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Revisiting Brucellosis in the Greater Yellowstone Area (2017)

Chapter: 7 Management Options

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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"7 Management Options." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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7 Management Options 1. INTRODUCTION Management actions are “tools” that can be used to reduce the risk of brucellosis transmission and to mitigate the effects of infection in the Greater Yellowstone Area (GYA). This chapter provides a brief overview of various approaches that have been used and are available for stakeholders in managing the risk of B. abortus transmission. These management tools can and will need to be used in combination as part of an active adaptive management approach. 2. INCENTIVIZING RISK MITIGATION EFFORTS One way to affect change would be to provide incentives for action. In the context of managing bru- cellosis, it could either take the form of incentivizing cattle producers to undertake risk mitigating efforts and decisions, or to adjust the time or location for allowing cattle to graze on public or private lands. These two options are discussed in more detail in Chapter 8. Two other tools include adjusting govern- mental fixed rate and placement date approaches to public grazing, and an insurance approach to help protect producers against damages. These are also discussed briefly in Chapter 8, and are expanded on below. 2.1 Adjusting Governmental Fixed Rate and Placement Date Approaches Public efforts could be better aligned to encourage certain outcomes. One option would be to com- pensate cattle producers whose herds become infected in direct proportion to their risk mitigation efforts. A producer could be compensated by the government in “full” if they provide evidence that they have implemented a set of “best management practices” for reducing brucellosis risk. Conversely, if a producer is able to provide only partial evidence of “good faith behavior,” then only some proportion of compensa- tion would be available (for example, if a producer in the GYA elected to not fence off their haystacks, they may then be eligible for only a proportion of the compensation level deemed available for brucellosis based testing and damages). Indemnity claims have been used for other diseases—U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA-APHIS) has regulations to specify con- ditions for payment of indemnity claims for low pathogenic avian influenza (LPAI)—and a similar approach could also be considered as a possible tool for brucellosis. However, care will need to be taken as the core role of indemnity compensation is to encourage timely and complete reporting by reducing the economic incentive to censor information on disease events. The establishment of public grazing fees and cattle placement dates also warrants further considera- tion. Parcels vary in risk depending on their location, presence or absence of elk, and the time of year. Currently, the fixed rate (updated annually) and entry date for federal grazing makes no consideration of brucellosis risks (Rimbey and Toreel, 2011). For example, one parcel next to an elk feedground with no fences will be riskier than another that is further away with fences; however, the federal grazing rate for both parcels is the same even though the brucellosis exposure risk is different across the two parcels. This is a classic example of an economically inefficient, fixed rate pricing program that fails to reflect the dif- ferent impacts public grazing has on broader brucellosis risks in the area. The committee acknowledges 110 Prepublication Copy—Subject to Further Editorial Revision

Management Options the political challenges that may arise with a differential grazing rate system, yet the fixed rate approach fails to account for risks and external costs. Even if a differential pricing system is infeasible upon further assessment, it will be essential to restrict or adjust the placement and removal dates to reflect parcel- specific brucellosis risk. If cattle were allowed to graze on “high risk” public lands with earlier placement remaining available on “lower risk” parcels, producer actions would more directly internalize brucellosis risks currently not captured by the fixed pricing and entry date system. To date, risk categorization of public lands has yet to be clearly defined and a risk assessment is clearly needed (see Box 7-1 for an example of land managers using a risk assessment to reduce contact between Sierra Nevada bighorn sheep and domestic sheep). Federal land management agencies could stipulate risk reduction “best management practices” in exchange for the privilege of using public land grazing allotments. Although an individual producer may not view these practices as necessary or cost effective, reducing risk of transmission between elk and cat- tle in the GYA is in the public interest. Therefore this would be another area where policies could be used to incentivize best practices. By considering additional private incentives, it may be possible to encourage private action to better align with the broader, public interest. 2.2 Insurance Insurance for livestock diseases provides monetary relief to producers, as some losses (such as busi- ness interruption, welfare (feeding and care) costs for animals, and loss of markets) are not currently eli- gible for U.S. government indemnification (Grannis et al., 2004). Insurance premiums subsidies could be tied to evidence of implementing “best management practices,” a concept reflected in USDA’s recent ad- justments to HPAI indemnity payments to poultry producers (USDA-APHIS, 2016). For example, pro- ducers in the GYA could be eligible for an insurance premium discount if they wait until late June to place cattle on public lands when the risk from elk is lower. Although the concept of an insurance pro- gram is sound, there are a host of challenges to making it viable including knowledge gaps in accurately assessing risk, whether there is sufficient interest by producers, and the government’s capacity to adminis- ter and subsidize premiums (Goodwin and Smith, 2013; Reeling and Horan, 2014). Also, livestock pro- ducers tend to implement even less costly risk management strategies than expected (Goodwin and Schroeder, 1994; Pennings and Garcia, 2001; Wolf and Widmar, 2014). Information is currently lacking to assess the viability of either a new insurance program or alternative compensation program. Insurance programs are not prevalent in livestock disease prevention programs, but indemnity programs are (Hoag et al., 2006; USDA-APHIS, 2016). 3. USE OF FEEDGROUNDS Efforts to feed wildlife can range from individual efforts (such as backyard birdfeeders and baiting on private property to aid in hunting) to state sponsored programs that feed large ungulates across the western United States (Smith, 2001; Sorensen et al., 2014). Supplemental feedgrounds for elk and bison in Wyoming are some of the largest and longest operating efforts. The original intent of feedgrounds was both to buffer against starvation in severe winters (as traditional winter feed areas had been developed into cattle ranches) as well as to limit the losses of hay on private properties due to elk (Smith, 2001). A third reason for the feedgrounds is to reduce the likelihood of disease transmission by maintaining a sepa- ration between elk and cattle. However, counter to that purpose, supplemental feeding increases elk and bison aggregations and facilitates brucellosis transmission within these populations (NRC, 1998; Cross et al., 2007). Although the intent is to minimize the chance of spillover to cattle, feedgrounds may exacer- bate the problem by increasing seroprevalence in elk, not only in the southern GYA but also in other por- tions of the GYA. While there are aesthetic or philosophical arguments for or against the feedgrounds, this report confines the examination of feedgrounds to its role in either facilitating or limiting the spread of brucellosis both within and between host species as well as their potential role in the future manage- ment of brucellosis. Prepublication Copy—Subject to Further Editorial Revision 111

Revisiting Brucellosis in the Greater Yellowstone Area BOX 7-1 Land Management Risk Assessment to Reduce Disease Risks Risk assessments can be useful by allowing land managers to identify and assess risk and to evaluate management options for mitigating that risk. In the case of Sierra Nevada bighorn sheep, risk modeling was conducted to predict the effectiveness of various efforts to reduce contact between big- horn sheep and domestic sheep, which can lead to outbreaks of fatal pneumonia in bighorns (Clifford et al., 2009). Several management options were compared including trucking vs. trailing, use of guard dogs, and modified grazing times and locations. The model predicted that restricting grazing time on allotments perceived as high risk would result in a 76-82% reduction in the annual probability of a pneumonia case for the Northern area and would have the most impact on reducing risk of disease transmission (Clifford et al., 2009). In the case of brucellosis, risk modeling could also be useful for identifying the areas of highest risk for brucellosis transmission and for determining the effectiveness of modifications in grazing allot- ments to reduce contact between cattle and elk. As part of such a risk assessment, the costs associ- ated with various actions can also be compared to the level of risk reduction. The USDA Forest Service and the Bureau of Land Management could similarly undertake risk assessments to help land managers determine where and when to restrict grazing that will optimize risk reduction of brucellosis transmission from elk to bison. SOURCE: Clifford et al., 2009. Supplemental feedgrounds have exacerbated brucellosis in elk and bison, facilitated the spread of brucellosis across the GYA and increased the risk for the introduction of other diseases (such as chronic wasting disease [CWD] or bovine tuberculosis). Brucellosis isolates taken from elk and livestock outside of Yellowstone National Park had genetic ancestors from the feedgrounds rather than bison from Yellow- stone (Kamath et al., 2016). Although the current genetic data suggest that the supplemental feeding grounds likely sparked several outbreaks in distant elk populations, the rare dispersal events between populations are unlikely to maintain the high seroprevalence of the disease currently observed in many free-ranging elk populations (Cross et al., 2010a). Despite the potential drawbacks of feedgrounds, they do provide some management opportunities. First, the number of cattle outbreaks in counties with sup- plemental feedgrounds appears to be no higher than in areas without supplemental feedgrounds (Brennan, 2015). This suggests that feedgrounds may contribute to maintaining spatial separation between cattle and elk even though they exacerbate disease in the elk population. Second, feedgrounds make elk more acces- sible either for vaccination or for capture in corral traps or darting from the ground. Feedgrounds could thus be used as a test case for management action. One example is for sterilizing elk that are likely to abort (presumably young age seropositive females that may be in their first or second pregnancy), which would slow the transmission of brucellosis and subsequently reduce elk seroprevalence over time. Ecologically-oriented management actions may also help mitigate feedground associated problems. Feeding elk later in the spring tends to be associated with higher seroprevalence: an additional 30 days of feeding was associated with 2-3-fold increase in seroprevalence, as abortions and calving are more likely to occur in the spring (Cross et al., 2007). However, the winter population size at the feedgrounds was not a significant predictor of seroprevalence, which may be due to an interaction between density and timing of transmission; if so, transmission occurring later in the spring would be less dependent on feedground elk density in the winter (Maichak et al., 2009). These results have prompted the Brucellosis-Habitat- Feedground Program at the Wyoming Game and Fish Department (WGFD) to attempt to implement a test program of ending the feeding season earlier on some feedgrounds to test the causal link between the length of the feeding season and the resulting elk seroprevalence. Even if this management action is suc- cessful, it is potentially not without trade-offs. Even if elk seroprevalence declines, it is unclear whether cattle risk may be reduced because additional elk-cattle contact outside of the feeding season may occur. Thus, there may be short-term risks of local elk-cattle spillover around the feedgrounds prior to realizing the potential long-term benefits of reduced elk seroprevalence. Feeding hay in a more widely distributed 112 Prepublication Copy—Subject to Further Editorial Revision

