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Livestock producers and state wildlife agencies have used multiple management strategies to control bovine brucellosis in the Greater Yellowstone Area (GYA). However, spillover from elk to domestic bison and cattle herds continues to occur. Although knowledge is increasing about the location and behavior of elk in the SGYA, predicting spatiotemporal overlap between elk and cattle requires locations of livestock operations and observations of elk contact by producers. We queried all producers in a three-county area using a questionnaire designed to determine location of cattle and whether producers saw elk comingle with their animals. This information was used to parameterize a spatially-explicit risk model to estimate the number of elk expected to overlap with cattle during the brucellosis transmission risk period. Elk-cattle overlap was predicted in areas further from roads and forest boundaries in areas with wolf activity, with higher slopes, lower hunter densities, and where the cost-distance to feedgrounds was very low or very high. The model was used to estimate the expected number of years until a cattle reactor will be detected, under alternative management strategies. The model predicted cattle cases every 4.28 years in the highest risk herd unit, a higher prediction than the one case in 26 years we have observed. This difference likely indicates that ongoing management strategies are at least somewhat effective in preventing potential elk-cattle brucellosis transmission in these areas. Using this model, we can infer the expected effectiveness of various management strategies for reducing the risk of brucellosis spillover from elk to cattle.

Lyme Disease is caused by the bacterial pathogen Borrelia burgdorferi, and is transmitted by the tick-vector Ixodes scapularis. It is the most prevalent arthropod-borne disease in the United States. To determine the seroprevalence of B. burgdorferi antibodies in white-tailed deer (Odocoileus virginianus) from Texas, we analyzed serum samples (n = 1493) collected during the 2001–2015 hunting seasons, using indirect ELISA. Samples with higher sero-reactivity (0.803 and above) than the negative control group (0.662) were further tested using a more specific standardized western immunoblot assay to rule out false positives. Using ELISA, 4.7% of the samples were sero-reactive against B. burgdorferi, and these originated in two eco-regions in Texas (Edwards Plateau and South Texas Plains). However, only 0.5% of the total samples were sero-reactive by standardized western immunoblot assay. Additionally, both ELISA and standardized western immunoblot assay results correlated with an increased incidence in human Lyme Disease cases reported in Texas. This is the first longitudinal study to demonstrate fluctuation in sero-reactivity of white-tailed deer to B. burgdorferi sensu stricto antigens in southern United States. Future ecological and geographical studies are needed to assess the environmental factors governing the prevalence of Lyme Disease in non-endemic areas of the southern United States., Graphical abstract, Highlights • White-tailed deer serum samples were analyzed for anti Borrelia burgdorferi IgG. • This is the first 15-year longitudinal study reported in Texas, and provides data previously unavailable within the study of Lyme disease ecology. • White-tailed deer population density might be critical to sero-prevalence. • Further pathogenic landscape studies on Lyme disease in Texas are recommended. • Databased Lyme disease ecology models in Texas can be developed.

OBJECTIVE To compare the humoral response between sheep vaccinated with a killed-virus (KV) vaccine and those vaccinated with a modified-live virus (MLV) vaccine against bluetongue virus (BTV) serotype 17. DESIGN Randomized clinical trial followed by a field trial. ANIMALS 30 yearling crossbred ewes (phase 1) and 344 sheep from 7 Wyoming farms (phase 2). PROCEDURES In phase 1, ewes seronegative for anti-BTV antibodies received sterile diluent (control group; n = 10) or an MLV (10) or KV (10) vaccine against BTV-17 on day 0. Ewes in the KV group received a second dose of the vaccine on day 21. Ewes were bred 5 months after vaccination and allowed to lamb. Anti-BTV antibodies were measured in ewes at predetermined times after vaccination and in their lambs once at 5 to 10 days after birth. In phase 2, 248 commercial sheep were screened for anti-BTV antibodies and vaccinated with a KV vaccine against BTV-17 on day 0. Sheep seronegative for anti-BTV antibodies on day 0 (n = 90) underwent follow-up serologic testing on day 365 along with 96 unvaccinated cohorts (controls). RESULTS In phase 1, all vaccinated ewes developed anti-BTV antibodies by 14 days after vaccination and remained seropositive for 1 year; all of their lambs were also seropositive. All control ewes and lambs were seronegative. In phase 2, the prevalence of vaccinated sheep with anti-BTV antibodies 1 year after vaccination was 93% and 76% as determined by a serum neutralization assay and competitive ELISA, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Both vaccines induced antibodies against BTV-17 that persisted for at least 1 year and provided passive immunity for lambs and may be a viable option to protect sheep against disease.

