Jack C Rhyan

Publications of Jack C Rhyan

• Failure of fallow deer (Dama dama) to develop chronic wasting disease when exposed to a contaminated environment and infected mule deer (Odocoileus hemionus).

  Authors: Jack C Rhyan, Michael W Miller, Terry R Spraker, Matt McCollum, Pauline Nol, Lisa L Wolfe, Tracy R Davis, Lynn Creekmore, Katherine I O'Rourke

  Journal of wildlife diseases. 07/2011; 47(3):739-44.

  We monitored a herd of fallow deer (Dama dama) for evidence of prion infection for 7 yr by periodic postmortem examination of animals from the herd. The fallow deer were exposed to the chronicWe monitored a herd of fallow deer (Dama dama) for evidence of prion infection for 7 yr by periodic postmortem examination of animals from the herd. The fallow deer were exposed to the chronic wasting disease (CWD) agent from mule deer by living in a paddock considered contaminated with infectivity from its history of housing CWD infected deer and, after the first year of the study, by comingling with infected mule deer (Odocoileus hemionus). At least 8 of 12 mule deer serving as sentinels for prion transmission and 25 additional mule deer serving as sources of infectivity developed clinical CWD or were otherwise confirmed to be infected with CWD via lymphoid tissue immunohistochemistry (IHC). In contrast, none of the 41 exposed fallow deer showed clinical signs suggestive of CWD, IHC staining of disease-associated prion in lymphoid or brain tissues, or evidence of spongiform degeneration in sections of brain stem at the level of the obex when sampled 18 mo to 7 yr after entering the mule deer paddock. The absence of clinical disease and negative IHC results in fallow deer housed in the same contaminated paddock for up to 7 yr and almost continuously exposed to CWD-infected mule deer for up to 6 yr suggests a species barrier or other form of resistance preventing fallow deer infection by the CWD agent or delaying progression of the disease in this species.

• Evaluation of two short-term anesthetic protocols in captive juvenile pronghorn (Antilocapra americana).

  Authors: Khursheed R Mama, Samantha Uhrig, David S Miller, Lauren Harris, Melissa Syndergaard, Marianne Regnier, Jack C Rhyan

  Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians. 12/2009; 40(4):803-5.

  Safe and efficacious anesthesia is required to facilitate biomedical procedures in pronghorn (Antilocapra americana). Two short-term anesthesia protocols were evaluated in 10 juvenile male pronghornSafe and efficacious anesthesia is required to facilitate biomedical procedures in pronghorn (Antilocapra americana). Two short-term anesthesia protocols were evaluated in 10 juvenile male pronghorn raised in captivity. Following i.m. medetomidine (0.1 mg/kg), pronghorn received either intravenous propofol (P) or ketamine (K). Behavioral and physiologic parameters were assessed for 15 min prior to atipamezole (0.2 mg/kg, i.m.) administration. Quantitative and qualitative values following both protocols were similar. Mean induction times were 80 +/- 23 and 75 +/- 15 sec after K and P, respectively. Arterial pressure decreased over time, and hypoxemia was evident (PaO2 51 +/- 4 mmHg) following both treatments.

• Pathogenesis and epidemiology of brucellosis in yellowstone bison: serologic and culture results from adult females and their progeny.

  Authors: Jack C Rhyan, Keith Aune, Thomas Roffe, Darla Ewalt, Steve Hennager, Tom Gidlewski, Steve Olsen, Ryan Clarke

  Journal of wildlife diseases. 08/2009; 45(3):729-39.

