disease Archives - Prairie Dog Pals

A Novel Retrovirus (Gunnison’s Prairie Dog Retrovirus) Associated With Thymic Lymphoma in Gunnison’s Prairie Dogs in Colorado, USA

June 8, 2020 by PDP

Abstract

As part of research and wildlife disease surveillance efforts, we performed necropsy examinations of 125 free-ranging (n = 114) and captive (n = 11) prairie dogs in Colorado from 2009 to 2017. From these cases, we identified three cases of thymic lymphoma in free-ranging Gunnison’s prairie dogs (Cynomys gunnisoni), and we identified a novel retroviral sequence associated with these tumors. The viral sequence is 7700 nucleotides in length and exhibits a genetic organization that is consistent with the characteristics of a type D betaretrovirus. The proposed name of this virus is Gunnison’s prairie dog retrovirus (GPDRV). We screened all 125 prairie dogs for the presence of GPDRV using PCR with envelope-specific primers and DNA extracted from spleen samples. Samples were from Gunnison’s prairie dogs (n = 59), black-tailed prairie dogs (Cynomys ludovicianus) (n = 40), and white-tailed prairie dogs (Cynomys leucurus) (n = 26). We identified GPDRV in a total of 7/125 (5.6%) samples including all three of the prairie dogs with thymic lymphoma, as well as spleen from an additional four Gunnison’s prairie dogs with no tumors recognized at necropsy. None of the GPDRV-negative Gunnison’s prairie dogs had thymic lymphomas. We also identified a related, apparently endogenous retroviral sequence in all prairie dog samples. These results suggest that GPDRV infection may lead to development of thymic lymphoma in Gunnison’s prairie dogs.

Molly D Butler¹, Karen Griffin², Connie D Brewster¹, Marylee L Kapuscinski¹, Mark D Stenglein¹, Daniel W Tripp², Sandra L Quackenbush¹, Karen A Fox²

Affiliations

PMID: 32498297
DOI: 10.3390/v12060606

Rabbit Hemorrhagic Disease Virus 2 Confirmed in Wild Rabbits in the United States

April 23, 2020 by PDP

Rabbit hemorrhagic disease virus 2 (RHDV2), a notifiable foreign animal disease, has been confirmed for

the first time in wild rabbits in the United States.

Medieval diseases are making a grim comeback

October 21, 2017 by PDP

The Black Death was little short of a bacterial apocalypse. The outbreak of bubonic plague, imported along the Silk Road, is thought to have killed between 25m and 50m people as it rampaged through 14th-century Europe. The disease thence resurfaced sporadically: the Great Plague of London, for example, felled a fifth of city dwellers in the 1660s.

While the plague seems to us a medieval affliction, it has never fully disappeared. On average, about 500 cases are documented globally each year, mostly in Africa, South America and India. The infection is treatable with antibiotics if caught early.

RESEARCHERS FINDING SUCCESS FIGHTING PLAGUE IN PRAIRIE DOG COLONIES

June 17, 2014 by PDP

GUNNISON, Colo. – Work to protect the Gunnison’s prairie dog by Colorado Parks and Wildlife has proven successful during the last four years and biologists are continuing with more research to improve methods to sustain populations.

“In some situations prairie dogs can be seen as pests, but they are critical in the environment and help to promote survival of numerous other species such as burrowing owls, badgers and raptors,” said Dan Tripp, a wildlife disease researcher with Colorado Parks and Wildlife.

In Colorado there are three species of prairie dogs. The Gunnison’s prairie dog resides primarily in the southwest portion of the state. The others are the white-tailed prairie dog which lives mainly in northwestern Colorado, and the black-tailed prairie dog which inhabits areas along the Front Range and eastern plains.

Plague, caused by a non-native bacteria carried by fleas, has been identified as a threat to the stability of Gunnison’s prairie dog populations in Colorado. Outbreaks of plague frequently kill every prairie dog in a colony. To combat the disease, agency biologists are dusting prairie dog burrows with an insecticide powder that kills fleas. Researchers are also evaluating the efficacy of oral vaccine baits which may prevent plague in the animals.

The bacteria that causes plague was transported to North America around 1900 and was subsequently found in Colorado around 1940. Because prairie dogs did not evolve with the bacteria, they carry little immunity to fight off the disease.

“The plague bacteria is a non-native invasive species that devastates prairie dogs and other wildlife species. We’re not attempting to upset nature’s balance with these treatments. We are working to restore balance in the environment and reduce the risk of major plague outbreaks in prairie dog colonies,” Tripp said. “We lose a lot of resilience in the environment when we lose prairie dogs.”

Controlling plague in prairie dogs may also help limit potential exposure to people and their pets.

In 2010, CPW biologists started dusting some burrows in the Gunnison Basin with an insecticide that kills fleas. The experiment has worked. In some cases, nearby colonies that were not dusted were wiped out by plague while colonies that were dusted remain healthy. Biologists also said that they’re seeing many more prairie dogs in more areas in the basin this year compared to five years ago.

Although the insecticide is not harmful to other species, applying it is labor intensive and expensive. For dusting to be effective every burrow in a colony must receive an application annually.

