Michael W Miller

Publications of Michael W Miller

• Assessment of prospective preventive therapies for chronic wasting disease in mule deer.

  Authors: Lisa L Wolfe, David A Kocisko, Byron Caughey, Michael W Miller

  Journal of wildlife diseases. 04/2012; 48(2):530-3.

  We compared prion infection rates among mule deer (Odocoileus hemionus) receiving pentosan polysulfate, tannic acid, tetracycline HCl, or no treatment 14 days before to 14 days after (dpi) oralWe compared prion infection rates among mule deer (Odocoileus hemionus) receiving pentosan polysulfate, tannic acid, tetracycline HCl, or no treatment 14 days before to 14 days after (dpi) oral inoculation with tonsil tissue homogenate. All deer were infected, but the rapid disease course (230-603 dpi) suggested our challenge was overwhelming.

• Survival Patterns in White-tailed and Mule Deer after Oral Inoculation with a Standardized, Conspecific Prion Dose.

  Authors: Michael W Miller, Lisa L Wolfe, Tracey M Sirochman, Michael A Sirochman, Jean E Jewell, Elizabeth S Williams

  Journal of wildlife diseases. 04/2012; 48(2):526-9.

  We orally inoculated white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) with a standardized, conspecific prion dose and collected biologic samples throughout the diseaseWe orally inoculated white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) with a standardized, conspecific prion dose and collected biologic samples throughout the disease course. Mule deer (PRNP genotype 225SS) and PRNP genotype 96GG white-tailed deer succumbed along similar trajectories, but 96GS- and 96SS-genotype individuals tended to survive longer.

• Salivary prions in sheep and deer.

  Authors: Gültekin Tamgüney, Jürgen A Richt, Amir N Hamir, Justin J Greenlee, Michael W Miller, Lisa L Wolfe, Tracey M Sirochman, Alan J Young, David V Glidden, Natrina L Johnson, Kurt Giles, Stephen J Dearmond, Stanley B Prusiner

  Prion. 01/2012; 6(1):52-61.

  Scrapie of sheep and chronic wasting disease (CWD) of cervids are transmissible prion diseases. Milk and placenta have been identified as sources of scrapie prions but do not explain horizontalScrapie of sheep and chronic wasting disease (CWD) of cervids are transmissible prion diseases. Milk and placenta have been identified as sources of scrapie prions but do not explain horizontal transmission. In contrast, CWD prions have been reported in saliva, urine and feces, which are thought to be responsible for horizontal transmission. While the titers of CWD prions have been measured in feces, levels in saliva or urine are unknown. Because sheep produce ~17 L/day of saliva, and scrapie prions are present in tongue and salivary glands of infected sheep, we asked if scrapie prions are shed in saliva. We inoculated transgenic (Tg) mice expressing ovine prion protein, Tg(OvPrP) mice, with saliva from seven Cheviot sheep with scrapie. Six of seven samples transmitted prions to Tg(OvPrP) mice with titers of -0.5 to 1.7 log ID 50 U/ml. Similarly, inoculation of saliva samples from two mule deer with CWD transmitted prions to Tg(ElkPrP) mice with titers of -1.1 to -0.4 log ID 50 U/ml. Assuming similar shedding kinetics for salivary prions as those for fecal prions of deer, we estimated the secreted salivary prion dose over a 10-mo period to be as high as 8.4 log ID 50 units for sheep and 7.0 log ID 50 units for deer. These estimates are similar to 7.9 log ID 50 units of fecal CWD prions for deer. Because saliva is mostly swallowed, salivary prions may reinfect tissues of the gastrointestinal tract and contribute to fecal prion shedding. Salivary prions shed into the environment provide an additional mechanism for horizontal prion transmission.

• Baylisascaris procyonis in raccoons (Procyon lotor) from eastern Colorado, an area of undefined prevalence.

