Parasitology: The Human Botfly

Horses are the victims of a botfly that lays its eggs on their legs, and sheep are the prey of another kind of botfly that lays its eggs in their noses. The eggs hatch into maggots which mature in the animals’ bodies causing severe illness and sometimes death. So far, the U.S. has been spared the activities of yet another botfly, still more repulsive, that makes man its unwilling and miserable host. But in this week’s A.M.A. Journal, a Florida doctor reports that the U.S. has just had a narrow escape from being colonized by the unpleasant critters.

Dr. Harry D. L. Kaye of Coral Gables was treating a 54-year-old engineer for a messy infection of the left ear that had not yielded to penicillin. Then the engineer remembered that on a hunting trip in Venezuela he had been bitten on the ear, and later had felt a wriggling sensation inside it. Surgeon Kaye set to work to clean out what seemed like a purulent cyst, and in it he found a white maggot, almost an inch long. Two days later, he removed another maggot. The Department of Agriculture’s Entomologist Richard P. Higgins identified the doctor’s find as larvae of the human botfly, known to scientists as Dermatobia hominis.

If the larvae had been allowed to mature they would have turned into half-inch flies resembling bluebottles, with yellow heads and blue-grey bodies. The human botfly does not bite or lay its eggs on people, but enslaves smaller flies and mosquitoes by gluing its eggs to their bodies. When the slave bites a victim, the eggs hatch into larvae which bore into him. And, says Dr. Kaye, two of them might have been enough to start a general infestation of the U.S. with another painful pest.