A potentially promising treatment is the oral sylvatic plague vaccine, Tripp said. Developed by the U.S. Geological Survey’s National Wildlife Health Center, the vaccine—still in the experimental stage—works well in the laboratory. It is administered in a cube flavored with peanut butter. The baits also contain a red dye that adheres to animals’ coats which helps researchers track the prairie dogs that eat the bait. This is only the second year that the vaccine has been tested in the field in Colorado. Longer term monitoring will be needed to determine its efficacy.

“So far, we’re encouraged by the results and we are optimistic that the vaccine will be effective in limiting future plague outbreaks,” Tripp said.

In the Gunnison area, four prairie dog colonies are being used for vaccine testing. Two colonies are receiving the vaccine bait, two are receiving no treatment. In Teller County the test is being conducted with two colonies.

The vaccine is also being tested in Arizona, Montana, South Dakota, Texas, Utah, and Wyoming. The experiment will continue for another two years and is a collaborative effort among more than 30 federal, state and tribal agencies and nongovernmental organizations.

In Colorado, the vaccine research in Gunnison’s prairie dogs is occurring on public land—state wildlife areas, BLM and National Park Service property.

Contrary to public perception, prairie dogs don’t reproduce prolifically. Females have only one litter of 3-5 pups each year and the natural mortality rate of the young is about 50 percent. Consequently, the colonies generally do not spread rapidly over wide areas. Tripp explained that few connections between colonies across a landscape exist; so when a colony is wiped out it may have little chance of being re-colonized.

“By preventing plague we can have healthy, stable prairie dog colonies that we can manage on public lands,” Tripp said.

The conservation work is aimed at preserving the ecological niche of prairie dogs and preventing a listing of the Gunnison’s prairie dog under the federal Endangered Species Act. If the animal is listed it could lead to various land-use restrictions.

J Wenum, area wildlife manager in Gunnison, explained that when landscapes are restored to a more natural condition, more uses can be accommodated.

“If you have healthy, functioning landscapes you don’t have to be focused on limiting uses,” Wenum said. “A healthy landscape will accommodate agriculture, recreation and wildlife.”

The testing of the oral vaccine will continue for a few more years, and biologists are cautiously optimistic that the vaccine will prove to be effective at limiting plague.

“We won’t be able to prevent plague in every colony. But this work will help to stabilize the overall population at its current distribution and benefit this important species,” Tripp said.

For more information about prairie dogs and other wildlife species, see cpw.state.co.us.

Gunnison’s Prairie Dogs

September 11, 2010 by PDP

Description: Yellowish buff mixed with black above, slightly paler below. Short, white-tipped tail. Terminal half of tail grayish white in center. 12-14″ in height, weighing 23-42 ounces. Lives 3-5 years in the wild, longer in captivity.

Similar Species: White-tailed and Utah prairie dogs have white in center of tail rather than grayish. Black-tailed Prairie Dog’s tail has black tip.

Breeding: 1 litter per year of 1–8 young, born in early May; gestation 27–33 days, pups emerge mid June.

Habitat: Short grass prairies in high mountain valleys and plateaus of southern Rocky Mountains at elevations of 6,000–12,000’ (1,800–3,600 m). Habitat is much more variable topographically and vegetationally than that of the Black-tailed Prairie Dog, which occurs at lower elevations.

Range: Southeastern Utah, south and central Colorado, northeast and central Arizona, and northwest New Mexico.

Discussion: The Gunnison’s Prairie Dog, like the rest of its kin, is active only when the sun is up, and is most energetic near dawn and dusk. It is constantly vigilant while aboveground, often sitting upright on its hind feet while it pursues its main activities: mainly feeding, but also grooming and playing. This animal generally is seen from April to October. It hibernates (torpor) in winter, living on stored body fat. It usually emerges in April, though they will emerge earlier if the winter is mild. Gunnison’s Prairie Dog feeds on green vegetation, particularly grasses, but also forbs, sedges, and shrubs, as well as a few insects. Its colonies are generally smaller and less closely knit than those of other prairie dogs, resembling ground squirrel aggregations, with fewer than 50 to 100 individuals. The animals in the colony cannot always see one another because their habitat is in such varied and patchy terrain, which is caused in part by human activities. On flat ground and where this prairie dog is protected colonies are much larger and more extensive. This species’ burrow systems can be up to 80 feet long and 16 feet deep in well-established colonies. Burrows can have food storage, flood, nesting, communal and excrement chambers. Territoriality is not well developed in Gunnison’s Prairie Dog, although old males may defend small areas outside their burrows. Mother-young relationships form the basic social unit. Newborns remain in the burrow about three weeks before emerging and are weaned about three weeks later. The female sits almost straight up on her haunches to nurse her young, who suckle either pectoral or inguinal (hind leg) nipples. Gunnison’s alarm call, distinctive among prairie dogs, is important to the survival and structure of the community. It is a series of high-pitched barks of one or two distinct syllables, with the second syllable lower and more guttural. The call may be repeated frequently and may continue for as long as half an hour. It increases in intensity as danger escalates, and ends in chatter as the animal enters its burrow. Predators include American Badgers, Coyotes, weasels, and raptors. Plague (Yersina pestis), carried by fleas, can decimate populations of this species. However, humans, through their extermination programs, are the chief enemy of Gunnison’s Prairie Dog.