Medicine: Fleas on a Leg

A droll doctor is Rollo Eugene Dyer, assistant director of the National Institute of Health. His favorite drollery last summer was to pull up his trouser leg and exhibit a small, fine-meshed cage strapped to his skin. Friends peeping into the cage beheld a herd of fleas contentedly nipping at the doctor’s epidermis. Raillery was always in order. Dr. Dyer is a collector of stamps. Had he now become a flea collector? He is fond of dogs. Was he shielding his dogs from vermin? No, Dr. Dyer would chuckle, and his friends seldom realized that he had ceased his joshing when he said, “They’re fleas from a wild rat and I’m trying to see if they’ll kill me.” He was experimenting with flea transmission of typhus fever.

Last week Dr. Dyer, weak, emaciated and quavering, left Washington’s Naval Hospital. One of his caged fleas carried a virulent form of typhus fever which had almost killed him, had kept him bed-ridden for a month. But he was contented. He had demonstrated something more about typhus fever. In Europe the body louse carries the virus of typhus fever, transmits a form of the disease which kills 22% to 65% of its victims. In the U. S. there has been a so-called mild form of typhus with a 2% mortality.* Dr. Dyer was instructed by Director George Walter McCoy of the National Institute of Health to follow the lead of Dr. Kenneth Fuller Maxcy, who had left the Institute to become professor of public health and hygiene at the University of Virginia. Dr. Maxcy knew that U. S. inhabitants are seldom lousy, suspected that some other blood-sucking insect might be the vector of mild U. S. typhus. Dr. Dyer, who in his career had dealt with rat-borne bubonic plague, suspected rat fleas, proved his hypothesis correct—first on guinea pigs, next (by accident) on two assistants, Martin Joseph Mannix and Dr. Elmer Theodore Ceder, lastly upon himself. “Where,” he demanded as he wobbled home from the Naval Hospital, “Where do they get that ‘mild’ stuff?”

*Because the louse is most active in winter when people bundle up and huddle together, European typhus is called winter typhus. The U. S. type is summer typhus, because fleas then are most active. (Fleas hibernate in winter.)