Brucellosis In Elk Research Articles

The Emotional Dimensions of Animal Disease Management: A Political Ecology Perspective for a Time of Heightened Biosecurity

The ongoing devastation of the Covid-19 pandemic has brought new urgency to questions surrounding the origins, management, and complex dynamics of infectious diseases. In this mini review, we use growing international concern over the pandemic potential of emerging infectious diseases as motivation for outlining a research approach to study the emotional dimensions of animal disease management. We sketch out this important analytical terrain by first locating opportunities for literature on the biosecurization of nature to intersect with the emerging field of emotional political ecology. Second, we describe three biosecurity contexts and environmental conflicts at the wildlife-livestock interface: African swine fever in wild boar, brucellosis in elk, and pneumonia in bighorn and domestic sheep. We argue that in these “contact zones,” a focus on emotions can add a new layer of explanation for analyzing the manifestations, implications, and varied experiences of biosecurity.

Parsing the effects of demography, climate and management on recurrent brucellosis outbreaks in elk

Abstract Zoonotic pathogens can harm human health and well‐being directly or by impacting livestock. Pathogens that spillover from wildlife can also impair conservation efforts if humans perceive wildlife as pests. Brucellosis, caused by the bacterium Brucella abortus, circulates in elk and bison herds of the Greater Yellowstone Ecosystem and poses a risk to cattle and humans. Our goal was to understand the relative effects of climatic drivers, host demography and management control programmes on disease dynamics. Using >20 years of serologic, demographic and environmental data on brucellosis in elk, we built stochastic compartmental models to assess the influences of climate forcing, herd immunity, population turnover and management interventions on pathogen transmission. Data were collected at feedgrounds visited in winter by free‐ranging elk in Wyoming, USA. Snowpack, hypothesized as a driver of elk aggregation and thus brucellosis transmission, was strongly correlated across feedgrounds. We expected this variable to drive synchronized disease dynamics across herds. Instead, we demonstrate asynchronous epizootics driven by variation in demographic rates. We evaluated the effectiveness of test‐and‐slaughter of seropositive female elk at two feedgrounds. Test‐and‐slaughter temporarily reduced herd‐level seroprevalence but likely reduced herd immunity while removing few infectious individuals, resulting in subsequent outbreaks once the intervention ceased. We simulated an alternative strategy of removing seronegative female elk and found it would increase herd immunity, yielding fewer infections. We evaluated a second experimental treatment wherein feeding density was reduced at one feedground, but we found no evidence for an effect despite a decade of implementation. Synthesis and applications. Positive serostatus is often weakly correlated with infectiousness but is nevertheless used to make management decisions including lethal removal in wildlife disease systems. We show how this can have adverse consequences whereas efforts that maintain herd immunity can have longer‐term protective effects. Climatic drivers may not result in synchronous disease dynamics across populations unless vital rates are also similar because demographic factors have a large influence on disease patterns.

PARTIAL PROTECTION IN BALB/C HOUSE MICE (MUS MUSCULUS) AND ROCKY MOUNTAIN ELK (CERVUS CANADENSIS) AFTER VACCINATION WITH A KILLED, MUCOSALLY DELIVERED BRUCELLA ABORTUS VACCINE

Brucellosis, caused by Brucella abortus, has been eliminated from livestock in the US. Remaining wildlife reservoirs are the bison (Bison bison) and elk (Cervus canadensis) populations in Yellowstone National Park and the surrounding area, from which there is periodic exposure and transmission to surrounding livestock herds. Elk account for nearly all of the livestock exposure, and the infection appears to be expanding in the elk population. Currently, there are no known effective vaccines for brucellosis in elk. We conducted three experiments to evaluate the efficacy and practicality of delivering a killed B. abortus vaccine compounded with montmorillonite clay as a carrying agent to oral, nasal, and conjunctival mucosa. The first study, conducted in laboratory mice (Mus musculus), demonstrated protection against infection equal to that produced by the currently approved cattle (Bos taurus) vaccine RB51. The second experiment, conducted as a pilot study in a small sample of elk, demonstrated partial protection against B. abortus infection. Results of the third experiment showed that elk consumed the majority of a surrogate vaccine compounded with montmorillonite mixed in hay with oral, nasal, conjunctival, and gastrointestinal exposure to the vaccine. These results suggest that multiple exposures to a mucosally delivered vaccine may provide an effective method of vaccinating wildlife.

