White-tailed deer are susceptible to the agent of sheep scrapie by intracerebral inoculation

ABSTRACT: Interspecies transmission studies afford the opportunity to better understand the potential host range and origins of prion diseases. The purpose of this experiment was to determine susceptibility of white-tailed deer to the agent of scrapie after intracerebral inoculation and to compare clinical signs and lesions to those reported for chronic wasting disease (CWD). Deer (n = 5) were inoculated with 1 mL of a 10% (wt/vol) brain homogenate derived from a sheep clinically affected with scrapie. A non-inoculated deer was maintained as a negative control. Deer were observed daily for clinical signs of disease and euthanized and necropsied when unequivocal signs of scrapie were noted. One animal died 7 months post inoculation (pi) due to intercurrent disease. Examinations of brain tissue for the presence of the disease-associated abnormal prion protein (PrPSc) by western blot (WB) and immunohistochemistry (IHC) were negative whereas IHC of lymphoid tissues was positive. Deer necropsied at 15-22 months pi were positive for scrapie by IHC and WB. Deer necropsied after 20 months pi had clinical signs of depression and progressive weight loss. Tissues with PrPSc immunoreactivity included brain (at levels of cerebrum, hippocampus, colliculus, cerebellum, and brainstem), trigeminal ganglion, neurohypophysis, retina, spinal cord, and various lymphoid tissues including tonsil, retropharyngeal and mesenteric lymph nodes, Peyer's patches, and spleen. This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by intracerebral inoculation. To further test the susceptibility of white-tailed deer to scrapie these experiments will be repeated with a more natural route of inoculation.     

Nutritional Value of Guajillo as a Component of Male White-Tailed Deer Diets

Guajillo (Acacia berlandieri Benth.) is considered a medium- to high-quality forage for both wild and domestic ruminants. However, studies have shown that guajillo contains phenolic amines and alkaloids, and condensed tannins, which may cause toxicosis and reduced fertility, intake, and nutrient digestibility. To examine the nutritional value of guajillo to white-tailed deer (Odocoileus virginianus Zimmermann) more thoroughly, we present a comparison of mixed diets of 0%, 25%, 50%, and 75% guajillo in male white-tailed deer. Four in vivo metabolism trials were completed with each diet. Dry matter intake and change in body mass did not differ among diets. Gross and digestible energy intakes did not differ among diets, whereas metabolizable energy intake decreased with increased dietary guajillo concentration. Nitrogen balance and digestibility decreased with increased dietary guajillo concentration. Urinary glucuronic acid excretion increased linearly with increased dietary guajillo concentration. Nitrogen requirements for body growth and antler development were met by diets containing < 60% guajillo, whereas energy requirements for maintenance and antler growth were met with diets containing < 20% guajillo. Therefore, concentrations of dietary guajillo < 20% will support the maintenance of white-tailed deer. The primary function of guajillo may be to facilitate maintenance of adult deer, which have fewer obligatory productive processes than young deer, during periods of drought.     

Xylazine as an immobilizing agent for captive white-tailed deer.

Xylazine, at dosages of 0.89 to 8.00 mg/kg of body weight, was injected intramuscularly by manual or projectile syringe into 68 captive white-tailed deer (Odocoileus virginianus) to facilitate handling. Of 63 deer given the intended dose, 59 were moderately to deeply sedated and immobilized. Deer began to react visibly within 0.75 to 4.25 minutes after injection. Mean induction time (+/- SD) was 5.15 +/- 4.08 minutes and mean duration of immobilization was 197.90 +/- 101.13 minutes. Other than the prolongation of immobilization at dosages larger than or equal to 3 mg/kg, these times were not significantly affected by dosage or sex of the deer. Induction times were shorter in fawns than in older deer and much shorter in freshly trapped deer than in deer that had been trapped but kept undisturbed in semidarkened pens for 6 to 48 hours or in deer that were semitame captives. Dosages as low as 0.89 mg/kg were effective, and the safety margin appeared to be at least 8 times the minimal effective dose; however, immobilized deer were frequently unable to maintain sternal recumbency and required attention throughout the period of immobilization.     