Management Options style is another approach that has been shown to markedly reduce elk-fetus contacts (Creech et al., 2012). This treatment is being implemented on several feedgrounds, but it remains to be seen whether it results in reduced elk seroprevalence. At the time of the 1998 NRC review, brucellosis was limited to bison and the WY supplemental feedgrounds, and therefore a recommended phase-out of the feedgrounds appeared at that time to be a means toward wide-scale disease reduction in elk. This is no longer the case as elk populations distant from both bison and elk appear to maintain the infection, and management actions on feedgrounds are unlikely to have ramifications for distant elk populations (e.g., Montana elk, as well as the Cody and Clark’s Fork regions of Wyoming) given that the disease is already present in those populations. Howev- er, reductions on the feedgrounds may be beneficial for reducing potential spread to other regions, such as northeastern Utah where another supplemental feedground operates. Several non-governmental organiza- tions have argued for the complete phasing out of supplemental feedgrounds for a number of reasons, in- cluding CWD. If this were to be considered, feeding could first be curtailed at the most cattle-sensitive feedgrounds with the expectation that elk would move to less sensitive feedgrounds prior to a complete phase-out. As noted above, feedground closures are likely to have short-term costs due to the potential for increased elk-cattle contact while the seroprevalence in elk remains high, yet the long-term benefits could include reduced elk seroprevalence. Feedgrounds appear to mitigate some of the cattle risk locally while enhancing disease risks across the ecosystem (for B. abortus, CWD, and other diseases). The concentration of elk and bison on supplemental feedgrounds has been associated with a number of diseases in addition to brucellosis, which led to a recent court case against the U.S. Fish and Wildlife Service for allegedly failing in its mandate to promote “healthy” wildlife (Defenders of Wildlife et al. v. Salazar, U.S. App. D.C., No.10-1544[2011]). Over half of the adult male elk that die on the National Elk Refuge annually were infected with scabies, while only 5% of surviving adult males showed clinical signs (Smith and Anderson, 1998). In addition, the management units with feedgrounds had variable calf ratios, indicating no clear support for generally higher ratios in areas with supplemental feedgrounds (Foley et al., 2015). Elk attending the feedgrounds had higher fecal glucocorticoids (FGCs)—hormones associated with stress—than elk that were on native winter ranges (Forristal et al., 2012). These fecal glucocorticoids also appeared correlated with the local density of elk at each site. Although glucocorticoids are known to be immunosuppressive, it remains undetermined how these levels of fecal glucocorticoids relate to other factors such as disease susceptibility, survival, or recruitment. Meanwhile, results from the analysis of Brucella isolates suggests that the feedgrounds are the likely source for elk infections in other areas of the GYA, with the exception of the Paradise Valley in Montana (Kamath et al., 2016). Finally, CWD is often a major point of discussion with supplemental feeding programs (Smith, 2013). CWD is a transmissible spongiform encephalopathy that infects elk, mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), and moose (Alces alces) (Williams and Young, 1980; Williams, 2005). It can be transmitted by direct contact or indirectly via the deposition of prions in feces, saliva, and urine in the environment. Several studies suggest that these prions persist in the environment for years (Miller et al., 2004; Mathiason et al., 2006). While the prevalence of CWD in free-ranging elk tends to be much lower than in either white-tailed or mule deer, the supplemental feedgrounds may repre- sent a worst-case scenario that is more similar to the high potential for rapid spread in captive elk herds where prevalence can be quite high. CWD may have dramatic effects on the elk populations visiting the supplemental feedgrounds, but those effects are likely to occur over long timescales (e.g., 20-40 years) (Wasserberg et al., 2009; Almberg et al., 2011). 4. HUNTING OF WILDLIFE Hunting is often cited as the foundation for the system of wildlife management in North America (Heffelfinger, 2013). Un-hunted wild ungulate populations—particularly in the absence of predators or other natural mortality factors—often overpopulate their habitat to a point that negatively impacts forage production, causes detrimental changes in the ecosystem, reduces ungulate carrying capacity, and causes conflicts with humans (for example, agricultural losses and vehicular accidents) (Conover, 2001). When Prepublication Copy—Subject to Further Editorial Revision 113

Revisiting Brucellosis in the Greater Yellowstone Area ecosystem level effects are seen, reproduction may decrease and mortality increase due to competition for remaining resources (McCullough, 1979). Hunting is sustainable as long as off-take does not exceed re- productive and survival capacity of the next generations. Overhunting was the cause of severe depletion (elk deer, antelope, bighorn sheep) and near extinction (bison) of many game species in North America in the late 19th century (Heffelfinger, 2013). The distribution and abundance of wildlife can be changed by manipulating hunting pressure and its spatial distribution (Conner et al., 2007). Public hunting can be used to alter numbers of free-ranging wild ungulates (deer, elk, antelope, and bison), population densities, and sex ratios (Heffelfinger, 2013). How- ever, public hunting is not a precise tool and has significant limitations when targeting specific popula- tions, particularly if target animals are not easily identifiable in the field or are not on accessible lands. Despite initial enthusiastic cooperation by hunters, efforts to use hunting to reduce or eliminate chronic wasting disease in white-tailed deer in Wisconsin failed due to several factors including waning enthusi- asm for the program and too little progress in reducing infection rates (Jennelle et al., 2014). This demon- strates how hunting can be a limited tool for disease reduction purposes. 4.1 Hunting and Disease Control in the GYA The management of wildlife is primarily the legal responsibility of state and federal governments, and hunting of wildlife generally falls under the jurisdiction of state wildlife management agencies (Krausman, 2013). Each state sets seasons and bag limits on a herd by herd basis through Herd Manage- ment Plans (HMPs) (MDFWP, 2015; WGFD, 2015). The results of the previous year’s harvest, field ob- servations, and marking studies (otherwise known as the marked capture/recapture index) of selected herds are used to set HMP goals (MDFWP, 2015). There are instances in which hunting is allowed on federal parks and refuges. A limited elk hunt is allowed at the eastern edge of Grand Teton National Park (Consolo-Murphy, 2015). Elk and bison are taken by hunters on the National Elk Refuge, which is man- aged by U.S. Fish and Wildlife Service (USFWS). Yellowstone National Park (YNP) does not allow hunting. Hunting access is allowed on most Bureau of Land Management (BLM) and U.S. Forest Service (USFS) lands and a large portion of the GYA, while hunting on private lands is managed by their owners. Hunting could be used to reduce disease transmission risk by reducing elk populations in areas where prevalence of brucellosis is relatively high, where incidence of infection appears to be increasing, and where there is greater risk of contact with cattle. Increasing the proportion of female elk harvested yearly can help reduce elk herd numbers and the number of potentially infectious females. Late season antlerless hunts could also reduce the number of female elk numbers and proportion of infected females, decrease the herd growth rate, and possibly break up dense aggregations of elk. This has been done to some extent in Wyoming. However, it is difficult for hunters to identify and specifically target brucellosis infected elk or bison. There are also temporal (e.g., seasons), physical (e.g., weather, terrain), and legal (e.g., private lands) barriers that may limit the effectiveness of hunting as a disease control tool. A signifi- cant barrier to wider applications of hunting for brucellosis management is the complex landownership pattern that result in elk refugia forming on unhunted private lands during hunting seasons. Informational outreach, incentives, and a case for hunting as a disease control tool may need to be made. When disease transmission is correlated with host density as it is with brucellosis, disease agents may be unable to persist if densities are lowered beyond a critical threshold. In wildlife systems, however, those thresholds are difficult to define and there is countervailing evidence that merely decreasing elk population size alone may not decrease seroprevalence enough to warrant management changes (Lloyd- Smith et al., 2005; Cross et al., 2010b; Proffitt et al., 2015). A secondary benefit of hunting in areas where elk populations exceed herd management goals could be to ensure against catastrophic winter kill in years of extreme weather. Hunting is a management tool to be used with caution because increasing hunter tags at a broad regional scale may shift elk distributions to areas of limited hunter access and thus intensify conflict on private land or drive elk to unhunted (refuge) private lands. 114 Prepublication Copy—Subject to Further Editorial Revision