국내 가축에서 브루셀라병에 대한 혈청학적 모니터링

(Received: July 23, 2014; Revised: September 16, 2014; Accepted: October 13, 2014)Abstract : In Korea, brucellosis has been reported periodically in cattle and rarely in dogs; however, it has not previouslybeen screened in domestic animals such as elk, pigs and goats. To investigate the serological prevalence, serum sampleswere taken from the aforementioned animals annually during 2007-2013 and screened by the rose-bengal test (RBT)or modified RBT, after which positive sera were evaluated by the standard tube agglutination test (STAT). Finally,RBT and STAT-positive sera were confirmed by competitive-ELISA. Brucella abortus biovar 1 was isolated from threeelk that were shown to be positive serologically in 2008. There was no evidence of brucellosis in pigs. Based onserological monitoring and investigation of etiological agents, there is no evidence of outbreak of brucellosis in elk,pigs or goats of Korea since 2008. However, the possibility for brucellosis from cattle to affect these other livestockexists; therefore, extensive and continuous serological monitoring is required to maintain their brucellosis-free status.Keywords : brucellosis, competitive-ELISA, rose-Bengal test, serological test, standard tube agglutination test

Combining and comparing multiple serial dilution assays of particles in solution: application to brucellosis in elk of the Greater Yellowstone Ecosystem

The concentration detection threshold (CDT) is the concentration of particles in solution beyond which a (serial dilution) assay detects particle presence. By our account, CDTs typically are not estimated but are fixed at some value. Setting a CDT to zero (\(d=0\)) implies perfect detection, a common assumption, and setting \(d>0\) gives results that are “denominated” in units of \(d\), i.e., are relative to the choice of \(d\). Using multiple, different serial dilution assays, each with its own CDT, we choose a “reference assay,” to which we assign a fixed CDT value, to obtain relative estimates of the remaining assays’ CDTs and the underlying particle concentration. We present the CDTs as a novel way to account for or to compare different serial dilution assays, “sensitivities”. We apply our methodology to data from four assays of the presence of bacterial (B. abortus) antibodies in the serum of elk in the Greater Yellowstone Ecosystem, where transmission of brucellosis—the disease ensuing from infection—to commercial livestock is managed by the Wyoming Game and Fish Department to avoid the primary symptom of abnormal fetal abortion. Results agree qualitatively with the more traditional notion of sensitivity as the true positive rate.

Identification of Brucella abortus genes in elk (Cervus elaphus) using in vivo-induced antigen technology (IVIAT) reveals novel markers of infection

Elk in the Greater Yellowstone Area are a major reservoir for brucellosis, which represents an obstacle to eradication of the disease in domestic livestock. Furthermore, immune responses to Brucella abortus infection in the wild host are not well-understood. In this regard, in vivo-induced antigen technology (IVIAT) was employed to identify novel B. abortus antigens expressed during infection in elk. Sera collected from sero-positive Wyoming elk were pooled and absorbed against in vitro-grown cultures of B. abortus. Approximately 35,000 E. coli clones, expressing B. abortus DNA, were then screened by colony immunoblot, yielding ten genes with immuno-reactive products, to include seven proteins secreted beyond the inner membrane. Three products, an outer membrane protein (D15), malate dehydrogenase (Mdh), and an ion transporter (AfuA), were examined by Western blot against individual elk serum samples. Sero-reactivity was significantly more frequent for both Mdh and D15 in naturally infected animals, compared to vaccinated and uninfected elk, indicating that antibody to these two antigens is a predictor of natural infection. Cross-reactivity of all three proteins was next examined with serum samples from confirmed brucellosis-positive cattle. While variable patterns of reactivity were seen with the antigens, the sample group was equivalently reactive to AfuA and Mdh, compared to elk, suggesting that these antigens are commonly expressed during infection in both hosts. We conclude that the application of IVIAT to B. abortus may not only facilitate the identification of serologic markers for brucellosis in elk, but may provide further insight into biological processes of the pathogen in different hosts.