  Authors: Deanna J Chavez, Ivy K Levan, Michael W Miller, Lora R Ballweber

  Veterinary parasitology. 11/2011;

  Baylisascaris procyonis is a zoonotic parasite that has been documented in raccoons throughout much of the United States; however, no published information on its occurrence is available for theBaylisascaris procyonis is a zoonotic parasite that has been documented in raccoons throughout much of the United States; however, no published information on its occurrence is available for the transition zone from the Great Plains to the Rocky Mountains. Because this parasite can cause neural larva migrans and diffuse unilateral subacute neuroretinitis in humans (as well as other hosts), a more complete understanding of the distribution of this parasite seems warranted for public health reasons. The purpose of this study was to begin to fill in the gaps in our knowledge of the distribution of B. procyonis in an area of the US where there is, currently, no published information available. Fifty-three raccoons were collected throughout eastern Colorado during 2007-2010. Forty-six were examined by necropsy and seven by fecal flotation. Age (11 juveniles, 25 adults) and sex (16 males, 19 females) of the raccoons were recorded when intact carcasses were available. When available, feces were further processed for the detection of Giardia and Cryptosporidium using a direct fluorescent antibody detection method. B. procyonis was found in 31 of 53 raccoons (58.5%, 95% CI=44.1%, 71.9%). Mean intensity was 11.7 with a range of 1-49 worms per infected individual. There was no significant difference between age or sex, and the presence of ascarids or the number of ascarids. Cryptosporidium spp. oocysts and Giardia spp. cysts were detected in 11/44 (25%; 95% CI: 13.2, 40.3) and 3/44 (6.9%; 95% CI: 1.4, 18.7) raccoons, respectively. The genotype of the Giardia present could not be determined. The genotype of five of six cryptosporidial isolates was 100% homologous to the skunk genotype while the sixth was 100% homologous to Cryptosporidium parvum. Based on these results, both B. procyonis and Cryptosporidium spp. appear to be prevalent in raccoons of eastern Colorado.

• Pasteurellaceae from Colorado bighorn sheep herds.

  Authors: Michael W Miller, Lisa L Wolfe

  Journal of wildlife diseases. 07/2011; 47(3):800-4.

  We compared phenotypic and genotypic characterizations of 88 Pasteurellaceae isolates from bighorn sheep (Ovis canadensis) in the course of exploring epizootiologic relationships. Based on ourWe compared phenotypic and genotypic characterizations of 88 Pasteurellaceae isolates from bighorn sheep (Ovis canadensis) in the course of exploring epizootiologic relationships. Based on our observations, adopting contemporary taxonomic conventions and using molecular methods to detect and compare Pasteurellaceae may help improve understanding of bighorn respiratory disease epizootiology and management.

• 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.

• Prion disease detection, PMCA kinetics, and IgG in urine from sheep naturally/experimentally infected with scrapie and deer with preclinical/clinical chronic wasting disease.

  Authors: Richard Rubenstein, Binggong Chang, Perry Gray, Martin Piltch, Marie S Bulgin, Sharon Sorensen-Melson, Michael W Miller

  Journal of virology. 06/2011; 85(17):9031-8.

  Prion diseases, also known as transmissible spongiform encephalopathies, are fatal neurodegenerative disorders. Low levels of infectious agent and limited, infrequent success of diseasePrion diseases, also known as transmissible spongiform encephalopathies, are fatal neurodegenerative disorders. Low levels of infectious agent and limited, infrequent success of disease transmissibility and PrP(Sc) detection have been reported with urine from experimentally infected clinical cervids and rodents. We report the detection of prion disease-associated seeding activity (PASA) in urine from naturally and orally infected sheep with clinical scrapie agent and orally infected preclinical and infected white-tailed deer with clinical chronic wasting disease (CWD). This is the first report on PASA detection of PrP(Sc) from the urine of naturally or preclinical prion-diseased ovine or cervids. Detection was achieved by using the surround optical fiber immunoassay (SOFIA) to measure the products of limited serial protein misfolding cyclic amplification (sPMCA). Conversion of PrP(C) to PrP(Sc) was not influenced by the presence of poly(A) during sPMCA or by the homogeneity of the PrP genotypes between the PrP(C) source and urine donor animals. Analysis of the sPMCA-SOFIA data resembled a linear, rather than an exponential, course. Compared to uninfected animals, there was a 2- to 4-log increase of proteinase K-sensitive, light chain immunoglobulin G (IgG) fragments in scrapie-infected sheep but not in infected CWD-infected deer. The higher-than-normal range of IgG levels found in the naturally and experimentally infected clinical scrapie-infected sheep were independent of their genotypes. Although analysis of urine samples throughout the course of infection would be necessary to determine the usefulness of altered IgG levels as a disease biomarker, detection of PrP(Sc) from PASA in urine points to its potential value for antemortem diagnosis of prion diseases.