  Our objective in this prospective study was to determine the natural course of Brucella abortus infection in cohorts of seropositive and seronegative, female bison (Bison bison) and their offspringOur objective in this prospective study was to determine the natural course of Brucella abortus infection in cohorts of seropositive and seronegative, female bison (Bison bison) and their offspring in Yellowstone National Park (YNP) for 5 yr. We collected specimens from 53 adult females and 25 calves at least once and from 45 adults and 22 calves more than once. Annual seroconversion rates (negative to positive) were relatively high (23% for calves and juvenile bison, 6% in the total sample of adult female bison in our study, and 11% in the adult females that began the study as seronegatives). Antibody was not protective against infection, even for calves that passively received antibody from an infected mother's colostrum. Antibody levels stayed remarkably constant, with only a slow decline over time. We found only two seroconversions from a weak positive status to negative. Infected bison aborted and shed viable bacteria. Risk of shedding infective Brucella was highest for bison in the 2 yr following seroconversion from negative to positive. In one bison, we detected shedding for 3 yr following seroconversion. Regardless of serostatus of dams and neonates, most calves were seronegative by 5 mo of age. There was no relationship between the antibody status of the dam and the tendency of a calf to seroconvert to positive during the duration of the study.

• Use of infrared thermography to detect thermographic changes in mule deer (Odocoileus hemionus) experimentally infected with foot-and-mouth disease.

  Authors: Mike R. Dunbar, Shylo R. Johnson, Jack C Rhyan, Matt McCollum

  Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians. 07/2009; 40(2):296-301.

  Infrared thermography (IRT) measures the heat emitted from a surface, displays that information as a pictorial representation called a thermogram, and is capable of being a remote, noninvasiveInfrared thermography (IRT) measures the heat emitted from a surface, displays that information as a pictorial representation called a thermogram, and is capable of being a remote, noninvasive technology that provides information on the health of an animal. Foot-and-mouth disease (FMD) caused by FMD virus (FMDV) is a severe, highly communicable viral disease of cloven-hoofed animals, including both domestic and wild ruminants. Early detection of the disease may reduce economic loss and loss of susceptible wildlife. The objective of this study was to evaluate the use of IRT to detect possible heat changes associated with sites of infection with FMDV in experimentally infected mule deer (Odocoileus hemionus). Infection occurred through either inoculation with FMDV or exposure to inoculated animals. Early vesicular lesions were observed on the mouth, feet, or both within 24 hrs postinoculation and 48-96 hrs post-exposure. From internal temperature sensors, the exposed animals' body temperatures elevated significantly from the pre-infection temperature (38.8 degrees C, P < or = 0.002) starting the day before any lesions were observed. Body temperature was also found not to be significantly different from eye temperatures of well-focused thermograms. For feet thermograms, the mean of the daily maximum (MMAX) foot temperature rose significantly (P = 0.017) from two days before (27.3 degrees C +/- 1.9 degrees C SE) to the maximum MMAX observed (33.0 degrees C +/- 2.0 degrees C SE) at two days after the first foot lesion occurrence. These observed changes indicate that IRT may be a rapid, remote, and noninvasive method to screen for suspect animals in order to test further for FMDV infection during an FMD outbreak.

• Variation in Pasteurella (Bibersteinia) and Mannheimia spp. following transport and antibiotic treatment in free-ranging and captive Rocky Mountain bighorn sheep (Ovis canadensis canadensis).

  Authors: Glen C Weiser, David S Miller, Mark L Drew, Jack C Rhyan, Alton C S Ward

  Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians. 04/2009; 40(1):117-25.

