Publications by authors named "Terry Kreeger"

Prions are infectious proteins causing fatal, transmissible neurodegenerative diseases of animals and humans. Replication involves template-directed refolding of host encoded prion protein, PrPC, by its infectious conformation, PrPSc. Following its discovery in captive Colorado deer in 1967, uncontrollable contagious transmission of chronic wasting disease (CWD) led to an expanded geographic range in increasing numbers of free-ranging and captive North American (NA) cervids.

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We conducted a 10-yr study to establish whether chronic wasting disease (CWD) was readily transmissible to domestic cattle ( Bos taurus) following oral inoculation or by cohousing cattle with captive cervids in outdoor research facilities where CWD was enzootic. Calves ( n=12) were challenged orally on one occasion using brain homogenate derived from CWD-infected mule deer ( Odocoileus hemionus). Five uninoculated cattle served as unchallenged controls.

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Chronic wasting disease (CWD) is a fatal transmissible spongiform encephalopathy affecting white-tailed deer (Odocoileus virginianus), mule deer (Odocoileus hemionus), Rocky Mountain elk (Cervus elaphus nelsoni), and moose (Alces alces shirasi) in North America. In southeastern Wyoming average annual CWD prevalence in mule deer exceeds 20% and appears to contribute to regional population declines. We determined the effect of CWD on mule deer demography using age-specific, female-only, CWD transition matrix models to estimate the population growth rate (λ).

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Chronic wasting disease (CWD) is an invariably fatal transmissible spongiform encephalopathy of white-tailed deer, mule deer, elk, and moose. Despite a 100% fatality rate, areas of high prevalence, and increasingly expanding geographic endemic areas, little is known about the population-level effects of CWD in deer. To investigate these effects, we tested the null hypothesis that high prevalence CWD did not negatively impact white-tailed deer population sustainability.

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Seven grizzly (Ursus arctos; four male, three female) and three black (Ursus americanus; two male, one female) bears caught in culvert traps or leg snares were immobilized in northwestern Wyoming with carfentanil and xylazine at doses, respectively, of 0.011 ± 0.001 and 0.

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Free-ranging Alaskan moose calves (Alces alces gigas) were immobilized with 0.12 mg/kg sufentanil (S; n=16), 0.12 mg/kg sufentanil plus 0.

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From October 2009 through July 2010, five captive, 3-yr-old, female Rocky Mountain elk (Cervus elaphus) and nine free-ranging elk (one male, eight female) were immobilized with 0.1 mg/kg sufentanil plus 0.5 mg/kg xylazine which was antagonized with 1 mg/kg naltrexone and 2 mg/kg tolazoline.

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Overabundant populations of elk (Cervus elaphus) are a significant concern in some areas of the western United States because of potential ecologic damage and spread of brucellosis to domestic livestock. Brucella abortus is transmitted among elk through direct contact with aborted fetuses, placentas and associated fluids, or postpartum discharge of infected animals. Because transmission of brucellosis is dependent on pregnancy, contraception of cows could be used for both disease and population management.

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During February-April 2004, an estimated 400-500 free-ranging elk (Cervus elaphus) developed paresis, became recumbent, and died or were euthanized in the Red Rim Wildlife Habitat Management Area (RRWHMA), Wyoming, USA. Elk were found in sternal recumbency, alert and responsive, but unable to rise. Their condition progressed to lateral recumbency followed by dehydration, obtundation, and death.

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Three captive Shira's moose (Alces alces shirasi) were orally inoculated with a single dose (5 g) of whole-brain homogenate prepared from chronic wasting disease (CWD)-affected mule deer (Odocoileus hemionus). All moose died of causes thought to be other than CWD. Histologic examination of one female moose dying 465 days postinoculation revealed spongiform change in the neuropil, typical of transmissible spongiform encephalopathy.

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To investigate the possible presence of disease-associated prion protein (PrP(d)) in striated muscle of chronic wasting disease (CWD)-affected cervids, samples of diaphragm, tongue, heart and three appendicular skeletal muscles from mule deer (Odocoileus hemionus), white-tailed deer (Odocoileus virginianus), elk (Cervus elaphus nelsoni) and moose (Alces alces shirasi) were examined by ELISA, Western immunoblot and immunohistochemistry (IHC). PrP(d) was detected in samples of heart muscle from seven of 16 CWD-infected white-tailed deer, including one free-ranging deer, and in 12 of 17 CWD-infected elk, but not in any of 13 mule deer samples, nor in the single CWD-infected moose. For white-tailed deer, PrP(d) was detected by Western blot at multiple sites throughout the heart; IHC results on ventricular sections of both elk and white-tailed deer showed positive staining in cardiac myocytes, but not in conduction tissues or nerve ganglia.

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Nine (four female, five male) captive adult Rocky Mountain bighorn sheep (Ovis canadensis) contracted brucellosis caused by Brucella abortus biovar 4 as a result of natural exposure to an aborted elk (Cervus elaphus) fetus. Clinical signs of infection were orchitis and epididymitis in males and lymphadenitis and placentitis with abortion in females. Gross pathologic findings included enlargement of the testes or epididymides, or both, and yellow caseous abscesses and pyogranulomas of the same.

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Twelve adult female red deer (Cervus elaphus) were given 250 mg of ceftiofur sodium by intramuscular injection (i.m.) and ballistic implant in a crossover design.

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Brucellosis caused by infection with Brucella abortus is present in some elk (Cervus elaphus nelsoni) of the Greater Yellowstone Area (parts of Wyoming, Montana, and Idaho, USA). Since 1985, the Wyoming Game and Fish Department has vaccinated elk on elk feedgrounds in northwestern Wyoming during the winter months using B. abortus strain 19 (strain 19).

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In a study conducted from January to August 2000, elk (Cervus elaphus) were vaccinated with Brucella abortus strain RB51 (SRB51, n = 6) or injected with 0.15 M NaCl solution (n = 3) at approximately 6 mo of age. Beginning at 2 wk and continuing to 25 wk after vaccination, SRB51-vaccinated elk had greater antibody responses (P < 0.

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From January through July of 2000, a study was conducted to evaluate clearance, immunologic responses, and potential shedding of Brucella abortus strain RB51 (SRB51) following ballistic or subcutaneous (SQ) vaccination of 7 mo old bison (Bison bison) calves. Ten bison calves were vaccinated SQ with 1.4 x 10(10) colony-forming units (CFU) of SRB51 and five calves were inoculated SQ with sterile 0.

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Brucellosis is endemic in free-ranging elk (Cervus elaphus) and bison (Bison bison) in the Greater Yellowstone Area (GYA; USA). It is possible that an oral brucellosis vaccine could be developed and disseminated in the GYA to reduce disease transmission. Should this occur, non-target species other than elk and bison may come in contact with the vaccine resulting in morbidity or mortality.

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Brucella abortus strain RB51 is used as a vaccine because it induces antibodies that do not react on standard serologic tests for brucellosis allowing differentiation between vaccination and infection. Strain RB51 was evaluated in captive elk (Cervus elaphus) to determine if vaccination protected against abortion following experimental challenge. Thirty elk were vaccinated intramuscularly with 1.

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Bovine brucellosis is a serious zoonotic disease affecting some populations of Rocky Mountain elk (Cervus elaphus nelsoni) and bison (Bison bison) in the Greater Yellowstone Area, USA. The fear that elk and/or bison may spread Brucella abortus to livestock has prompted efforts to reduce or eliminate the disease in wildlife. Brucella abortus strain RB51 (RB51) vaccine has recently been approved for use in cattle.

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