• In vivo comparison of chronic wasting disease infectivity from deer with variation at prion protein residue 96.

  Authors: Brent Race, Kimberly Meade-White, Michael W Miller, Karen A Fox, Bruce Chesebro

  Journal of virology. 06/2011; 85(17):9235-8.

  Chronic wasting disease (CWD) is a prion disease of cervids that causes neurodegeneration and death. Susceptibility to prion infections, including CWD, can be dependent on the amino acid sequence ofChronic wasting disease (CWD) is a prion disease of cervids that causes neurodegeneration and death. Susceptibility to prion infections, including CWD, can be dependent on the amino acid sequence of the host prion protein (PrP). Here, CWD agent obtained from a deer expressing the 96SS genotype, associated with partial resistance to CWD, was used to infect transgenic (tg) mice expressing either 96GG or 96SS deer PrP. Transgenic mice expressing 96GG deer PrP succumbed to this agent, but tg mice expressing 96SS deer PrP did not. Additional studies using inocula from 96GG deer showed no transmission to 96SS PrP mice and delayed disease in 96GS mice. Thus, 96S PrP played an inhibitory role in disease progression in tg mice.

• Soil clay content underlies prion infection odds.

  Authors: W David Walter, Daniel P Walsh, Matthew L Farnsworth, Dana L Winkelman, Michael W Miller

  Nature communications. 02/2011; 2:200.

  Environmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases. Because binding to montmorillonite (an aluminosilicateEnvironmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases. Because binding to montmorillonite (an aluminosilicate clay mineral) or clay-enriched soils had been shown to enhance experimental prion transmissibility, we hypothesized that prion transmission among mule deer might also be enhanced in ranges with relatively high soil clay content. In this study, we report apparent influences of soil clay content on the odds of prion infection in free-ranging deer. Analysis of data from prion-infected deer herds in northern Colorado, USA, revealed that a 1% increase in the clay-sized particle content in soils within the approximate home range of an individual deer increased its odds of infection by up to 8.9%. Our findings suggest that soil clay content and related environmental properties deserve greater attention in assessing risks of prion disease outbreaks and prospects for their control in both natural and production settings.

• The role of predation in disease control: a comparison of selective and nonselective removal on prion disease dynamics in deer.

  Authors: Margaret A Wild, N Thompson Hobbs, Mark S Graham, Michael W Miller

  Journal of wildlife diseases. 01/2011; 47(1):78-93.

  Effective measures for controlling chronic wasting disease (CWD), a contagious prion disease of cervids, remain elusive. We review theoretic relationships between predation and host-parasite dynamicsEffective measures for controlling chronic wasting disease (CWD), a contagious prion disease of cervids, remain elusive. We review theoretic relationships between predation and host-parasite dynamics and describe a mathematical model to evaluate the potential influence of random removal through harvest or culling and selective predation by wolves (Canis lupus) upon CWD dynamics in deer (Odocoileus spp.) populations. Imposing nonselective mortality representing a 15% annual harvest or cull 51 yr after CWD introduction lowered both deer population size and steady state CWD. Selective (4×) mortality at the same 15% predation rate caused a more modest reduction in deer population size accompanied by a relatively rapid decline in CWD prevalence and elimination of the disease from a closed population. The impacts of selective predation on epidemic dynamics were sensitive to assumptions on parameter estimates; however, within expected ranges, the results of selective predation were consistent and robust. We suggest that as CWD distribution and wolf range overlap in the future, wolf predation may suppress disease emergence or limit prevalence.

• Estimating chronic wasting disease effects on mule deer recruitment and population growth.