Management Options Blood samples can help track brucellosis exposure, and hunters are often willing to collect blood samples from harvested animals to assist wildlife management agencies. The quality of samples and the accuracy of location information have unfortunately been less than optimal for hunter-collected blood samples provided to Wyoming Game and Fish Department. Montana Fish, Wildlife, and Parks has ceased using hunter-collected blood samples in favor of samples collected from elk captured for marking and herd studies. But as seen with recent cases of brucellosis on the Montana-Wyoming border near the Big- horn Mountains, targeted hunter sampling (as opposed to general sampling) could help in monitoring bru- cellosis at the DSA border and just beyond. 4.2 Economic Considerations Hunting and harvesting elk and bison (and other wildlife) in the Greater Yellowstone ecosystem is a source of income for individuals and small businesses (USFWS, 2012). Many in Idaho, Montana, and Wyoming would even consider access to public lands for hunting a right and view the harvesting of an elk (or deer, antelope, and to a lesser extent bison) as a yearly necessity for food security. Native Americans have the legal right to harvest wildlife under various treaties (Organ, 2013). Although no hunting occurs within the boundaries of Yellowstone National Park, bison culls and hunts do occur when bison move out of YNP and into the Gardiner Valley and along the western YNP boundary. Bison that are not part of YNP herds are hunted on public and private lands in Montana and Wyoming. State game and fish departments derive a significant portion of income from hunting, with elk hunt- ing revenue being one of the largest single sources of revenue for the game and fish departments in Idaho, Montana, and Wyoming (Heffelfinger, 2013). In 2009, there were 62,620 elk-hunting licenses sold in Wyoming which resulted in $8,649,005 in license sales alone, approximately 50% of revenue for the Wyoming Game and Fish Department (WGFD). WGFD received $638 per animal, with net income to WGFD of $1,765 per animal (WGFD, 2010). During the hunting season, hunters use the full array of lo- cal business services and amenities (such as gas, food, lodging, sporting goods and equipment). In 2006, 762,000 people spent a total of $1.1 billion to take part in wildlife associated recreation in Wyoming (USFWS, 2012). Of these, 84% reported participating in wildlife watching, 13% participated in hunting, and 3% indicated other (undisclosed). Of the money spent, 44% were trip-related expenses (e.g., fuel, ho- tels). The committee received public comments from ranchers in the GYA who are part-time hunting guides and derive significant income from these activities, and ranchers also noted that they charge access fees to allow hunters on their property. It is interesting to note that for Wyoming in 2010, the aggregate gross value of cattle ranching for the entire state ($1.24 billion) is only slightly higher than the amount spent on wildlife-related recreation ($1.1 billion) (USDA-NASS, 2010). Nationwide, the money generat- ed by regulated sport hunting and the incentives it provides for wildland conservation is generally credit- ed with being the primary reason for the recovery of elk, antelope, and deer populations, and to a lesser degree bison in the last century (Heffelfinger, 2013). Therefore, a major reduction in elk numbers for bru- cellosis control could potentially be in direct conflict with the interests of state game and fish depart- ments. Intense hunting activities involving brucellosis infected bison or elk could elevate the public health risk if carcasses and offal are not removed. Approximately 50% of the bison that leave YNP and enter the Gardiner, Montana, area in late winter and are subject to intensive hunting pressure in a relatively small geographic area. Testimony and photos were provided to the committee during a public comment session noting instances in which bison carcasses were left in close proximity to populated and public areas. The failure to remove carcasses and “gut piles”—including the lymphoid organs and reproductive tracts of animals—constitutes a potential health risk to the public, domestic livestock, and companion animals. Timely removal and proper disposal of post-harvest animal remains could also help build public support for the Interagency Bison Management Plan hunts. In the past few decades, some prime hunting and ranching lands (particularly in Montana, north and northwest of Yellowstone National Park) have been purchased by individuals who do not support hunting (Haggerty and Travis, 2006). These are often large tracts of land that serve as refuges for elk and compli- Prepublication Copy—Subject to Further Editorial Revision 115

Revisiting Brucellosis in the Greater Yellowstone Area cate efforts to regulate elk numbers by hunter harvest (Haggerty and Travis, 2006; MDFWP, 2015). Elk habituating to use of private protected lands significantly compromises the ability of state wildlife agen- cies to use hunting as a tool to manage elk numbers. 5. LAND USE 5.1 Brucellosis Management Action Plans Brucellosis Management Action Plans (BMAPs) have been developed to consider a wide range of efforts aimed at addressing brucellosis in a more holistic fashion. Many of these BMAPs have been developed to address brucellosis by species (either elk or bison). For example, the Jackson elk herd BMAP states its objectives are to “maintain livestock producer viability, reduce/eliminate dependence of elk on supplemental feed, maintain established elk herd unit objectives, improve range health, and max- imize benefits to all wildlife” (WGFD, 2011). A BMAP identifies the pros and cons for various options, including fencing, habitat improvement, conservation easements, and switching from cow-calf operations to stocker operations. The BMAP also acknowledges that for any action, such decisions would be under the purview of various stakeholders including state agencies and individual producers. Land acquisition and conservation easements would involve buying or long-term leasing of land, with decision authority resting with private landowners, while transactions involving the WGFD (e.g., conservation easements) would have to proceed ultimately through the WGFD (WGFD, 2011). Land acquisition for winter range outside YNP remains a goal for many stakeholders interested in bison welfare, habitat to support the free-roaming nature of bison, and less invasive management actions. Land acquisition and deactivation of livestock grazing allotments has proven to be successful at not only providing bison with more habitat, but also in reducing risks associated with bison-livestock interactions. As has occurred under the IBMP, acquisition of bison winter range is achieved through purchase of graz- ing rights, easements, or property from land owners and livestock producers, thus providing them with economic compensation. A BMAP for the Jackson bison herd was developed by the WGFD in cooperation with the National Park Service (NPS) and the USFWS (WGFD, 2008a). The BMAP outlines efforts to conserve and im- prove habitats, minimize bison/elk conflicts with adjacent landowners, provide for a feeding program co- managed with WGFD, and a structured framework of adaptive management in collaboration with WGFD to transition from intensive supplemental winter feeding to greater reliance on natural forage. The BMAP calls for the WGFD to work with the Wyoming Livestock Board to keep bison and cattle separated through several actions, such as hazing as appropriate and fencing. It also calls for the WGFD to work with managers on the NER and USFS lands to use hunting to maintain a population objective. The BMAP also calls for habitat enhancement, shorter feeding durations, and feeding in fewer years to reduce risk of intraspecies transmission. A bison BMAP has also been developed for the Absaroka Bison Management Area to address the few bison that wander from the YNP herd and exit the eastern boundary of YNP (WGFD 2008b). This BMAP calls for many of the same management options as in the Jackson BMAP, particularly efforts to maintain separation of bison from livestock. The Interagency Bison Management Plan has been successful in managing bison, but it is not considered a BMAP as it does not directly ad- dress brucellosis. Livestock producers in the GYA have been working with federal and state management agencies to reduce risks of transmission to their herds. Management efforts are developed as part of herd management plans for the designated surveillance areas (DSAs). For their BMAP, WGFD has suggested management options for fencing the elk and bison herds away from cattle in Wyoming. WGFD has also suggested that the timing of cattle grazing on BTNF and GTNP grazing allotments be manipulated to achieve temporal and spatial separation of bison and cattle. The same principle would also apply to managing the timing of cattle grazing on allotments throughout the GYA and within the DSAs that are permitted by the USFS and the BLM. The Cody herd BMAP provides management actions to redistribute elk and reduce nega- tive impacts of land ownership on elk distributions and hunter access (WGFD, 2012). These proposed 116 Prepublication Copy—Subject to Further Editorial Revision