Naturally occurring tuberculosis in white-tailed deer

OBJECTIVE: To determine the distribution of lesions and extent of tissues infected with Mycobacterium bovis in a captive population of white-tailed deer. DESIGN: Cross-sectional study. ANIMALS: 116 captive white-tailed deer. PROCEDURE: Deer were euthanatized, and postmortem examinations were performed. Tissues with gross lesions suggestive of tuberculosis were collected for microscopic analysis and bacteriologic culture. Tissues from the head, thorax, and abdomen of deer with no gross lesions were pooled for bacteriologic culture. Tonsillar, nasal, oral, and rectal swab specimens, fecal samples, and samples of hay and pelleted feed, soil around feeding sites, and water from 2 natural ponds were collected for bacteriologic culture. RESULTS: Mycobacterium bovis was isolated from 14 of 116 (12%) deer; however, only 9 of 14 had lesions consistent with tuberculosis. Most commonly affected tissues included the medial retropharyngeal lymph node and lung. Five of 14 tuberculous deer had no gross lesions; however, M bovis was isolated from pooled tissue specimens from the heads of each of these deer. Bacteriologic culture of tonsillar swab specimens from 2 of the infected deer yielded M bovis. Mean (+/- SEM) age of tuberculous deer was 2.5 +/- 0.3 years (range, 0.5 to 6 years). Mycobacterium bovis was not isolated from feed, soil, water, or fecal samples. CONCLUSIONS AND CLINICAL RELEVANCE: Examination of hunter-killed white-tailed deer for tuberculosis commonly includes only the lymph nodes of the head. Results of such examinations may underestimate disease prevalence by as much as 57%. Such discrepancy should be considered when estimating disease prevalence.     

Prickly Pear Cactus Responses to Summer and Winter Fires

Prescribed fire is used to reduce size and density of prickly pear cactus (Opuntia spp.) in many rangeland ecosystems. However, effects of dormant season fires (i.e., winter fires) are inconsistent. Thus, there is increasing interest in use of growing season (summer) fires. Our objective was to evaluate effects of fire season and fire intensity on mortality and individual plant (i.e., “motte”) structure (area per motte, cladodes per motte, motte height) of brownspine prickly pear (O. phaeacantha Engelm.). The study had 4 treatments: no fire, low-intensity winter fire, high-intensity winter fire, and summer fire. Three sizes of prickly pear mottes were evaluated: small (0–20 cladodes per motte), medium (21–100), and large (101–500). At 3 years postfire, prickly pear mortality in the summer fire treatment was 100% in small mottes, 90% in medium mottes, and 80% in large mottes. Motte mortality increased in this treatment over time, especially in large mottes. Mortality from high-intensity winter fires was 29% and 19% in small and medium mottes, respectively, but no large mottes were killed. Motte mortality was < 10% in low-intensity winter fire and no-fire treatments. Summer fires reduced all motte structural variables to 0 in small mottes and nearly 0 in other motte size classes. High-intensity winter fires reduced some structural variables of medium and large mottes, but had no long-term negative effects on area per motte or cladodes per motte in surviving small mottes. Low-intensity winter fires had no long-term negative effects on motte structure in any size class. Rapid growth of mottes, and especially small mottes, in the no-fire treatment suggested that resistance to winter fires can occur rapidly.     

Experimental persistent infection with bovine viral diarrhea virus in white-tailed deer