  Authors: Jessie Dulberger, N Thompson Hobbs, Heather M Swanson, Chad J Bishop, Michael W Miller

  Journal of wildlife diseases. 10/2010; 46(4):1086-95.

  Chronic wasting disease (CWD), a prion disease of mule deer (Odocoileus hemionus), accelerates mortality and in so doing has the potential to influence population dynamics. Although effects on muleChronic wasting disease (CWD), a prion disease of mule deer (Odocoileus hemionus), accelerates mortality and in so doing has the potential to influence population dynamics. Although effects on mule deer survival are clear, how CWD affects recruitment is less certain. We studied how prion infection influenced the number of offspring raised to weaning per adult (≥2 yr old) female mule deer and subsequently the estimated growth rate (λ) of an infected deer herd. Infected and presumably uninfected radio-collared female deer were observed with their fawns in late summer (August-September) during three consecutive years (2006-2008) in the Table Mesa area of Boulder, Colorado, USA. We counted the number of fawns accompanying each female, then used a fully Bayesian model to estimate recruitment by infected and uninfected females and the effect of the disease on λ. On average, infected females weaned 0.95 fawns (95% credible interval=0.56-1.43) whereas uninfected females weaned 1.34 fawns (95% credible interval=1.09-1.61); the probability that uninfected females weaned more fawns than infected females was 0.93). We used estimates of prevalence to weight recruitment and survival parameters in the transition matrix of a three-age, single-sex matrix model and then used the matrix to calculate effects of CWD on λ. When effects of CWD on both survival and recruitment were included, the modeled λ was 0.97 (95% credible interval = 0.82-1.09). Effects of disease on λ were mediated almost entirely by elevated mortality of infected animals. We conclude that although CWD may affect mule deer recruitment, these effects seem to be sufficiently small that they can be omitted in estimating the influences of CWD on population growth rate.

• A bighorn sheep die-off in southern Colorado involving a Pasteurellaceae strain that may have originated from syntopic cattle.

  Authors: Lisa L Wolfe, Brandon Diamond, Terry R Spraker, Michael A Sirochman, Daniel P Walsh, Chandra M Machin, Donald J Bade, Michael W Miller

  Journal of wildlife diseases. 10/2010; 46(4):1262-8.

  We investigated a pasteurellosis epizootic in free-ranging bighorn sheep (Ovis canadensis) wherein a Pasteurellaceae strain carried by syntopic cattle (Bos taurus) under severe winter conditionsWe investigated a pasteurellosis epizootic in free-ranging bighorn sheep (Ovis canadensis) wherein a Pasteurellaceae strain carried by syntopic cattle (Bos taurus) under severe winter conditions appeared to contribute to pneumonia in affected bighorns. Twenty-one moribund or dead bighorn sheep were found on the "Fossil Ridge" herd's winter range, Colorado, USA, between 13 December 2007 and 29 February 2008. Eight carcasses examined showed gross or microscopic evidence of acute to subacute fibrinous bronchopneumonia. All eight carcasses yielded at least one β-hemolytic Mannheimia haemolytica biogroup 1(±(G)) strain, and seven also yielded a β-hemolytic Bibersteinia trehalosi biogroup 4 (CDS) strain; evidence of Pasteurella multocida, Mycoplasma ovipneumoniae, and parainfluenza 3 and bovine respiratory syncytial viruses was also detected. Isolates of β-hemolytic Manneimia haemolytica biogroup 1(G) from a bighorn carcass and a syntopic cow showed 99.5% similarity in genetic fingerprints; B. trehalosi biogroup 4(CDS) isolates were ≥94.9% similar to an isolate from a nearby bighorn herd. Field and laboratory observations suggested that pneumonia in affected bighorns may have been caused by a combination of pathogens including two pathogenic Pasteurellaceae strains--one likely of cattle origin and one likely of bighorn origin--with infections in some cases perhaps exacerbated by other respiratory pathogens and severe weather conditions. Our and others' findings suggest that intimate interactions between wild sheep and cattle should be discouraged as part of a comprehensive approach to health management and conservation of North American wild sheep species.

• Asymptomatic deer excrete infectious prions in faeces.