Management Options actions include working with landowners to maintain access for hunters to meet harvest objectives (possi- bly through an incentive program), reducing or dispersing large groups of elk adjacent to and on private lands, and preventing the comingling of elk and cattle during high risk periods which requires WGFD to cooperate with landowners to move elk away from cattle. Similar management actions would be useful throughout the broader GYA. 5.2 Biosecurity (Spatial-Temporal Separation) Biosecurity is defined as “the implementation of measures that reduce the risk of disease agents be- ing introduced and spread” (FAO, 2010). Biosecurity measures are used to prevent the entry of pathogens into a herd or farm (external biosecurity); if a pathogen is already present, biosecurity measures are used to prevent the spread of disease to uninfected animals within a herd (internal biosecurity).1 Biosecurity is one of the most important considerations in preventing brucellosis from getting into a cattle herd, espe- cially given presence of free-ranging wildlife. Biosecurity measures within the GYA are focused on external biosecurity, specifically the separation of cattle from elk and bison. Examples of practices rec- ommended by state and local agencies include fencing of haystacks, testing cattle prior to adding them to the herd, and not moving breeding stock to risky summer range until after mid-June. USDA-APHIS conducts National Animal Health Monitoring System (NAHMS) surveys that docu- ment the national adoption rates of biosecurity-related practices. The NAHMS surveys consistently find that many biosecurity measures are only partially implemented by producers despite strong, long-standing recommendations from experts. Although there is some available research that investigates necessary bi- osecurity and security practices for operations outside the GYA (Brandt et al., 2008), little is known about the factors affecting producers’ willingness to implement protective practices because literature related to brucellosis for the GYA is limited. There are estimates on the costs of implementing brucellosis preven- tion activities on a representative cow/calf-long yearling operation, which provides a break-even analysis from the producer’s perspective (Roberts et al., 2012). However, analysis is lacking that captures a ger- mane discussion of public goods and externalities for the GYA. Furthermore, the actual implementation rate of brucellosis-focused biosecurity practices in the GYA remains unknown. Cattle producers in the GYA incur additional expenses when implementing biosecurity measures, which they consider costly as “it just makes doing business in this part of the world much harder” (Lundquist, 2014; Rice, 2015). The costs and benefits of implementing a specific biosecurity measure may vary across producers, yet this has not been fully documented. For instance, a producer bordering an elk feedground faces different private benefits while a producer with more “home ranch” summer range options faces lower costs of delaying movement of cattle onto higher risk, external summer range. More- over, the impact of a given producer’s actions on other producers is not well documented yet is critical to understand (Peck, 2010). This ties directly to externalities and the need for a broader bioeconomic model- ing that considers more than just private aspects of these decisions (see chapter 8 on bioeconomics). 7. ZONING USING DESIGNATED SURVEILLANCE AREAS The Brucellosis Eradication Program formerly relied on a state-by-state approach (defined by geo- political areas and boundaries) for classifying brucellosis status in the United States. States with no cases of brucellosis in livestock (zero prevalence) for at least a year with documented surveillance were classi- fied as “Class Free” states. Interstate movement requirements and associated testing costs to producers became less burdensome as a state’s status was upgraded (9 CFR Part 78, 2006). This approach worked well because there was an incentive for livestock producers to work with states to eliminate brucellosis and thus reduce or eliminate costs associated with testing. All 50 states were briefly recognized as free of 1 When applied to biosecurity, the modifiers “internal” and “external” biosecurity differ from economic concepts of internal and external economic impacts as further described in Chapter 8. Prepublication Copy—Subject to Further Editorial Revision 117

Revisiting Brucellosis in the Greater Yellowstone Area brucellosis in 2009. It was then recognized that the identification of only a few cases of brucellosis in livestock in a small geographic area, such as the GYA, could result in loss of Class Free status for the en- tire state. Increased testing costs associated with loss of status would then be unnecessarily and ineffi- ciently borne by all producers, even though the majority of the cattle herds resided in low risk areas of the state far from the risk of infection. Politically challenging surveillance and disease control approaches were often quickly implemented in an effort to regain statewide Class Free status. DSAs were introduced by USDA-APHIS in a 2009 concept paper as a zoning approach for address- ing brucellosis, and were implemented in a 2010 interim rule (USDA-APHIS, 2009; 75 Federal Register 81090 [2010]). A regionalization approach that defines brucellosis risk areas and is consistent with OIE standards creates several advantages, including the ability to focus resources specifically in high risk areas and increased flexibility in modifying the boundaries of the disease management area to reflect changes in risk while still assuring trading partners of the brucellosis-free status for the remainder of the country. The success of the DSA concept relies on at least two important surveillance streams. First, it is de- pendent on adequate surveillance in wildlife. The DSA encompasses areas with endemic brucellosis in wildlife populations, thus surveillance on the DSA perimeter will need to be adequate to delineate the ar- ea of risk to livestock species and determine the appropriate boundaries for the DSA. With financial sup- port from USDA, state wildlife and animal health agencies cooperate to conduct surveillance in wildlife. Secondly, the concept of zoning relies on sufficient surveillance to detect brucellosis in livestock within and leaving the DSA. Adult breeding cattle are tested as they leave the DSA or as they change ownership within the DSA, but there are exceptions in some states for livestock consigned to slaughter. State animal health agencies are responsible for designating the boundaries of their DSA and de- scribing their rationale via a Brucellosis Management Plan (BMP) that is subsequently approved by USDA. Idaho, Montana, and Wyoming have BMPs, yet have varied approaches in meeting these two crit- ical surveillance needs. DSA testing requirements have led to the disclosure of sixteen herds with brucel- losis in the GYA since the DSAs were implemented. Each of the GYA states has consequently adjusted their DSA boundaries at least once since initial designation because of seropositive elk. The lack of uniformity in how states conduct surveillance, determine appropriate expansion of DSAs, and enforce DSA boundaries may be a hindrance to rapid identification and adequate mitigation of infection. As pre- viously mentioned in Chapter 5, these and other gaps in the management of animals leaving the DSA will need to be addressed for the regionalization approach to be effective in addressing brucellosis (USDA- APHIS, 2012). 8. TEST AND REMOVE Testing and removal of brucellosis seropositive animals is a critical component of a strategy for eliminating brucellosis from an affected population. Test and remove is one of many tools and has been used in a variety of ways and to various degrees of success; however, it is rarely effective if used alone. To reduce the possibility of transmission, seropositive animals in an affected population would need to be removed from the herd and maintained separately from negative animals, or removed to either slaughter, research, or to a properly monitored quarantined feedlot, if available. The failure to remove seropositive animals likely results in continued transmission and an inability to control the disease. A major factor to reduce exposure and transmission of brucellosis is detecting and removing infected cows prior to parturi- tion (Nielsen and Duncan, 1990). High-risk animals, such as exposed bred heifers, are sometimes re- moved as part of a brucellosis elimination strategy to ensure they do not seroconvert and continue to spread the disease. In addition, highly susceptible seronegative animals are sometimes maintained sepa- rately to prevent exposure and subsequent infection. In livestock populations, testing and removal alone without any other disease mitigation efforts— and especially testing and removal without consideration of the time of calving and abortion—has not proven to be an effective strategy (Caetano et al., 2016). However, testing and removing seropositive an- imals is an effective tool when property utilized as part of a disease control or elimination strategy. Three 118 Prepublication Copy—Subject to Further Editorial Revision

Management Options major strategies have been demonstrated as effective tools to control brucellosis in livestock when used in combination with other tools: (1) strict biosecurity at the farm level, including herd management to mini- mize the risk of contact with viable Brucella (such as calving management, separating replacement heif- ers and managing them as a separate unit, increasing biosecurity so as to protect herds from purchasing infected animals or becoming infected from community herds, and utilizing cleaning and disinfecting when appropriate to minimize environmental contamination); (2) vaccination; and (3) testing and removal programs (Pérez-Sancho et al., 2015). In the United States, considerable progress was made toward eliminating brucellosis from cattle by replacing blind test and slaughter methods of the 1970s with the development of individual herd plans (Adams, 1990). These herd plans included the use of additional disease mitigation actions, such as vac- cination and separation of high risk animals to reduce transmission and limit exposure of naïve animals. Vaccination alone is insufficient to eradicate brucellosis, but it increases resistance to infection and it re- duces both the risk of abortions and excretion of Brucella (European Commission, 2009). The key to suc- cess, however, is to test and rapidly remove infected animals before they have the opportunity to continue to transmit the disease (PAHO, 2001). In some countries, when the prevalence of brucellosis is high or socioeconomic resources are lim- ited, mass vaccination is the most suitable tool for the initial control of the disease (Pérez-Sancho et al., 2015). In those cases, systemic and mandatory vaccination is used to reduce infection rate to a level where testing and removal can then be used to eradicate the disease. For brucellosis, it is estimated that 7-10 years of systemic vaccination are necessary to achieve this objective (PAHO, 2001). In several cases with both privately and publicly owned bison herds, a testing and removal strategy has been used in combination with other management actions to eliminate brucellosis. In combination with vaccination, the test and remove strategy has been effectively used for brucellosis in bison in the fol- lowing six cases: 1. Test and removal, combined with vaccination, was previously used in Yellowstone National Park in the early 1900’s, and reduced the seroprevalence of bison from 62% to 15% in 2 years (Coburn, 1948). 2. In 1961, the Henry Mountain bison herd in Utah was declared free of brucellosis after a 2-year disease eradication campaign that utilized test and removal. This herd originated from Yellow- stone National Park bison in 1941, and had a peak seroprevalence rate of approximately 10% in 1961 (Nishi, 2010). Recent research has shown that the Henry Mountain bison herd represents a genetically important subpopulation of the YNP-based metapopulation. This herd meets the YNP standard of no detectable cattle introgression, but is also free of brucellosis (Ranglack et al., 2015). 3. In 1973, the Custer State Park bison herd in South Dakota was declared free of brucellosis after a 10-year disease management program from 1963 to 1973. That herd had a peak seropositive rate of 48% in 1961. A combination of annual vaccination of calves and yearlings, test and removal, and herd size reduction were utilized (Nishi, 2010). 4. In 1974, the Wichita Mountain National Wildlife Refuge bison herd in Oklahoma went from 3% seropositive to free of brucellosis after an 11-year disease management effort. A combination of test and removal, population reduction, isolation of select groups, and vaccination of calves up until 1973 were utilized to free the herd of brucellosis (Nishi, 2010). 5. In 1985, the Wind Cave National Park bison herd in South Dakota went from a high seroposi- tive rate of 85% in 1945 to brucellosis free after a disease management effort conducted from 1964 to 1985. A combination of whole herd and calfhood vaccination and test and removal were utilized (Nishi, 2010). 6. In 2000, a privately owned bison herd in South Dakota was released from quarantine after a 10-year effort to eliminate brucellosis from the herd. This was accomplished by a combination of testing and removal of positive animals, and herd management to reduce exposure and trans- mission. The main herd of older, chronically infected animals was depopulated in January 1999. Prepublication Copy—Subject to Further Editorial Revision 119

