorax, literally means man eater. But despite its fearsome reputation, few people today know about or remember the scourge that these flies were in rural areas stretching from Florida to California and southward to the Panama Canal.
The NWS is known for laying thousands of tiny eggs, between 200 and 500 per clutch, in open wounds on mammals. When these eggs hatch, they disgorge hundreds of tiny worms, which then dig into the exposed flesh. The infection is incredibly painful. Any attempts to remove the worms often result in them digging (or screwing, hence the name) deeper into the flesh. As you can imagine, having hundreds of tiny worms feasting on your flesh is painful, and if left untreated, the results can be deadly.
Screwworms are so dangerous because one infestation can breed hundreds of flies, which go on to lay thousands of eggs in surrounding animals. Screwworms are not picky about their hosts. They will tear into the flesh of cattle, squirrels, deer, dogs, and even humans, infecting them. Cattle were long the favored host for these worms, and they feasted on the large populations of cows in the Southern United States and Mexico. Old time ranchers will still be able to tell you horror stories of calves writhing in pain before dying and having hundreds of dreaded New World Screwworm Flies pour out of the corpse.
The Latin name, again, meaning man eater, came from a particularly nasty infestation in South America. An island prison known as Devil’s Island was home to thousands of these awful flies, and they killed hundreds of people over a period of years. Not only do the flies lay eggs in wounds but the larvae also eat the flesh itself. The presence of the screwworms in a wound prevents the wound from healing, and the eating of the flesh by the worms causes them to enlarge and remain open, which invites infection and death.
For decades, between 1900 and 1950, millions of dollars in cattle were killed by screwworms. Infestations could devastate ranches and lead to massive losses in productivity. The worms were…