  Authors: Gültekin Tamgüney, Michael W Miller, Lisa L Wolfe, Tracey M Sirochman, David V Glidden, Christina Palmer, Azucena Lemus, Stephen J DeArmond, Stanley B Prusiner

  Nature. 07/2010; 466(7306):652.

• Select tissue mineral concentrations and chronic wasting disease status in mule deer from North-central Colorado.

  Authors: Lisa L Wolfe, Mary M Conner, Cathy L Bedwell, Paul M Lukacs, Michael W Miller

  Journal of wildlife diseases. 07/2010; 46(3):1029-34.

  Trace mineral imbalances have been suggested as having a causative or contributory role in chronic wasting disease (CWD), a prion disease of several North American cervid species. To begin exploringTrace mineral imbalances have been suggested as having a causative or contributory role in chronic wasting disease (CWD), a prion disease of several North American cervid species. To begin exploring relationships between tissue mineral concentrations and CWD in natural systems, we measured liver tissue concentrations of copper, manganese, and molybdenum in samples from 447 apparently healthy, adult (> or = 2 yr old) mule deer (Odocoileus hemionus) culled or vehicle killed from free-ranging populations in north-central Colorado, United States, where CWD occurs naturally; we also measured copper concentrations in brain-stem (medulla oblongata at the obex) tissue from 181 of these deer. Analyses revealed a wide range of concentrations of all three minerals among sampled deer (copper: 5.6-331 ppm in liver, 1.5-31.9 ppm in obex; manganese: 0.1-21.4 ppm in liver; molybdenum: 0.5-4.0 ppm in liver). Bayesian multiple regression analysis revealed a negative association between obex copper (-0.097; 95% credible interval -0.192 to -0.006) and the probability of sampled deer also being infected with CWD, as well as a positive association between liver manganese (0.158; 95% credible interval 0.066 to 0.253) and probability of infection. We could not discern whether the tendencies toward lower brain-stem copper concentrations or higher systemic manganese concentrations in infected deer preceded prion infection or rather were the result of infection and its subsequent effects, although the distribution of trace mineral concentrations in infected deer seemed more suggestive of the latter.

• Detection of Yersinia pestis DNA in prairie dog-associated fleas by polymerase chain reaction assay of purified DNA.

  Authors: Karen A Griffin, Daniel J Martin, Laura E Rosen, Michael A Sirochman, Daniel P Walsh, Lisa L Wolfe, Michael W Miller

  Journal of wildlife diseases. 04/2010; 46(2):636-43.

  We evaluated, refined, and applied well-established polymerase chain reaction (PCR) techniques for detecting Yersinia pestis DNA in fleas (mainly Oropsylla spp.) collected from prairie dog (CynomysWe evaluated, refined, and applied well-established polymerase chain reaction (PCR) techniques for detecting Yersinia pestis DNA in fleas (mainly Oropsylla spp.) collected from prairie dog (Cynomys spp.) burrows. Based on results from PCR of avirulent Y. pestis strain A1122 DNA, we used DNA purification and primers for the plasminogen activator gene to screen field-collected fleas. We detected Y. pestis DNA in flea pools from two black-tailed prairie dog (Cynomys ludovicianus) colonies with evidence of recent plague epizootics, and from one of four white-tailed prairie dog (Cynomys leucurus) colony complexes (Wolf Creek) where evidence of epizootic plague was lacking. Relative flea abundance and occurrence of Y. pestis DNA among flea pools appeared to vary over time at Wolf Creek. Both DNA purification and primer sequences appeared to influence the likelihood of detecting Y. pestis DNA by PCR in fleas collected from prairie dog burrows in the absence of observed epizootic plague. Presence of Y. pestis plasmid DNA in fleas collected from prairie dog burrows at Wolf Creek may represent evidence that infected fleas were somehow being maintained in that system between epizootics, consistent with the hypothesized enzootic maintenance of plague in prairie dog colony complexes elsewhere.

• A novel method for preclinical detection of PrPSc in blood.

  Authors: Richard Rubenstein, Binggong Chang, Perry Gray, Martin Piltch, Marie S Bulgin, Sharon Sorensen-Melson, Michael W Miller

  The Journal of general virology. 03/2010; 91(Pt 7):1883-92.