Revisiting Brucellosis in the Greater Yellowstone Area Younger, uninfected animals from calf crops were separated, intensely vaccinated with RB51, tested, and retained on the ranch to rebuild the herd (USAHA, 2000). None of the cases above, however, are comparable to the bison herds in the GYA, and those situa- tions did not involve affected elk populations. Data are limited on the use of test and removal alone or in combination with other methods. Hobbs and colleagues (2015) forecasted the effects of annually remov- ing 200 seropositive bison using a Bayesian model that included uncertainties associated with a number of important parameters. Removal of seropositive bison was one of the few management actions likely to reduce seroprevalence in the short term: from 55% to 14% over 5 years, although the credibility interval was still large, ranging from 0.12% to 57% in the fifth year (Hobbs et al., 2015). In elk, the Muddy Creek pilot project was conducted from 2006-2011 to assess the use of test and remove to reduce prevalence of brucellosis in elk attending a Wyoming feedground. Data from that study showed that capturing nearly half of available yearling and adult female elk attending a feedground, test- ing for B. abortus, and removing those that test positive can reduce antibody prevalence of brucellosis in captured elk by more than 30% in 5 years. However, once the pilot project ended, the seroprevalence of brucellosis in elk on the feedgrounds resurged (Scurlock et al., 2010). A variant of testing with the intention of lethal removal is test and quarantine. A bison quarantine pi- lot project was initiated in 2005 to determine whether it was feasible to qualify animals originating from the YNP bison herd as free from brucellosis. This project used the concept of separating seronegative, young animals so as to minimize exposure, with testing and removal. A majority of those animals were subsequently declared brucellosis-free and were moved to other locations, including to two Native Amer- ican rangelands. 9. VACCINES AND DELIVERY SYSTEMS FOR CATTLE, BISON, AND ELK Vaccination is proven to prevent or mitigate infectious diseases. A number of highly efficacious commercial vaccines exist against bacterial diseases for use in cattle, including against Leptospira borgpetersenei serovar Hardjo-bovis, as well as vaccines for human such as those against bacterial men- ingitis, tetanus, and Haemophilus influenza B. Vaccines have been shown to be an effective tool to con- trol the spread of brucellosis when combined with management practices. Adult cattle can be safely vac- cinated with conventional Brucella vaccines via a primary or boosting dose, and cattle may be pregnant when vaccinated. This has been shown to be efficacious and to increase the immune response as meas- ured using in vitro tests. In wildlife, development of oral vaccination strategies would be preferable to ballistic or needle injection, and a limited number of studies have shown promise. 9.1 Improving Cattle Vaccines Cattle vaccines to date have been designed to protect against B. abortus-induced abortion and not against infection. Many of the brucellosis concerns in cattle could potentially be resolved by improving cattle vaccines for resistance to infection even under high dosage challenge conditions and even when herd immunity is compromised by co-mingling with infected wildlife (bison and elk). In the long run, an effective vaccine to protect against infection could reduce the legal, political, and financial costs associat- ed with brucellosis in cattle. Improvements would be needed for adult vaccines (for both primary immun- izations and booster doses for previously vaccinated cattle) and therapeutic vaccines that boost or retrain immune responses of animals already infected with Brucella (Wright, 1942). If it were possible to devel- op a vaccine that would not only prevent abortion but also prevent infection in cattle, the need for wildlife vaccines may be less paramount. Comprehensive delivery of vaccines may be a particular challenge that could be avoided if cattle vaccines were sufficiently improved. 120 Prepublication Copy—Subject to Further Editorial Revision

Management Options 9.2 Delivery Systems for Brucellosis Vaccination of Wildlife Vaccinating wildlife can be challenging. Vaccines have been delivered to elk by needle immuniza- tion and biobullets, but have been ineffective. Elk are widely dispersed and mobile, and many herds— including some that are infected at a high rate—do not concentrate on accessible feedgrounds in the win- ter. Even if an efficacious vaccine were available for elk, vaccinating elk populations in the GYA is infea- sible in the absence of a novel method for delivering the vaccine (beyond biobullets or darting). Progress toward a feasible delivery system along with developing efficacious vaccines for elk will both be critical. A recent modification of Komarov’s bullets has been made and was shown to induce both antibody and cellular responses in cattle and bison with no detrimental effects (Denisov et al., 2010). While it can be delivered from 100 meters, the safety range is 40-60 meters which may not be feasible for all terrains found in the GYA (Denisov et al., 2010). Oral vaccines have been suggested to better stimulate mucosal immunity, because exposure to bru- cellosis is generally through the mucosa. The gut mucosa regularly samples antigens from in the intestinal lumen via dendritic cells embedded within the epithelium or via specialized microfold cells. Brucella an- tigens are then picked up and delivered to the mucosal and systemic immune systems to stimulate anti- vaccine immunity. Thus oral vaccines may be more effective at preventing infection than parenteral administration of the vaccine. The administration of B. abortus strain 19 (S19) vaccine by oral vaccina- tion proved to be equally as effective as subcutaneous vaccination in protecting pregnant heifers from Brucella-induced abortion (Nicoletti and Milward, 1983; Nicoletti, 1984). Cattle have been immunized orally with B. abortus strain RB51 (RB51) as a model for wildlife. When RB51 was mixed with feed and fed to beef heifers which were then bred and exposed to a challenge dose of 107 B. abortus strain 2308 organisms, it was shown that there was protection from abortion in 70% of the vaccinates but only 30% of the unvaccinated controls (Elzer et al., 1998). Microspheres composed of eggshell-precursor protein of Fasciola hepatica (Vitelline protein B) have been used to orally vaccinate red deer (Cervus elaphus elaphus) with RB51. This was shown to induce a good cellular immune response, as measured by lym- phocyte proliferation assays, as well as induce an antibody response (IgG) (Arenas-Gamboa et al., 2009b). Following challenge with another vaccine strain (S19), there was reduced bacteria in the spleens of vaccinates. A similar study using alginate microencapsuled S19 organisms to immunize red deer also showed a cellular immune response (Arenas-Gamboa et al., 2009a). Less considered is uptake of brucel- lae in the tonsils following exposures of the head and neck mucosa (Suraud et al., 2008). Vaccination of the tonsils may improve protection against Brucella infections. Thus the development of oral and mucosal vaccination strategies for wildlife are promising. 10. STERILIZATION AND CONTRACEPTIVES The use of sterilization and contraceptives as a tool for wildlife management is controversial. Although it cannot prevent infection, sterilizing bison or elk early in life could prevent them from breed- ing, becoming pregnant, and if they are also infected with brucellosis, aborting and exposing cattle or oth- er wildlife. Surgical sterilization of cattle (spaying heifers) has been a procedure used by stockmen for years to reduce or prevent transmission of brucellosis in cattle herds. Surgically spaying wild elk and bi- son is infeasible, but non-surgical reproductive control via contraception may be feasible. Contraception of bison as a potential means to slow brucellosis transmission in wildlife may be more effective than test- ing and removal (Ebinger et al., 2011). Ebinger and colleagues posit that in social species that form groups, sterilized individuals essentially create herd immunity similar to effective vaccination efforts. On the other hand, when seropositive individuals are removed from the population, the social group may re- form and bring susceptible individuals into greater contact with the remaining infectious individuals, thereby reducing herd immunity and increasing the potential for a strong resurgence of disease (Ebinger et al., 2011). USDA-APHIS has recently conducted research on the possible use of a gonadotropin releasing hor- mone (GnRH) antagonist vaccine (GonaCon™) as a method of inducing sterility in bison and elk (Rhyan, Prepublication Copy—Subject to Further Editorial Revision 121