Bovine viral diarrhea virus (BVDV) infections cause substantial economic losses to the cattle industries. Persistently infected (PI) cattle are the most important reservoir for BVDV. White-tailed deer (Odocoileus virginianus) are the most abundant species of wild ruminants in the United States and contact between cattle and deer is common. If the outcome of fetal infection of white-tailed deer is similar to cattle, PI white-tailed deer may pose a threat to BVDV control programs. The objective of this study was to determine if experimental infection of pregnant white-tailed deer with BVDV would result in the birth of PI offspring. Nine female and one male white-tailed deer were captured and housed at a captive deer isolation facility. After natural mating had occurred, all does were inoculated intranasally at approximately 50 days of pregnancy with 10(6) CCID(50) each of a BVDV 1 (BJ) and BVDV 2 (PA131) strain. Although no clinical signs of BVDV infection were observed or abortions detected, only one pregnancy advanced to term. On day 167 post-inoculation, one doe delivered a live fawn and a mummified fetus. The fawn was translocated to an isolation facility to be hand-raised. The fawn was determined to be PI with BVDV 2 by serial virus isolation from serum and white blood cells, immunohistochemistry on skin biopsy, and RT-PCR. This is the first report of persistent infection of white-tailed deer with BVDV. Further research is needed to assess the impact of PI white-tailed deer on BVDV control programs in cattle.     

Effect of yohimbine on xylazine-induced immobilization in white-tailed deer

Two groups of white-tailed deer were given IM injections of xylazine with a projectile syringe. Deer in one of the groups served as controls and did not receive any treatments other than xylazine. Deer in the other group were given yohimbine IV at various times (15 to 171 minutes) to evaluate its effect on xylazine-induced immobilization. In 5 control deer given 3.7 +/- 1.2 mg of xylazine/kg (mean +/- SD), onset of recumbency was 13 +/- 2 minutes and time to standing was 268 +/- 76 minutes. In 20 principal deer given 2.8 +/- 1.0 mg of xylazine/kg, onset of recumbency was 8 +/- 7 minutes, time to sitting after giving yohimbine was 3 +/- 4 minutes in 18 of the deer, and time to standing after giving yohimbine was 4 +/- 5 minutes in 19 of the deer. Most of these deer were still moderately sedated 30 minutes after injection of yohimbine, but none of them became reimmobilized or as deeply sedated as before the injection of yohimbine. Yohimbine also reversed the bradycardia and respiratory depression induced by xylazine.     

Bovine tuberculosis in Canadian wildlife: An updated history

Mycobacterium bovis infection in wild animals attracted little attention in Canada until the disease was almost eliminated from domestic livestock. Tuberculosis was endemic in plains bison and occurred in elk, moose, and mule deer in Buffalo National Park (BNP), Alberta during the 1920s and 1930s. Bison were moved from BNP to Wood Buffalo National Park (WBNP), where tuberculosis became, and remains, endemic in bison, posing a risk to efforts to restore bison in northern Canada. Tuberculosis was found in a white-tailed deer in Ontario in 1959, and in an infected elk near Riding Mountain National Park (RMNP), Manitoba in 1992. Intense surveillance has resulted in detection of 40 elk, 8 white-tailed deer, and 7 cattle herds infected between 1997 and 2008 in the RMNP area. The strains of M. bovis in the RMNP area are different from strains tested from cattle and bison elsewhere in Canada. Management of tuberculosis in cattle and wild animals is challenging because of uncertainty about the ecology of the disease in various species, difficulty in obtaining samples and population data from wildlife, lack of validated tests, overlapping jurisdictions and authority, and conflicting values and opinions among stakeholders.     

Winter Resource Selection by Mule Deer on the Wyoming–Colorado Border Prior to Wind Energy Development

Areas identified as winter range are important seasonal habitats for mule deer (Odocoileus hemionus) because they can moderate overwinter mortality by providing thermal cover and forage. Therefore, identifying seasonally important resources is a conservation priority, especially when sensitive areas are proposed for development. We used data collected from global positioning system (GPS) collars fitted on female mule deer (n = 19; one location every 3 h) to identify resources important during winter (23 February 2011–30 April 2011; 1 November 2011–15 January 2012) in a region spanning southern Wyoming and northern Colorado that has been proposed for wind energy development. The study period included portions of two consecutive winters but were pooled for analysis. We used methods to account for GPS biases, fractal analyses to determine perceived spatial scale, and discrete choice models and conditional logistic regression to assess resource selection prior to development (i.e., baseline data). Resource selection by female mule deer revealed similar patterns between active (0600–1800 hours) and nonactive (2100–0300 hours) periods. Deer selected most strongly for proximity to rock outcrops and shrubland and average values of slope. Deer tended to avoid roads and grasslands; all other landscape features had minimal influence on resource selection (hazard ratios near, or overlapping, 1). Using the fixed-effects coefficient estimates, we developed two spatially explicit maps that depicted probability of mule deer occurrence across the landscape. Based on an independent validation sample, each map (active and nonactive) validated well with a greater percentage of locations occurring in the two highest probability of use bins. These maps offer guidance to managing mule deer populations, conserving important seasonal habitats, and mitigating development (e.g., wind energy) in areas identified as important to mule deer.     