EFFECTS OF MANAGEMENT AND CLIMATE ON ELK BRUCELLOSIS IN THE GREATER YELLOWSTONE ECOSYSTEM

Every winter, government agencies feed approximately 6000 metric tons (6 x 10(6) kg) of hay to elk in the southern Greater Yellowstone Ecosystem (GYE) to limit transmission of Brucella abortus, the causative agent of brucellosis, from elk to cattle. Supplemental feeding, however, is likely to increase the transmission of brucellosis in elk, and may be affected by climatic factors, such as snowpack. We assessed these possibilities using snowpack and feeding data from 1952 to 2006 and disease testing data from 1993 to 2006. Brucellosis seroprevalence was strongly correlated with the timing of the feeding season. Longer feeding seasons were associated with higher seroprevalence, but elk population size and density had only minor effects. In other words, the duration of host aggregation and whether it coincided with peak transmission periods was more important than just the host population size. Accurate modeling of disease transmission depends upon incorporating information on how host contact rates fluctuate over time relative to peak transmission periods. We also found that supplemental feeding seasons lasted longer during years with deeper snowpack. Therefore, milder winters and/or management strategies that reduce the length of the feeding season may reduce the seroprevalence of brucellosis in the elk populations of the southern GYE.

The Nutritional, Ecological, and Ethical Arguments Against Baiting and Feeding White-Tailed Deer

The use of food plots, supplemental feeding, and baiting has been a common and legal practice in Texas for many years. There is now controversy as to whether Texas Parks and Wildlife Department should include this extra nutrition as part of their carrying capacity estimates used to determine harvest permits for private landowners. Managers should remember that nutrition is only one component of carrying capacity, which includes water, shelter, and space as well. Extensive data exists about the potential negative impact of feeding on deer. Studies in Texas (Murden and Risenhoover 1993) have shown that fed deer (Odocoileus virginianus) can degrade rangeland by overconsuming high-quality plants and underconsuming low-quality plants. Guiterrez (1999) did not find that effect when South Texas deer were offered winter food plots. Donier et al. (1997) found in Minnesota that winter supplementation increased browse pressure within 900 m of feeders. Other reports (Williamson 2000) show increased browse pressure within a 1-mile radius of feeders, perhaps due to concentration of deer. Cooper et al. (2002) found 50% kernal home range sizes of fed deer were half that of unfed deer and that browse pressure near the feeder was 7 times that of unfed deer. Supplemental feeding has been suspected of contributing to the spread of tuberculosis in deer, chronic wasting disease in elk (Cervus canadensis) and deer, and brucellosis in elk and bison (Bison bison; Williamson 2000). Crowding due to supplemental feeding led to fighting and injuries in Michigan deer (Ozoga 1972). Feeding has actually led to starvation in deer due to increases in population when feeding was initiated (McCullough 1977, Schmitz 1990). Supplemental feed is consumed by nontarget species, possibly leading them to pass disease and to attract predators. Cooper and Ginnett (2000) found decreased survivorship of simulated turkey nests within 400 m of deer feeders in Texas. In 1998 we found illegal levels of aflatoxin in 40% of 100 randomly purchased bags of “deer corn” in Texas (N. Wilkins, Texas Cooperative Extension, USA, unpublished data). The ecological significance of deer feeding and baiting is only part of the issue. Feeding leads to ethical questions as well. Feeding is part of the domestication process, along with fencing, breeding, and health programs that, due to their expense, may lead to the desire for private ownership of wildlife. Baiting, likewise, adds to the advantages of the hunter over the hunted and may decrease hunter satisfaction and increase concerns of the antihunters and the nonhunting public (Ortega y Gasset 1995). Deer managers and agency personnel should review the data presented here and incorporate it into their decision making when considering feeding or baiting of deer.

BRUCELLOSIS IN ELK OF EASTERN IDAHO

Brucellosis occurs in free-ranging elk (Cervus elaphus) and bison (Bison bison) in the Greater Yellowstone Area, which includes portions of Idaho, Wyoming, and Montana. Brucella abortus was first detected in elk in Idaho in 1998, and from 1998 to 2002, serologic surveillance of hunter-killed elk was conducted in northeastern and southeastern Idaho. Prevalence of antibodies in these elk varied annually, but averaged between 2% and 3%. Elk were also trapped in northeastern Idaho from 1998-2002 and tested for brucellosis using serology and tissue culture. In areas where artificial feeding of elk was done, antibody prevalence ranged from 12% to 80% depending on site, age, and sex. At one feeding site (Rainey Creek), a decline in the prevalence of antibodies (from 56.8% in 1999 to 13.5% in 2002) was detected after the removal of seropositive elk over 4 yr. Seropositive elk removed from two artificial winter feeding sites (Rainey Creek and Conant Creek) were euthanized and sampled or held in captivity and allowed to calve prior to euthanasia and necropsy. At necropsy, B. abortus biovar 1 and B. abortus biovar 4 were isolated from both cows and calves; however, biovar 4 was predominant. A dual infection with both biovars was found in one calf born to a seropositive cow from which biovar 4 was isolated. Abortions (16%), stillbirths (8%), and weak calves (4%) were observed in these elk. These findings confirm the presence of brucellosis in elk in eastern Idaho and provide information on disease management options.