Revisiting Brucellosis in the Greater Yellowstone Area 2015). Earlier efforts using a zona pellucida vaccine were deemed ineffective (Kirkpatrick et al., 2011). Experimental trials with GonaCon™ in elk were underway as of the writing of this report. Information provided by USDA indicated that GonaCon™ has been approved by EPA for use in deer and wild horses (Rhyan, 2015). In most species, GonaCon™ provided 2-3 years of sterility and the animals were anestrus (did not come into breeding condition). However, 5-15% of animals became permanently sterile (up to 5 years), adjuvants caused some injection site reactions (abscesses), and protection was not 100% (Rhyan, 2015). GonaCon™ has been better tested in bison than elk. From 2002-2008, five vaccinated captive bison in Idaho did not calve while a small number of control bison calved 75% of the time (Rhyan, 2015). Bi- son that were in mid to late pregnancy when first vaccinated calved normally. A dose-response study showed that a high dose of GonaCon™ was 86% effective, low dose was 50% effective, and the medium dose between those levels (Rhyan, 2015). In field trials with free-ranging bison in southern Colorado, there were mixed results: GonaCon™ vaccinated cows had 7 calves while unvaccinated cows had 24 calves. A field trial at Corwin Springs examined rates of infection and abortion in 20 vaccinated and 20 control bison cows exposed to brucellosis, and GonaCon™ appeared to be effective at significantly re- ducing abortion and birthing of infected bison calves (Rhyan, 2015). Another set of trials at Corwin Springs with 15 vaccinates and 15 controls had mixed results. In the first year, 75% of controls became pregnant while 20% of vaccinates did; in the second year, 77% of controls became pregnant while only 13% of vaccinates did; in the third year, 90% of controls became pregnant but so did 36% of vaccinates (Rhyan, 2015). No large, free-ranging wildlife population in North America has ever been successfully managed us- ing contraception. Modeling studies for wild horses suggests that even highly effective contraceptives can at best only slow population growth (Garrott et al., 1992; Gross, 2000; Ballou et al., 2008). Contraception conjures up the notion of manipulation that may unacceptable to the public. By decreasing reproduction, it could also be seen as decreasing future hunter harvest and potentially jeopardizing their acceptance. The management of elk inside national parks is under the jurisdiction of the National Park Service and outside national parks is under the authority of state wildlife management agencies. It is unclear whether state agencies or the National Park Service would allow experimental use of GnRH vaccines in free-ranging elk as part of brucellosis management efforts. With limited information available on GonaCon and other contraceptive approaches at the writing of this report, they would currently not be considered as a viable management option. 11. PREDATION AND SCAVENGERS There are a number of mechanisms by which both scavengers and predators are likely to affect the distribution and abundance of elk as well as the transmission and prevalence of brucellosis. Scavengers and predators play a valuable role in suppressing the spread of brucellosis, as B. abortus is known to sur- vive for weeks or months under typical GYA winter conditions, and up to 6 months if protected from sun- light (Stableforth, 1959). For the most part, the efficacy of predation and scavenging to alter brucellosis dynamics is unknown and untested. In the absence of healthy predator populations, however, elk may ex- ceed management objectives, particularly in regions with limited hunter access (Haggerty and Travis, 2006; Cole et al., 2015). In this scenario, managers could consider further restricting the tag limits on predators or increasing the tag limits for elk. This would likely be a contentious decision, and it remains to be determined whether the benefits associated with fewer elk would be offset by the additional live- stock losses that are likely to coincide with increasing predator populations in localized areas. USDA-APHIS’s Wildlife Services removes coyotes from many regions across the country at the request of individual landowners. Coyotes are categorized as predators and can be shot or trapped in Ida- ho, Montana, and Wyoming without a license. However, coyotes are a major scavenger of aborted fetus- es, and they are likely to reduce transmission rates both among elk and between elk and livestock (Maichak et al., 2009). Coyote hunting is unregulated, thus it is unknown how many coyotes are removed annually and whether restricting coyote harvest would have any beneficial effect on brucellosis transmis- 122 Prepublication Copy—Subject to Further Editorial Revision

Management Options sion. Again, this management tool is likely to incur a direct trade-off for the producer in the form of addi- tional calf losses. Several different avenues could be explored with respect to trained dogs (Wasser et al., 2004). First, in localized areas such as winter feedlines, dogs could be used by producers to investigate an area for fe- tuses daily prior to bringing cattle out. Because this would create a significant risk to the dog for becom- ing infected with brucellosis, the dogs would need to be muzzled to prevent ingestion or trained to find abortions in an area and to stay a safe distance away. In addition, dogs have been used in some cases to detect certain forms of cancer in humans (Cornu et al., 2011). If detection dogs could be used pen-side to detect actively infected elk, bison, or cattle, this would facilitate more targeted test-and-remove or sterili- zation approaches. REFERENCES Adams, G.L. 1990. Advances in Brucellosis Research. College Station, TX: Texas A&M University Press. Almberg, E.S., P.C. Cross, C.J. Johnson, D.M. Heisey, and B.J. Richards. 2011. Modeling routes of chronic wasting disease transmission: Environmental prion persistence promotes deer population decline and extinction. PLoS ONE 6(5):e19896. Arenas-Gamboa, A.M., T.A. Ficht, D.S. Davis, P.H. Elzer, M. Kahl-McDonagh, A. Wong-Gonzalez, and A.C. Rice- Ficht. 2009a. Oral vaccination with microencapsuled strain 19 vaccine confers enhanced protection against Brucella abortus strain 2308 challenge in red deer (Cervus elaphus elaphus). Journal of Wildlife Diseases 45(4):1021-1029. Arenas-Gamboa, A.M., T.A. Ficht, D.S. Davis, P.H. Elzer, A. Wong-Gonzalez, and A.C. Rice-Ficht. 2009b. Enhanced immune response of red deer (Cervus elaphus) to live rb51 vaccine strain using composite microspheres. Journal of Wildlife Diseases 45(1):165-173. Ballou, J.D., K. Traylor-Holzer, A.A. Turner, A.F. Malo, D. Powell, J. Maldonado, and L. Eggert. 2008. Simulation model for contraceptive management of the Assateague Island feral horse population using individual-based data. Wildlife Research 35:502-512. Brandt, A., M. W. Sanderson, B.D. DeGroot, D.U. Thomson, and L.C. Hollis. 2008. Biocontainment, biosecurity and security practices in beef feedyards. Journal of American Veterinary Medical Association 232:262-269. Brennan, A. 2015. Landscape-scale Analysis of Livestock Brucellosis. USDA, Animal and Plant Health Inspection Service. Caetano, M.C., F. Afonso, R. Ribeiro, A.P. Fonseca, D.A. Abernethy, and F. Noinas. 2016. Control of bovine brucellosis from persitantly infected holdings using RB51 vaccination with test and slaughter: A comparative case report from a high incidence area in Portugal. Transboundary and Emerging Diseases 63:e39-e47. Clifford, D.L., B.A. Schumaker, T.R. Stephenson, V.C. Bleich, M.L. Cahn, B.J. Gonzales, W.M. Boyce, and J.A.K. Mazet. 2009. Assessing disease risk at the wildlife-livestock interface: A study of Sierra Nevada bighorn sheep. Biological Conservation 142:2558-2568. Coburn, D.R. 1948. Special Report of field Assignment at Yellowstone National Park, January 10-29, 1948. Yellowstone National Park, WY. 30 pp. Cole, E.K., A.M. Foley, J.M. Warren, B.L. Smith, S.R. Dewey, D.G. Brimeyer, W.S. Fairbanks, H. Sawyer, and P.C. Cross. 2015. Changing migratory patterns in the Jackson elk herd. Journal of Wildlife Management 79(6):877-886. Conner, M.M., M.W. Miller, M.R. Ebinger, and K.P. Burnham. 2007. A meta-BACI approach for evaluating man- agement intervention on chronic wasting disease in mule deer. Ecological Applications 17(1):140-153. Conover, M.R. 2001. Effects of hunting and traping on wildlife damage. Wildlife Society Bulletin 29(2):521-532. Consolo-Murphy, S. 2015. Presentation at the Second Committee Meeting on Revisiting Brucellosis in the Greater Yellowstone Area, September 15, 2015, Moran, MT. Cornu, J.-N., G. Cancel-Tassin, V. Ondet, C. Girardet, and O. Cussenot. 2011. Olfactory detection of prostate cancer by dogs sniffing urine: A step forward in early diagnosis. European Urology 59(2):197-201. Creech, T., P.C. Cross, B.M. Scurlock, E.J. Maichak, J.D. Rogerson, J.C. Henningsen, and S. Creel. 2012. Effects of low-density feeding on elk-fetus contact rates on Wyoming feedgrounds. Journal of Wildlife Management 76(5):877-886. Cross, P.C., W.H. Edwards, B.M. Scurlock, E.J. Maichak, and J.D. Rogerson. 2007. Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem. Ecological Applications 17(4):957-964. Prepublication Copy—Subject to Further Editorial Revision 123