Light and electron microscopic comparisons of cutaneous fibromas in white-tailed and mule deer

Cutaneous fibromas of white-tailed deer (Odocoileus virginianus), when compared with normal skin of the same species, had a thinner basement membrane; thickened stratum spinosum with numerous melanocytes, desmosomes, polyribosomes, and tonofilaments; focal hyperplasia of the stratum granulosum containing numerous large, electron-dense keratohyalin granules with irregular borders and containing occasional cells with diffuse intranuclear virus particles; and a moderately thickened stratum corneum with (although rarely) small crystalline arrays of virus particles. Normal mule deer (Odocoileus hemionus) skin was structurally similar to that of the white-tailed deer. Mule deer fibromas were similar to those in white-tailed deer, except for diffuse thickening of the stratum granulosum (the cells of which contained large keratohyalin granules of various electron densities with occasional composite granules) and except for a markedly thickened stratum corneum that contained numerous intranuclear viral inclusions. In negatively stained homogenates of tumors from both deer species, viral particles resembled papillomaviruses.     

The impact of seasonal variability in wildlife populations on the predicted spread of foot and mouth disease

Modeling potential disease spread in wildlife populations is important for predicting, responding to and recovering from a foreign animal disease incursion such as foot and mouth disease (FMD). We conducted a series of simulation experiments to determine how seasonal estimates of the spatial distribution of white-tailed deer impact the predicted magnitude and distribution of potential FMD outbreaks. Outbreaks were simulated in a study area comprising two distinct ecoregions in South Texas, USA, using a susceptible-latent-infectious-resistant geographic automata model (Sirca). Seasonal deer distributions were estimated by spatial autoregressive lag models and the normalized difference vegetation index. Significant (P < 0.0001) differences in both the median predicted number of deer infected and number of herds infected were found both between seasons and between ecoregions. Larger outbreaks occurred in winter within the higher deer-density ecoregion, whereas larger outbreaks occurred in summer and fall within the lower deer-density ecoregion. Results of this simulation study suggest that the outcome of an FMD incursion in a population of wildlife would depend on the density of the population infected and when during the year the incursion occurs. It is likely that such effects would be seen for FMD incursions in other regions and countries, and for other diseases, in cases in which a potential wildlife reservoir exists. Study findings indicate that the design of a mitigation strategy needs to take into account population and seasonal characteristics.     

Diagnostic detection methods for Mycobacterium avium subsp. paratuberculosis in white-tailed deer

This study compares the results and suitability of serological testing, microscopic examination, deoxyribonucleic acid (DNA) detection, and bacterial culture for detecting Mycobacterium avium subsp. paratuberculosis (Map) infection in asymptomatic farmed white-tailed deer (WTD) (Odocoileus virginianus). Deer were classified as infected if culture slants from their feces, lymph nodes, or ileum were positive, or if a polymerase chain reaction (PCR) assay detected Map DNA in any of its tissues. Deer identified as positive by agar gel immunodiffusion (AGID) testing or enzyme-linked immunosorbent assay (ELISA) but not by bacterial culture, Ziehl-Neelsen staining, or PCR assay were classified as suspect. Culture of tissues classified 10/16 (62.5%), histopathologic examination 1/16 (6.3%), tissue smears 4/16 (25%), culture slant (CS)-PCR on feces 12/15 (80%), CS-PCR on tissue 13/16 (81.3%), and direct PCR on uncultured tissues 5/16 (31.3%) deer as infected. The ELISA classified 2/15 (13.3%) deer as positive and therefore suspect. The AGID test was negative for all deer. Fifteen of 16 deer were positive by 1 or more tests; only 1 deer was negative on all 11 assays. The CS-PCR gave superior results on antemortem fecal testing as well as postmortem tissue testing and can be recommended for improving the detection of Map in WTD at every stage of infection.     

