Sheeva Aboutaleb
Mondays 7:00pm
Summary
Immunization of Black-tailed Prairie Dog Against Plague through
Consumption of Vaccine-laden Baits
Plague has been prevalent throughout the centuries in our world. Although cases are
not as common these days they still occur. In fact there is a plague caused by Yersinia pestis
that can affect the human population. This particular strain of plague is a disease in the wild
rodent populations around the world. It is passed through contact with such infested rodents.
Our prairie dog populations in western states such as New Mexico, Arizona, and Colorado have
contracted an outbreak which has followed the human geographical trend. Since they are
ground-dwelling creatures they are more susceptible to the plague and have a high mortality
rate once affected. Prairie Dogs are considered to be an important part of the ecosystem in
which they live, so stopping this outbreak is pertinent. A ferret species that greatly relied on
prairie dog burrows for shelter and food was almost extinct because of the plague. Not only did
it affect their “sister” species, but killed of many of the ferrets because they were highly
susceptible. To stop the rapid spread of the plague a oral immunization program was put in
place would get a raccoon poxivirus vaccine to the affected populations in the form of oral bait.
The materials and methods that were used to conduct this experiment include the
black-tailed praire dogs captured from wild troops in South Dakota. They were taken to the US
Geological Survey National Wildlife Health Center. There they were inspected for parasites,
chipped for identification and treated for fleas. After medical evaluation was complete the
animals were “group-housed into isolation rooms.” They were watered and fed fresh
vegetables once daily. The subjects were assigned to four different isolation rooms based on
the level of treatment. There was a negative control group who got the placebo baits. Then the
other three were given the vaccine-laden baits in different time intervals. One received one
time interval, the next two, and the last at three time intervals. After the controls were in place
two unvaccinated animals were placed in the room to serve as the uninfected contact control.
Vaccine-laden baits were consumed because food was with held for 48 hours. After identifying
each animal they were taken into a carrier where the bait was administered via small food
dishes that had a single vaccine-laden bait or the placebo. When three weeks of vaccine
administration had expired the plague was introduced to the population. Each prairie dog
received a subcutaneous injection of a diluted amount of the bacteria. When signs of the
disease became prevalent those infected were humanely euthanized. Then after twenty-eight
days all survivors were disposed of in the same fashion. Their bodies were frozen for future
evaluation.
After evaluating the data it was found that all of the prairie dogs consumed at least one
of the two baits that were offered in each time interval. When the plague was introduced every
treatment group became sick and died. The disease was identified in a culture of the liver of all
animals. In the control group that received placebo baits two animals were found to have
isolated the Y. pestis from a lesion at the injection site during necropsy, but the rest of the
tissues were affected. Survival turned out to be higher in groups two and three in comparison
to the placebo group. It was also found that gender did not play a role in survival. Overall, those
that consumed the vaccine-laden bait survived longer and had a higher antibody rate over the
twenty-eight day challenge.
Sheeva Aboutaleb
Works Cited
1. Immunization of Black-tailed prairie Dog against Plague through Consumption of
Vaccine-laden Baits, Tonie E. Rocke, Susan R. Smith, Dan T. Stinchcomb, Jorge E. Osorio
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