  Morbidity and mortality associated with respiratory disease following capture and translocation of bighorn sheep (Ovis canadensis canadensis) is a significant concern, particularly when establishingMorbidity and mortality associated with respiratory disease following capture and translocation of bighorn sheep (Ovis canadensis canadensis) is a significant concern, particularly when establishing new or augmenting existing bighorn populations. Administration of prophylactic antibiotics at the time of capture is often done to minimize the risk of respiratory disease, but the efficacy of this practice is unknown. The effects of oxytetracycline and florfenicol on the Pasteurella (Bibersteinia) and Mannheimia spp. isolated from samples collected from the oropharynx at the time of capture and 3 or 42 day later were evaluated in two groups of bighorn sheep. The most evident change in the isolation rates or types of Pasteurella (Bibersteinia) spp., Mannheimia spp., or both was an increase of beta-hemolytic strains isolated from bighorn sheep 3 day following oxytetracycline treatment. Both groups of bighorn sheep carried Pasteurella (Bibersteinia) trehalosi identified as the same biovariants, but they did not share biovariants of Mannheimia spp. No animals had signs of respiratory disease. Isolates representative of all biovariants present in cultures from the two bighorn sheep groups were sensitive to in vitro tests to both oxytetracycline and florfenicol and the majority were also sensitive to seven other antibiotics tested. The administration of neither oxytetracycline nor florfenicol eliminated Pasteurella (Bibersteinia) or Mannheimia from the oropharyngeal mucosa. Resistance to either antibiotic used in these animals was not noted. Although the prophylactic benefits of these drugs in preventing disease are uncertain, therapeutic levels of antibiotics in lung tissue during times of stress may reduce the risk of disease. Representative sampling of the oropharyngeal microflora of bighorn sheep source and recipient populations prior to being intermingled should be considered as one of the tools to minimize exposure of naive populations to potentially pathogenic bacteria.

• Experimental Infection of Richardson's Ground Squirrels (Spermophilus richardsonii) with Attenuated and Virulent Strains of Brucella abortus.

  Authors: Pauline Nol, Steven C Olsen, Jack C Rhyan

  Journal of wildlife diseases. 02/2009; 45(1):189-195.

  A previous investigation of the safety of Brucella abortus strain RB51 (sRB51) in various nontarget species suggested that Richardson's ground squirrels (Spermophilus richardsonii) may developA previous investigation of the safety of Brucella abortus strain RB51 (sRB51) in various nontarget species suggested that Richardson's ground squirrels (Spermophilus richardsonii) may develop persistent infections when orally inoculated with the vaccine. In the present study, sRB51, B. abortus strain 19 (s19), and virulent B. abortus strain 9941 (s9941) were administered orally to Richardson's ground squirrels to further characterize B. abortus infection in this species. Six groups of nongravid ground squirrels were orally inoculated with 6 x 10(8) colony forming units (cfu) sRB51 (n = 10), 2.5 x 10(4) cfu s19 (n = 10), 2.5 x 10(7) cfu s19 (n = 6), 1.3 x 10(6) cfu s9941 (n = 5), 2.1 x 10(8) cfu s9941 (n = 5), or vaccine diluent (control; n = 4). One of five animals in the lower-dose s19 group and two of three animals in the higher-dose s19 group showed persistence of bacteria in various tissues at 14 wk postinoculation (PI). At 18 wk PI, one of five animals in the sRB51 group and one of five animals in the high-dose s9941 group were culture positive. Although we did detect some persistence of B. abortus strains at 18 wk, we found no evidence of pathology caused by B. abortus strains in nonpregnant Richardson's ground squirrels based on clinical signs, gross lesions, and microscopic lesions.

• The Single-Shot GnRH Immunocontraceptive Vaccine (GonaCon) in White-Tailed Deer: Comparison of Several GnRH Preparations.

  Authors: Lowell A. Miller, James P. Gionfriddo, Kathleen A. Fagerstone, Jack C Rhyan, Gary J. Killian

  American journal of reproductive immunology (New York, N.Y. : 1989). 10/2008; 60(3):214-23.