Scientists have feared that emerging infectious diseases could complicate efforts to conserve rare and endangered species, but quantifying impacts has proven difficult until now. We report unexpected impacts of West Nile virus (WNv) on radio-marked greater sage-grouse (Centrocercus urophasianus), a species that has declined 45‐80% and is endangered in Canada and under current consideration for federal listing in the US. We show that WNv reduced late-summer survival an average of 25% in four radio-marked populations in the western US and Canada. Serum from 112 sage-grouse collected after the outbreak show that none had antibodies, suggesting that they lack resistance. The spread of WNv represents a significant new stressor on sage-grouse and probably other at-risk species. While managing habitat might lessen its impact on sage-grouse populations, WNv has left wildlife and public health officials scrambling to address surface water and vector control issues in western North America.

Brucellosis is a bacterial disease of cattle that has become established in elk (Cervus elaphus nelsoni) and bison (Bos bison) of the Greater Yellowstone Area. It causes pregnant elk and bison to abort, and the aborted fetus has the potential to transmit the pathogen to disease-free domestic cattle. We examined how long healthy bovine fetuses, as surrogates for aborted bison or elk fetuses, remained in the environment and could be available for contact by elk, bison, and cattle. Disease-free bovine fetuses were placed on Wyoming's National Elk Refuge, state of Wyoming elk feedgrounds, and Grand Teton National Park to simulate aborted elk or bison fetuses. We monitored the fetuses until they disappeared due to scavenging. Fetuses disappeared on average in 26.8 hours (SD=25.3 hours) from the National Elk Refuge, 40.7 hours (SD=31.1 hours) at state elk feed-grounds, and 57.5 hours (SD=48.0 hours) at Grand Teton National Park. Ninety percent of fetuses can be expected to disappear from the National E...

Tissue residues were determined after intramuscular injection of florfenicol, ceftiofur, tulathromycin, oxytetracycline, and moxidectin in 102 white-tailed deer ( Odocoileus virginianus ). At day 11, 21, and 31 post injection, only tulathromycin was detected at a level >0.01 ppm in the deer liver and muscle samples tested. Oxytetracycline was only detected in liver at day 11 post injection; no other drugs were detected in either muscle or liver at these time points.

Thiafentanil is a potent synthetic opioid anesthetic being developed for wildlife anesthesia. Thiafentanil was tested for safety and efficacy on free-ranging pronghorn (Antilocapra americana) inhabiting F. E. Warren Air Force Base in southeastern Wyoming. Pronghorn were darted with pre-measured dosages of either 4.0 or 5.0 mg of thiafentanil without (group 1) or with (group 2) the addition of 25.0 mg xylazine Seventeen pronghorn were captured in group 1 and 14 pronghorn in group 2. There were no differences between groups for capture times or physiological parameters (P ≥ 0.21). Anesthetic induction was rapid for both groups (≤ 2.7 ± 0.4 min) as was recovery after antagonism (≤ 0.7 ± 0.07 min). The dosage of thiafentanil administered was 0.10 ± 0.005 mg/kg and the dosage of xylazine was 0.56 ± 0.03 mg/kg. Anesthesia in both groups was characterized by muscle rigidity and rapid, shallow respiration. Twenty-five pronghorn were radiocollared and survived ≥21 days after capture. One adult male in group 1 died during capture. Thiafentanil was considered more effective on pronghorn than carfentanil-xylazine, ketamine-xylazine, or tiletamine-zolazepam-xylazine anesthetic regimens.