Findings about ticks brought transition in philosophy
Willy Burgdorfer, 89, who sparked a transition of wildlife management focus from propagating deer to be hunted to culling deer as a disease vector, died from complications of Parkinson’s Disease on November 17, 2014 in Hamilton, Montana.
Burgdorfer had no intention of promoting deer culling. A medical entomologist, Burgdorfer had earned his undergraduate degree in zoology, but was not particularly interested in deer, wildlife management, or hunting.
The cofounder of a youth soccer league, his favorite sport was European rules football. Ticks were his consuming interest.
Eulogized Program for Monitoring Emerging Disease (ProMED) viral diseases moderator Tom Yuill, “Willy Burgdorfer will long be recognized for his having discovered the Lyme disease spirochete named after him, Borellia bergdorferi.”
Born in Basel, Switzerland, Burgdorfer earned his zoology degree and a doctorate in parasitology and bacteriology from the University of Basel and the Swiss Tropical Institute, respectively.
Burgdorfer relocated to Hamilton, Montana, in 1951 on a U.S. Public Health Service fellowship to study the wood ticks that in 1906 had been identified as the transmission vector for Rocky Mountain spotted fever.
“In the early 1980s,” recalled New York Times obituarist William Yardley, “Burgdorfer was analyzing deer ticks from Long Island that were suspected to have caused spotted fever when he stumbled on something unexpected under his microscope: spirochetes, disease-causing bacteria shaped like corkscrews.”
Burgdorfer “had not been working on Lyme disease,” Yardley continued, “but he had spoken with the doctor who helped discover it, Allen Steere of Yale University. After Burgdorfer saw the spirochetes in the Long Island ticks, he quickly realized that the bacteria might also be in the deer ticks believed to be playing a role in Lyme disease in Connecticut and elsewhere, including Long Island. Deer ticks had not been known to carry spirochetes, but more testing proved him right. In 1982, he and several colleagues published the findings in the journal Science.”
Afflicting about 300,000 Americans per year, according to the Centers for Disease Control & Prevention, Lyme disease was named for Old Lyme, Connecticut, where it was first identified in 1975.
“Deer ticks” afflict rodents
Deer ticks are somewhat misnamed, in that they primarily infest rodents. Deer, however, are the carriers believed to most often translocate deer ticks from place to place.
Therefore, explained ProMed wildlife moderator Pablo M. Beldomenico in February 2014, “More deer represent more opportunities for female ticks to engorge and lay hundreds of eggs that will produce larvae that primarily feed on rodents, some of whom will be infected.”
Further, as Deerland author Al Cambronne points out, “The U.S. now has over 30 million deer, a hundred times more than a century ago,” largely as result of almost a century of enforcement of “buck laws,” which encourage hunters to shoot bucks but spare does, so that they will bear more fawns.
From “buck laws” to culling
The abundance of deer, coupled with the widespread belief that deer are to blame for Lyme disease, has contributed to the partial reform of “buck laws” in many states, to encourage doe hunting in order to stabilize the deer population; to increased promotion of bowhunting from tree stands in suburban areas, as a purportedly safer and more societally acceptable way to kill deer in back yards and parks than traditional deer-stalking with rifles; and to the emergence of deer culling as a fast-growing branch of the nuisance wildlife control industry.
Incorporated as a nonprofit organization, the deer culling firm White Buffalo Inc., of Moodus, Connecticut, reports annual revenues ranging from circa $400,000 to $785,000. White Buffalo is believed to be the leader in the field, but since for-profit deer culling companies are not required to publish financial data, it is not clear whether White Buffalo has major rivals.
But while deer ticks are the major vectors for Lyme disease in the eastern U.S., “Other ticks and biting insects such as mosquitoes, deer flies, and horse flies have been shown to carry the Lyme disease bacterium,” ProMed infectious diseases moderator Tam Garland posted in February 2014.
“The relationship between deer and the disease is complex. Deer show no symptoms of the disease. Deer may carry small numbers of the spirochete that causes Lyme disease, but they are dead-end hosts for the bacterium. Deer cannot infect other animals directly,” Garland continued, “and no deer hunter has acquired the disease from dressing out a deer. Infected ticks that drop from deer present little risk to humans or other animals, since the ticks are now at the end of their life cycle and will not feed again.
“These ticks are just as capable of being on dogs, or cats, or any human. These ticks are very adaptable to a variety of hosts. Culling deer does not prevent the tick from adapting to dogs, cats, people, horses, or any other hosts,” Garland finished. “With mosquitoes, deer flies, and horse flies more than capable of carrying the bacterium, culling deer may not solve the Lyme disease problem.”
(See also Deerland: America’s Hunt for Ecological Balance & the Essence of Wilderness, by Al Cambronne.)