Revisiting Brucellosis in the Greater Yellowstone Area Cross, P.C., E.K. Cole, A.P. Dobson, W.H. Edwards, K.L. Hamlin, G.Luikart, A.D. Middleton, B.M. Scurlock, and P.J. White. 2010a. Probable causes of increasing brucellosis in free-ranging elk of the Greater Yellowstone Ecosystem. Ecological Applications 20(1):278-288. Cross, P.C., D.M. Heisey, B.M. Scurlock, W.H. Edwards, M.R. Ebinger, and A. Brennan. 2010b. Mapping brucellosis increases relative to elk density using hierarchical Bayesian models. PLoS ONE 5(4):e10322. Denisov, A.A., O.M. Karpova, Y.S. Korobovtseva, K.M. Salmakov, O.D. Sklyarov, A.I. Klimanov, M.N. Brynskykh, K.V. Shumilov, and R.V. Borovick. 2010. Development and characterization of a modified Komarov’s bullet for ballistic delivery of live Brucella abortus strains 82 and 19 to cattle and bison. Vaccine 28(Suppl. 5):F23-F30. Ebinger, M.R., P.C. Cross, R.L. Wallen, P.J. White, and J. Treanor. 2011. Simulating sterilization , vaccination , and test-and-remove as brucellosis control measures in bison. Ecological Applications 21(8):2944-2959. Elzer, P.H., F.M. Enright, L. Colby, S.D. Hagius, J.V. Walker, M.B. Fatemi, J.D. Kopec, V. C. Beal, Jr., and G.G. Schurig. 1998. Protection against infection and abortion induced by virulent challenge exposure after oral vaccination of cattle with Brucella abortus strain RB51. American Journal of Veterinary Research 59(12):1575-1578. European Commission. 2009. P. 8 in Working Document on Eradication of Bovine, Sheep and Goats Brucellosis in the EU. Available online at http://ec.europa.eu/food/animals/docs/diseases_erad_bovine_sheep_goats_ brucellosis_en.pdf (accessed October 21, 2016). FAO (Food and Agriculture Organization of the United Nations). 2010. Good Practices for Biosecurity in the Pig Sector. Available online at http://www.fao.org/3/a-i1435e.pdf (accessed January 10, 2017). Foley, A.M., P.C. Cross, D.A. Christianson, B.M. Scurlock, and S. Creel. 2015. Influences of supplemental feeding on winter elk calf:cow ratios in the southern Greater Yellowstone Ecosystem. Journal of Wildlife Management 79(6):887-897. Forristal, V.E., S. Creel, M.L. Taper, B.M. Scurlock, and P.C. Cross. 2012. Effects of supplemental feeding and aggregation on fecal glucocorticoid metabolite concentrations in elk. Journal of Wildlife Management 76(4):694-702. Garrott, R.A., D.B. Siniff, J.R. Tester, T.C. Eagle, and E.D. Plotka. 1992. A comparison of contraceptive technolo- gies for feral horse management. Wildlife Society Bulletin 20:318-326. Goodwin, B.K., and T.C. Schroeder. 1994. Human capital, producer education programs, and the adoption of for- ward-pricing methods. American Journal of Agricultural Economics 76(4):936-947. Goodwin, B.K. and V.H. Smith. 2013. What harm is done by subsidizing crop insurance? American Journal of Ag- ricultural Economics 95(2):489-497. Grannis, J.L., J.W. Green, and M.L. Bruch. 2004. Animal health: The potential role for livestock disease insurance. Western Economics Forum, April 2004. Available online at http://ageconsearch.umn.edu/bitstream/ 27972/1/03010001.pdf (accessed January 10, 2017). Gross, J.E. 2000. A dynamic simulation model for evaluating effects of removal and contraception on genetic varia- tion and demography of Pryor Mountain wild horses. Biological Conservation 96:319-330. Haggerty, J.H., and W.R. Travis. 2006. Out of administrative control: Absentee owners, resident elk and the shifting nature of wildlife management in southwestern Montana. Geoforum 37:816-830. Heffelfinger, J.R. 2013. Hunting and trapping. Pp. 130-143 Wildlife Management and Conservation: Contemporary Principles & Practices, P. Krausman, and J. Caine, eds. Baltimore: Johns Hopkins University Press. Hoag, D.L., D.D. Thilmany, and S.R. Koontz. 2006. Economics of livestock disease insurance—Principles, issues and worldwide cases. Pp. 1-18 in The Economics of Livestock Disease Insurance: Concepts, Issues and Inter- national Case Studies, S.R. Koontz, D.L. Hoag, D.D. Thilmany, J.W. Green, and J.l. Grannis, eds. Walling- ford, UK: CABI. Jennelle, C.S., V. Henaux, G. Wasserberg, B. Thiagarajan, R. Rolley, and M.D. Samuel. 2014. Transmission of chronic wasting disease in Wisconsin white-tailed deer: Implications for disease spread and management. PLoS ONE 9(3):e91043. Kamath, P., J. Foster, K. Drees, C. Quance, G. Luikart, N. Anderson, P. Clarke, E. Cole, W. Edwards, J. Rhyan, J. Treanor, R. Wallen, S. Robbe-Austerman, and P. Cross. 2016. Whole genome sequencing reveals brucellosis transmission dynamics among wildlife and livestock of the Greater Yellowstone ecosystem. Nature Commu- nications 7:11448. Kirkpatrick, L.F., R.O. Lyda, and K.M. Frank. 2011. Contraceptive vaccines for wildlife: A review. American Jour- nal of Reproductive Immunology 66:40-50. 124 Prepublication Copy—Subject to Further Editorial Revision

Management Options Krausman, P.R. 2013. Defining wildlife and wildlife management. Pp. 1-5 in Wildlife Management and Conserva- tion: Contemporary Principles & Practices, P. Krausman, and J. Caine, eds. Baltimore: Johns Hopkins Univer- sity Press. Lloyd-Smith, J.O., P.C. Cross, C.J. Briggs, M. Daugherty, W.M. Getz, J. Latto, M.S. Sanchez, A.B. Smith, and A. Swei. 2005. Should we expect population thresholds for wildlife disease? Trends in Ecology & Evolution 20(9):511-519. Lundquist, L. 2014. Yellowstone National Park rejects remote brucellosis vaccination. Bozeman daily Chronicle, January 14, 2014. Available online at http://www.bozemandailychronicle.com/news/wildlife/yellow stone-national-park-rejects-remote-brucellosis-vaccination/article_33ba0406-7d7d-11e3-84bf-001a4bcf887a a.html (accessed January 10, 2017). Maichak, E.J., B.M. Scurlock, J.D. Rogerson, L.L. Meadows, A.E. Barbknecht, W.H. Edwards, and P.C. Cross. 2009. Effects of management, behavior, and scavenging on risk of brucellosis transmission in elk of western Wyoming. Journal of Wildlife Diseases 45(2):398-410. Mathiason, C.K., J.G. Powers, S.J. Dahmes, D.A. Osborn, K.V. Miller, R.J. Warren, G.L. Mason, S.A. Hays, J. Hayes-Klug, D.M. Seelig, M.A. Wild, L.L. Wolfe, T.R. Spraker, M.W. Miller, C.J. Sigurdson, G.C. Telling, and E.A. Hoover. 2006. Infectious prions in the saliva and blood of deer with chronic wasting disease. Science 314(5796):133-136. McCullough, D.R. 1979. The Georges Reserve Deer Herd: Population Ecology of a K-selected Species. Ann Arbor, MI: University of Michigan Press. MDFWP (Montana Department of Fish, Wildlife, and Parks). 2015. Presentation at the First Committee Meeting on Revisiting Brucellosis in the Greater Yellowstone Area, July 1, 2015, Bozeman, MT. Miller, M.W., E.S. Williams, N.T. Hobbs, and L.L. Wolfe. 2004. Environmental sources of prion transmission in mule deer. Emerging Infectious Diseases 10(6):1003-1006. Nicoletti, P. 1984. Vaccination of cattle with Brucella abortus strain 19 administered by differing routes and doses. Vaccine 2:133-135. Nicoletti, P., and F.W. Milward. 1983. Protection by oral administration of Brucella abortus strain 19 against an oral challenge exposure with a pathogenic strain of Brucella. American Journal of Veterinary Research 44:1641- 1643. Nielsen, K., and J.R. Duncan. 1990. Animal Brucellosis. Boca Raton, FL: CRC Press. Nishi, J.S. 2010. A Review of Best Practices and Principles for Bison Disease Issues : Greater Yellowstone and Wood Buffalo Areas. ABS Working Paper No. 3. Bronx, NJ:American Bison Society and Wildlife Conservation Society. NRC (National Research Council). 1998. Brucellosis in the Greater Yellowstone Area. Washington, DC: National Academy Press. 186 pp. Organ, J.F. 2013. The wildlife professional. Pp. 24-33 in Wildlife Management and Conservation: Contemporary Principles & Practices, P. Krausman, and J. Caine, eds. Baltimore: Johns Hpkins University Press. PAHO (Pan American Health Organization). 2001. Zoonoses and Communicable Diseases Common To Man and Animals. Scientific and Technical Publication No. 580. Available online at http://www.paho.org/hq/index. php?option=com_docman&task=doc_view&gid=19187&Itemid=270 (accessed January 10, 2017). Peck, D.E. 2010. Bovine brucellosis in the Greater Yellowstone area: An economic diagnosis. Western Economic Forum, Spring 2010. Available online at http://ageconsearch.umn.edu/bitstream/176167/2/WEF-Vol.9-No.1- Spring2010-1_Peck.pdf (accessed January 10, 2017). Pennings, J.M.E., and P. Garcia. 2001. Measuring producers’ risk preferences: A global risk-attitude construct. American Journal of Agricultural Economics 83(4):993-1009. Pérez-Sancho, M., T. García-Seco, L. Domínguez, and J. Álvarez. 2015. Control of animal brucellosis — The most effective tool to prevent human brucellosis. Pp. 201-246 in Updates on Brucellosis, M.M. Baddour, ed. InTech. Available online at http://cdn.intechopen.com/pdfs-wm/49083.pdf (accessed January 10, 2017). Proffitt, K.M., N. Anderson, P. Lukacs, M.M. Riordan, J.A. Gude, and J. Shamhart. 2015. Effects of elk density on elk aggregation patterns and exposure to brucellosis. Journal of Wildlife Management 79(3):373-383. Ranglack, D.H., L.K. Dobson, J.T. du Toit, and J. Derr. 2015. Genetic analysis of the Henry Mountains Bison Herd. PLoS One 10(12):e0144239. Reeling, C.J., and R.D. Horan. 2014. Self-protection, strategic interactions, and relative endogeneity of disease risks. American Journal of Agricultural Economics 97(2):452-468. Rhyan, J. 2015. USDA APHIS Brucellosis Research Efforts. Presentation at the Third Committee Meeting on Revis- iting Brucellosis in the Greater Yellowstone Area, September 15, 2015, Jackson Lake Lodge, WY. Prepublication Copy—Subject to Further Editorial Revision 125