  In this study, we demonstrate that a moderate amount of protein misfolding cyclic amplification (PMCA) coupled to a novel surround optical fibre immunoassay (SOFIA) detection scheme can be used toIn this study, we demonstrate that a moderate amount of protein misfolding cyclic amplification (PMCA) coupled to a novel surround optical fibre immunoassay (SOFIA) detection scheme can be used to detect the disease-associated form of the prion protein (PrP(Sc)) in protease-untreated plasma from preclinical and clinical scrapie sheep, and white-tailed deer with chronic wasting disease, following natural and experimental infection. PrP(Sc), resulting from a conformational change of the normal (cellular) form of prion protein (PrP(C)), is considered central to neuropathogenesis and serves as the only reliable molecular marker for prion disease diagnosis. While the highest levels of PrP(Sc) are present in the central nervous system, the development of a reasonable diagnostic assay requires the use of body fluids that characteristically contain exceedingly low levels of PrP(Sc). PrP(Sc) has been detected in the blood of sick animals by means of PMCA technology. However, repeated cycling over several days, which is necessary for PMCA of blood material, has been reported to result in decreased specificity (false positives). To generate an assay for PrP(Sc) in blood that is both highly sensitive and specific, we have utilized limited serial PMCA (sPMCA) with SOFIA. We did not find any enhancement of sPMCA with the addition of polyadenylic acid nor was it necessary to match the genotypes of the PrP(C) and PrP(Sc) sources for efficient amplification.

• A weighted surveillance approach for detecting chronic wasting disease foci.

  Authors: Daniel P Walsh, Michael W Miller

  Journal of wildlife diseases. 01/2010; 46(1):118-35.

  A key component of wildlife disease surveillance is determining the spread and geographic extent of pathogens by monitoring for infected individuals in regions where cases have not been previouslyA key component of wildlife disease surveillance is determining the spread and geographic extent of pathogens by monitoring for infected individuals in regions where cases have not been previously detected. A practical challenge of such surveillance is developing reliable, yet cost-effective, approaches that remain sustainable when monitoring needs are prolonged or continuous, or when resources to support these efforts are limited. In order to improve the efficiency of chronic wasting disease (CWD) surveillance in Colorado, United States, we developed a weighted surveillance system exploiting observed differences in CWD prevalence across demographic strata within infected mule deer (Odocoileus hemionus) populations. We used field data to estimate sampling weights for individuals from eight demographic strata distinguished by differences in apparent health, sex, and age. In this system, individuals from a sample source with high prevalence and low inclusion probability (e.g., clinical CWD "suspects") received >or=10.3 times more weight than those from a source with low prevalence and high inclusion probability (e.g., apparently healthy, hunter-harvested individuals). We simulated use of this alternative surveillance system for a deer management unit in Colorado and evaluated the potential effects of using biased weights on the probability of failing to detect CWD and on relative surveillance costs. We found that this system should be transparent, cost-effective, and reasonably robust to the inadvertent use of biased weights. By implementing this, or a similar, weighted surveillance system, wildlife agencies should be able to maintain or improve current surveillance standards while, perhaps, collecting and examining fewer samples, thereby increasing the efficiency and cost-effectiveness of ongoing CWD surveillance programs.

• Mountain lions prey selectively on prion-infected mule deer.

  Authors: Caroline E Krumm, Mary M Conner, N Thompson Hobbs, Don O Hunter, Michael W Miller

  Biology letters. 10/2009;

  The possibility that predators choose prey selectively based on age or condition has been suggested but rarely tested. We examined whether mountain lions (Puma concolor) selectively prey upon muleThe possibility that predators choose prey selectively based on age or condition has been suggested but rarely tested. We examined whether mountain lions (Puma concolor) selectively prey upon mule deer (Odocoileus hemionus) infected with chronic wasting disease, a prion disease. We located kill sites of mountain lions in the northern Front Range of Colorado, USA, and compared disease prevalence among lion-killed adult (>/=2 years old) deer with prevalence among sympatric deer taken by hunters in the vicinity of kill sites. Hunter-killed female deer were less likely to be infected than males (odds ratios (OR) = 0.2, 95% confidence intervals (CI) = 0.1-0.6; p = 0.015). However, both female (OR = 8.5, 95% CI = 2.3-30.9) and male deer (OR = 3.2, 95% CI = 1-10) killed by a mountain lion were more likely to be infected than same-sex deer killed in the vicinity by a hunter (p < 0.001), suggesting that mountain lions in this area actively selected prion-infected individuals when targeting adult mule deer as prey items.

