From Dateline (April 8, 2004)
Biologist Studies Plague and Prairie
by Dave Reid
What does Paul Stapp, a 21st-century biologist
specializing in small mammals, have in common with Daniel Defoe,
an 18th-century author and journalist?
Both are concerned with bubonic plague.
Defoe gave a famous account of the Black Death that
felled thousands of people in England during the summer and fall
of 1665 in A Journal of the Plague Year.
Stapp, with colleagues from Colorado State University,
is conducting research on the plague – which has killed thousands
of black-tailed prairie dogs in northern Colorado – thanks
to a $472,633 National Science Foundation grant.
“Prairie dogs are particularly susceptible
to the bubonic plague, which is spread mainly by fleas,” said
Stapp, assistant professor of biological science. “Fleas can
wipe out entire prairie dog colonies, which in some of the largest
colonies, may contain thousands of animals over hundreds of acres.”
Prairie dogs are highly social animals and also can
spread the disease orally, through “kissing” one another.
Main goals of the five-year grant are to find out
what becomes of plague-causing bacteria when a prairie dog colony
is decimated, and how plague moves from an infected to an uninfected
colony. Does the bacteria remain in the soil or migrate via fleas
to other animals that may be resistant to the disease? Is it spread
by infected prairie dogs leaving colonies or do other animals carry
the disease from one place to another?
Stapp also is investigating the relationship of climate
and plague outbreaks.
“There appears to be a correlation between the appearance
of El Niño climatic events and the incidence of plague,”
he said. “El Niño brings milder and wetter weather
to the Great Plains, which can influence the survival and numbers
of rodents and fleas.”
El Niño made an appearance two years ago and
may occur during the grant period, which would allow Stapp’s
team to study the entire plague cycle.
Because of their grass diet and burrow digging, prairie
dogs have been the bane of farmers and ranchers. In the 1800s and
1900s, there were intense efforts to get rid of prairie dogs, using
poisoning, shooting and other means, noted Stapp.
Previously unknown in North America, plague appeared
in Colorado around 1948. Human eradication efforts, combined with
plague and habitat loss due to agriculture and development, resulted
in declines in prairie dog populations. Recent protection given
to the creatures is expected to increase their numbers, which will
benefit a number of threatened species, such as the black-footed
ferret that depend on prairie dogs for food or habitat.
Several prairie dog towns are located north of Denver,
the general area of Stapp’s research. The animals, which can
weigh up to three pounds, have a normal life span of about five
Stapp, who earned his doctorate at Colorado State
University, was a postdoctoral researcher with UC Davis and a
postdoctoral fellow at the University of Wyoming.