梅花鹿食性分析中粪便分析法的研究

2010年8～9月,在天恒山大庄园鹿场采用模拟动物野外采食的方式对圈养梅花鹿进行人工饲喂实验,人为设定每次喂食的植物种类和各种植物的比例,并收集每次饲喂后排泄的粪便,以及饲喂的植物,带回实验室用粪便显微分析法进行实验室分析,找出粪便中组织碎片与动物采食量之间的关系。粪样通过浓硝酸法处理后,用频率转换法进行镜检。将每次喂食植物的实际比例与计算得到的估计比例,用SPSS软件进行两配对样本的Wilcoxon符号平均秩检验和两配对样本的符号（Sign）检验。结果表明,2种两配对样本非参数检验得到的相伴概率分别为0.794和1.000,均大于显著性水平0.05,都说明食物中植物的实际比例与计算得到的估计比例不存在显著性差异。表明粪便分析法可以准确地分析梅花鹿的食物组成比例。     

Management of indigenous North American deer at the end of the 20th century in relation to large predators and primary production

Five deer species occupy North America: caribou (3.6 x 10(6) individuals), moose (1.1 x 10(6)), white-tailed deer (28.5 x 10(6)), mule deer (5.0 x 10(6)) and wapiti (1.1 x 10(6)). Caribou characterise the north of the boreal forest and the tundra, whereas moose dominate in coniferous and mixed forests growing further south. White-tailed deer are typical of the deciduous forests of the east while mule deer replace them in the mountainous terrain of the west. Wapiti possess the smallest range, mostly adjacent to the prairies to the west. The two large obligate carnivores preying on deer show a reduced distribution: wolves are almost restricted to Canada, and cougar to the mule deer range. We determined the current status of each species with the help of a questionnaire mailed to all jurisdictions harbouring deer. Most reports of threatened populations concerned caribou whereas many jurisdictions declared overabundance of white-tailed deer and wapiti. Hunting was allowed for all species when they abounded in a jurisdiction. Hunters harvested annually 7.0 x 10(6) deer on the continent, 87% being white-tailed deer. The two species that caused most conflicts with humans had the highest harvest rate: 16-17%. In terms of biomass, white-tailed deer and wapiti yielded the highest harvests, with 55 and 39 kg x km-2 of range, respectively. The average standing biomass of deer in winter ranged between 28 kg x km-2 in Nevada to 901 kg x km-2 in Indiana. The lowest standing biomasses occurred in the boreal forest (predators), in the prairies (agriculture) and in the south-west (aridity), and the highest ones in the south-east, where only white-tailed deer is present. The current abundance of deer in North America parallels, in general, the primary production of the landscape (r2 = 0.38; P < 0.0001), but predators and human activity modify this pattern.     

Comparative cardiopulmonary effects of carfentanil-xylazine and medetomidine-ketamine used for immobilization of mule deer and mule deer/white-tailed deer hybrids.

Three mule deer and 4 mule deer/white-tailed deer hybrids were immobilized in a crossover study with carfentanil (10 microg/kg) + xylazine (0.3 mg/kg) (CX), and medetomidine (100 microg/kg) + ketamine (2.5 mg/kg) (MK). The deer were maintained in left lateral recumbency for 1 h with each combination. Deer were immobilized with MK in 230+/-68 s (mean +/- SD) and with CX in 282+/-83 seconds. Systolic, mean and diastolic arterial pressure were significantly higher with MK. Heart rate, PaO2, PaCO2, pH, and base excess were not significantly different between treatments. Base excess and pH increased significantly over time with both treatments. Both treatments produced hypoventilation (PaCO2 > 50 mm Hg) and hypoxemia (PaO2 < 60 mm Hg). PaO2 increased significantly over time with CX. Body temperature was significantly (P<0.05) higher with CX compared to MK. Ventricular premature contractions, atrial premature contractions, and a junctional escape rhythm were noted during CX immobilization. No arrhythmias were noted during MK immobilization. Quality of immobilization was superior with MK, with no observed movement present for the 60 min of immobilization. Movement of the head and limbs occurred in 4 animals immobilized with CX. The major complication observed with both of these treatments was hypoxemia, and supplemental inspired oxygen is recommended during immobilization. Hyperthermia can further complicate immobilization with CX, reinforcing the need for supplemental oxygen.     