• Surround optical fiber immunoassay (SOFIA): an ultra-sensitive assay for prion protein detection.

  Authors: Binggong Chang, Perry Gray, Martin Piltch, Marie S Bulgin, Sharon Sorensen-Melson, Michael W Miller, Paul Davies, David R Brown, Daniel R Coughlin, Richard Rubenstein

  Journal of virological methods. 08/2009; 159(1):15-22.

  We describe the development of a new technology (SOFIA) and demonstrate its utility by establishing a sensitive and specific assay for PrP(Sc). SOFIA is a surround optical fiber immunoassay which isWe describe the development of a new technology (SOFIA) and demonstrate its utility by establishing a sensitive and specific assay for PrP(Sc). SOFIA is a surround optical fiber immunoassay which is comprised of a set of specific monoclonal antibodies and comprehensive capture of high energy fluorescence emission. In its current format, this system is capable of detecting less than 10 attogram (ag) of hamster, sheep and deer recombinant PrP. Approximately 10 ag of PrP(Sc) from 263 K-infected hamster brains can be detected with similar lower limits of PrP(Sc) detection from the brains of scrapie-infected sheep and deer infected with chronic wasting disease. These detection limits allow protease treated and untreated material to be diluted beyond the point where PrP(C), non-specific proteins or other extraneous material may interfere with PrP(Sc) signal detection and/or specificity. This not only eliminates the issue of specificity of PrP(Sc) detection but also increases sensitivity since the possibility of partial PrP(Sc) proteolysis is no longer a concern. SOFIA will likely lead to early antemortem detection of transmissible encephalopathies and is also amenable for use with additional target amplification protocols. SOFIA represents a sensitive means for detecting specific proteins involved in disease pathogenesis and/or diagnosis that extends beyond the scope of the transmissible spongiform encephalopathies.

• Effects of selenium supplementation and sample storage time on blood indices of selenium status in bighorn sheep.

  Authors: Laura E Rosen, Daniel P Walsh, Lisa L Wolfe, Cathy L Bedwell, Michael W Miller

  Journal of wildlife diseases. 08/2009; 45(3):795-801.

  Periodic pneumonia outbreaks cause large-scale die-offs that threaten the viability of bighorn sheep (Ovis canadensis) populations. Bighorns are highly susceptible to pneumonia, and in some casesPeriodic pneumonia outbreaks cause large-scale die-offs that threaten the viability of bighorn sheep (Ovis canadensis) populations. Bighorns are highly susceptible to pneumonia, and in some cases this susceptibility may be exacerbated by trace mineral deficiencies. To evaluate responses to injectable selenium supplementation, eight captive bighorn sheep were treated with either an injectable sodium selenite supplement or a saline control. We collected 6-ml blood aliquots before and at 1, 6, and 12 wk posttreatment. We submitted one set of aliquots immediately to measure selenium (Se) and zinc (Zn) concentrations and glutathione-peroxidase (GSH-Px) activity; additional aliquots were held at about 22 C and then submitted at 1, 3, and 7 days postcollection to assess effects of storage on these measures. Neither Se nor GSH-Px were affected by selenite injections. Both Se and GSH-Px demonstrated small linear decays over the 7-day storage period (0.011 ppm/day [SE=0.0027] and 15.78 mmole/l/sec/day [SE=6.88], respectively); in contrast, Zn concentrations in stored samples increased logarithmically (0.35 ppm/day on the natural log scale). Blood Se and GSH-Px were not correlated in sampled bighorns; however, because all values for both measures were within normal limits, lack of correlation did not affect interpretation of these data in our study.