A Synthesis of Data, Model-Based Analyses, and Refinements of Possible Management Scenarios for Bison and Elk in the Jackson Valley

The elk and bison winter ranges in the Jackson Valley lie on a land complex consisting of Grand Teton NP (GTNP), National Elk Refuge (NER), town of Jackson, private ranches, and private housing developments. To reduce conflicts on these private lands, elk and bison are artificially fed alfalfa pellets at several feedgrounds located on the National Elk Refuge, the Gros Ventre Valley (Bridger-Teton NF), and south of the town. The concentrations of elk may be altering vegetation communities, especially riparian willow, aspen, buffaloberry, and other woody shrubs near the feedgrounds. Managers are concerned about these possible alterations. Human developments, human alterations, artificial feeding and high incidence of brucellosis in elk and bison complicate management of free-ranging ungulates in Grand Teton NP and the Jackson Valley. Managers need additional information on predicted land use changes, feeding scenarios, and ungulate-disease relations in the Jackson Valley to guide their management decisions.

Greater Yellowstone's Bison: Unraveling of an Early American Wildlife Conservation Achievement

The Greater Yellowstone region's bison-brucellosis controversy has triggered troublesome proposals giving federal and state agriculture agencies jurisdiction over wildlife to eradicate a domestic livestock disease. Many of the region's bison (Bos bison) and elk (Cervus elaphus) carry the bacterium Brucella abortus, which can cause brucellosis. Local livestock officials fear bison and elk could transmit brucellosis to domestic livestock. jeopardizing state brucellosis class-free status. However, no cases of such transmission in an open range setting have been verified scientifically. Various federal and state agencies have jurisdiction over the region's wildlife and livestock; these agencies are having real difficulty reaching consensus on how to address brucellosis in the wildlife populations. Montana and Idaho recently vested state livestock officials with jurisdiction over bison leaving Yellowstone National Park (YNP), and the U.S. Department of Agriculture's Animal, Plant, and Health Inspection Service (APHIS) has indicated it may propose regulations asserting jurisdiction over bison. An interim bison management plan, the result of a recent court settlement, provides for the National Park Service (NPS) to participate in capturing, testing, and slaughtering Yellowstone's bison, but makes no provision for addressing brucellosis in elk. The region's brucellosis problem could be adequately addressed through a risk management disease control policy rather than a costly and perhaps fruitless eradication effort. Such an approach can be implemented without the unwelcome precedent of livestock officials taking jurisdiction over wildlife.

BRUCELLOSIS IN ELK I. SEROLOGIC AND BACTERIOLOGIC SURVEY IN WYOMING

Incidence of brucellosis in elk (Cervus canadensis) on two winter feedgrounds in Wyoming was examined over a 5-year period by testing serum samples using the standard plate agglutination (SPT) buffered Brucella antigen (BBA), rivanol (Riv) and complement fixation (CFT) tests. Thirty-one percent of 1,165 elk were positive by defined criteria. Considering each test individually, only 29% (106) of 370 positive sera would have been classified as reactors by the SPT, 83% (307) by the BBA test and 86% (314) by the Riv test. The CFT would have identified 85% (267) of 332 positive samples on which it was used. Brucella abortus, type 1, was isolated from 17 of 45 elk necropsied. The SPT identified 59% (10) of these as reactors, the BBA test 94% (16) and the Riv test 88% (15). The CFT identified nine of nine (100%) on which it was used. Prevalence of sero-positive animals increased with age. Brucellosis has been present in one of the two elk herds since at least 1930, and the incidence of infection among mature females in both herds was approximately 50% during this study. No single serologic test should be relied upon to diagnose brucellosis in elk.