Estradiol and progesterone metabolite concentration in white-tailed deer (Odocoileus virginianus) feces.

Assays of reproductive hormone metabolites require validation in each animal species. For validation of methodology in white-tailed deer (Odocoileus virginianus), fecal samples were collected from females that had been injected by blowgun with estradiol, progesterone, or a control substance. Analysis by radioimmunoassay revealed that estradiol and pregnanediol were more abundant fecal metabolites of estrogens and progestins than were estrone or progesterone. Peak excretion rates of estradiol and pregnanediol occurred within 12 and 24 hr of injection, respectively. Ovulation time was estimated by measuring the frequency of occurrence of eight behavior patterns, including copulation. Profiles were compiled for three deer over the course of estrus and early pregnancy for estradiol, estrone, progesterone, and pregnanediol using radioimmunoassay. Pregnanediol was excreted at concentrations about 1,000 times higher than those of the other three fecal steroid metabolites, and pregnanediol differed in concentration during estrus, the luteal phase, and early pregnancy. Consequently, a simpler enzyme immunoassay was adapted and used to measure pregnanediol levels over the course of estrus and early pregnancy for seven deer. Measurement of fecal pregnanediol is useful for monitoring reproductive events in female white-tailed deer.     

Isolation of Neospora caninum from naturally infected white-tailed deer (Odocoileus virginianus)

Attempts were made to isolate Neospora caninum from naturally infected white-tailed deer (Odocoileus virginianus). A total of 110 deer killed during the 2003 hunting season in Virginia region were used for the isolation of N. caninum. Of these, brains from 28 deer that had NAT titer of 1:200 were inoculated into interferon-gamma gene knock out (KO) mice. N. caninum was isolated from the tissues of three deer and all three isolates were mildly virulent to KO mice. Only one of the isolates could be adapted to in vitro growth. Protozoa in the tissues of KO mice reacted with N. caninum-specific polyclonal antibodies and N. caninum DNA was demonstrated in infected tissues by PCR assays; sequences of portions of the ITS-1 and gene 5 loci were identical to those in the public database. This is the first record of in vitro isolation of N. caninum from white-tailed deer and lends credence to the white-tailed deer as an intermediate host for this parasite.     

Cell mediated and humoral immune responses of white-tailed deer experimentally infected with Mycobacterium bovis

The objective of this study was to improve the understanding of immune responses of whitetailed deer (Odocoileus virginianus) infected with Mycobacterium bovis. Ten mature, female, white-tailed deer were inoculated by intratonsilar instillation of 2 x 10(3)or 2 x 10(5)colony-forming units of M. bovis. Lymphocyte proliferation and humoral response to M. bovis PPD and the M. bovis protein, MPB70 were measured. Deer were tested for exposure to M. bovis by the comparative cervical skin test. Biopsy specimens of skin test sites were examined microscopically and immunohistochemically. The comparative cervical skin test correctly identified all M. bovis -inoculated deer as exposed to M. bovis. Lymphocyte proliferative responses to MPB70 were more consistent than responses to M. bovisPPD in M. bovis -inoculated deer. Antibody responses were more prominent in deer with disseminated disease than in deer with localised disease. The cellular components of delayed-type hypersensitivity reactions at skin test sites were similar to tuberculin reactions in other species. T lymphocytes of the gamma/delta phenotype were seen in increased numbers in M. bovisPPD injection sites.