  Problem An effective, single-injection, multi-year, GnRH contraceptive agent is needed to control reproduction in overabundant white-tailed deer populations. Method of study Two GnRH conjugates,Problem An effective, single-injection, multi-year, GnRH contraceptive agent is needed to control reproduction in overabundant white-tailed deer populations. Method of study Two GnRH conjugates, GonaCon(trade mark) (GnRH-KLH) and GonaCon-B(trade mark) (GnRH-blue protein), were prepared in emulsion form as one-injection and two-injection immunocontraceptive vaccine formulations. In addition, the GnRH-KLH protein conjugate was lyophilized and suspended in AdjuVac(trade mark) adjuvant to produce a fifth vaccine formulation. Each formulation was administered to a group of five captive adult female white-tailed deer. Reproductive performance of treated female deer was monitored for 5 years to determine the comparative efficacy of the various treatments. Results The longevity of the contraceptive response (2-5 years) was strongly influenced by the design of the conjugate antigen, the adjuvant used, and the delivery form of the vaccine. Conclusion One-injection and two-injection formulations of GonaCon(trade mark) and GonaCon-B(trade mark) produced multi-year contraception in adult female white-tailed deer. GonaCon-B(trade mark) provided a longer lasting contraceptive effect.

• Comparison of immune and adverse effects induced by AdjuVac and Freund's complete adjuvant in New Zealand white rabbits (Oryctolagus cuniculus).

  Authors: Jenny G Powers, Paul B. Nash, Jack C Rhyan, Christi A Yoder, Lowell A. Miller

  Lab animal. 11/2007; 36(9):51-8.

  Though Freund's complete adjuvant effectively increases immune response to vaccines in various species, its potentially severe inflammatory effects have led many animal researchers to seekThough Freund's complete adjuvant effectively increases immune response to vaccines in various species, its potentially severe inflammatory effects have led many animal researchers to seek alternative immunological adjuvants. In a study of New Zealand white rabbits, the authors compared the immune and adverse effects of Freund's complete adjuvant with the effects of two formulations of AdjuVac, an immunological adjuvant previously developed by their group. All three adjuvants improved humoral immune response but also caused inflammation. Inflammatory reactions caused by AdjuVac, however, tended to be less severe than those caused by Freund's complete adjuvant.

• Contraception of bison by GnRH vaccine: a possible means of decreasing transmission of brucellosis in bison.

  Authors: Lowell A. Miller, Jack C Rhyan, Mark Drew

  Journal of wildlife diseases. 11/2004; 40(4):725-30.

  Preventing pregnancy in brucellosis-infected bison (Bison bison) provides a potential means of preventing transmission of disease. To determine whether a gonadotropin-releasing hormone (GnRH) vaccinePreventing pregnancy in brucellosis-infected bison (Bison bison) provides a potential means of preventing transmission of disease. To determine whether a gonadotropin-releasing hormone (GnRH) vaccine was effective in reducing pregnancy in bison and to study the safety of injecting GnRH in pregnant bison, a study was conducted at the Idaho Fish and Game Wildlife Health Laboratory in Caldwell, Idaho (USA). Four pregnant and two nonpregnant female bison were given a single injection of GnRH vaccine, and five pregnant adult females were given a sham injection that contained only adjuvant. Three of the GnRH-vaccinated bison that were pregnant at the time of vaccination delivered healthy calves. One treated bison had dystocia that resulted in a dead calf. All control bison delivered healthy calves. After calving, females of both groups were exposed to two bulls. Treated bison were palpated 6 wk after exposure to the bulls, and blood was drawn for pregnancy-specific protein B analysis. The six treated bison were not pregnant. The sham-treated bison became pregnant and delivered viable calves. This study demonstrates that a single dose of GnRH vaccine is effective in preventing pregnancy in female bison for at least 1 yr.

• Vaccine compositions and adjuvant.

  Authors: Lowell A. Miller, Jack C Rhyan

  The immune response of an animal to a target immunogen may be enhanced by use of a novel adjuvant which includes low concentrations of killed cells of Mycobacterium avium subspecies avium inThe immune response of an animal to a target immunogen may be enhanced by use of a novel adjuvant which includes low concentrations of killed cells of Mycobacterium avium subspecies avium in combination with mineral oil. The adjuvant may be used in vaccine compositions for the immunization of an animal against any target immunogen, and is particularly preferred for use with immunocontraceptive vaccines such as GnRH and PZP immunocontraceptive vaccines.