Revisiting Brucellosis in the Greater Yellowstone Area Rice, E. 2015. Impact of Brucellosis on Montana Livestock Production. Presentation at the First Committee Meeting on Revisiting Brucellosis in the Greater Yellowstone Area, July 2, 2015, Bozeman, MT. Rimbey, N., and L.A. Toreel. 2011. Grazing Costs: What’s the Current Situation? Agricultural Economics Extension Series No 2011-02, March 22, 2011. Moscow, ID: University of Idaho. Available online at http://web.cals. uidaho.edu/idahoagbiz/files/2013/01/GrazingCost2011.pdf (accessed May 26, 2017). Roberts, T.W., D.E. Peck, and J.P. Ritten. 2012. Cattle producers’ economic incentives for preventing bovine bru- cellosis under uncertainty. Preventive Veterinary Medicine 3:187-203. Schurig, G. 2015. Presentation at the Third Committee Meeting on Revisiting Brucellosis in the Greater Yellow- stone Area, November 10, 2015, Washington, DC. Schurig, G.G., R.M. Roop II, T. Bagchi, S. Boyle, D. Buhrman, and N. Sriranganathan. 1991. Biological properties of RB51; a stable rough strain of Brucella abortus. Veterinary Microbiology 28:171-188. Scurlock, B.M., W.H. Edwards, T. Cornish, and L. Meadows. 2010. Using Test and Slaughter To Reduce Prevalence of Brucellosis in Elk Attending Feedgrounds in the Pinedale Elk Herd Unit of Wyoming; Results of a 5 Year Pilot Program. Available online at https://wgfd.wyo.gov/WGFD/media/content/PDF/Wildlife/ TR_REPORT_2010_FINAL.pdf (accessed January 10, 2017). Smith, B.L. 2001. Winter feeding of elk in western North America. Journal of Wildlife Management 65(2):173-190. Smith, B.L. 2013. Winter elk feeding = disease facilitation. Wildlife Professional Winter 2013:42-47. Smith, B.L., and S.H. Anderson. 1998. Juvenile survival and population regulation of the Jackson Elk Herd. Journal of Wildlife Management 62(3):1036-1045. Sorensen, A., F.M. van Beest, and R.K. Brook. 2014. Impacts of wildlife baiting and supplemental feeding on infec- tious disease transmission risk: A synthesis of knowledge. Preventive Veterinary Medicine 113(4):356-363. Stableforth, A.W. 1959. Brucellosis. Pp. 53-159 in Infectious Disease of Wild Animals, Vol 1. Diseases Due to Bac- teria, A.W. Stableforth, and I.A. Galloway, eds. New York: Academic Press. Suraud, V., I. Jacques, M. Olivier, and L.A. Guilloteau. 2008. Acute infection by conjunctival route with Brucella melitensis induces IgG+ cells and IFN-gamma producing cells in peripheral and mucosal lymph nodes in sheep. Microbes and Infection 10:1370-1378. USAHA (U.S. Animal Health Association). 2000. Report of the Committee on Brucellosis. Pp. 191-192 in U.S. Animal Health Association Proceedings from the104th Annual Meeting October 19-26, 2000, Birmingham, AL. Richmond, VA: Pat Campbell and Associates. USDA-APHIS (U.S. Department of Agriculture Animal and Plant Health Inspection Service). 2009. A Concept Pa- per for a New Direction for the Bovine Brucellosis Program. Available online at https://www.avma. org/Advocacy/National/Federal/Documents/0912_concept_paper_for_bovine_br_program_aphis-2009-0006-0 002.pdf (accessed June 4, 2016). USDA-APHIS. 2012. APHIS Reviews of Greater Yellowstone Area State DSAs. USDA APHIS. 2016. Conditions for Payment of Highly Pathogenic Avian Influenza Indemnity Claims, February 6, 2016. Available online at http://www.regulations.gov/#!documentDetail;D=APHIS-2015-0061-0001. USDA-NASS (U.S. Department of Agriculture National Agricultural Statistics Service). 2010. Agricultural Statis- tics. Available online at https://www.nass.usda.gov/Publications/Ag_Statistics/2010/2010.pdf (accessed May 26, 2017). USFWS (U.S. Fish and Wildlife Service). 2012. National Survey of Fishing, Hunting, and Wildlife-Associated Rec- reation. U.S. Department of the Interior, U.S. Fish and Wildlife Service, and U.S. Department of Commerce, U.S. Census Bureau. Available online at http://www.census.gov/prod/2012pubs/fhw11-nat.pdf (accessed Jan- uary 10, 2017). Wasser, S.K., B. Davenport, E.R. Ramage, K.E. Hunt, M. Parker, C. Clarke, and G. Stenhouse. 2004. Scat detection dogs in wildlife research and management: Application to grizzly and black bears in the Yellowhead Ecosys- tem, Alberta, Canada. Canadian Journal of Zoology 82(3):475-492. Wasserberg, G., E.E. Osnas, R.E. Rolley, and M.D. Samuel. 2009. Host culling as an adaptive management tool for chronic wasting disease in white-tailed deer: A modelling study. Journal of Applied Ecology 46(2):457-466. WGFD (Wyoming Game and Fish Department). 2008a. Jackson Bison Herd Brucellosis Management Action Plan. Available online at https://wgfd.wyo.gov/Wildlife-in-Wyoming/More-Wildlife/Wildlife-Disease/Brucellosis/ Brucellosis-Reports (accessed January 11, 2017). WGFD. 2008b. Brucellosis Management Action Plan for Bison Using the Absaroka Management Area. Available online at https://wgfd.wyo.gov/Wildlife-in-Wyoming/More-Wildlife/Wildlife- Disease/Brucellosis/Brucellosis- Reports (accessed January 11, 2017). WGFD. 2010. Annual Report. Available online at https://wgfd.wyo.gov/WGFD/media/content/PDF/About%20Us/ Commission/WGFD_ANNUALREPORT_2010.pdf (accessed January 10, 2017). 126 Prepublication Copy—Subject to Further Editorial Revision

Management Options WGFD. 2011. Jackson Elk Herd Unit Brucellosis Management Action Plan Update. Available online at https://wgfd.wyo.gov/Wildlife-in-Wyoming/More-Wildlife/Wildlife-Disease/Brucellosis/Brucellosis-Reports (accessed January 10, 2017). WGFD. 2012. Cody Elk Herd Unit Brucellosis Management Action Plan. Available online at https://wgfd.wyo.gov/ Wildlife-in-Wyoming/More-Wildlife/Wildlife-Disease/Brucellosis/Brucellosis-Reports (accessed January 10, 2017). WGFD. 2015. Presentation at the Second Committee Meeting on Revisiting Brucellosis in the Greater Yellowstone Area, September 15, 2015, Moran, WY. Williams, E.S. 2005. Chronic wasting disease. Veterinary Pathology 42(5):530-549. Williams, E.S., and S. Young. 1980. Chronic wasting disease of captive mule deer—spongiform encephalopathy. Journal of Wildlife Diseases 16(1):89-98. Wolf, C., and N. Widmar, 2014 Adoption of milk and feed forward pricing methods by dairy farmers. Journal of Agricultural and Applied Economics 46(4):527-541. Wright, A.E. 1942. Report of the co-operative bovine brucellosis work in the United States. Proceedings of the U.S. Livestock Sanitary Association 47:149-154. Prepublication Copy—Subject to Further Editorial Revision 127

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Revisiting Brucellosis in the Greater Yellowstone Area Get This Book
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Brucellosis is a nationally and internationally regulated disease of livestock with significant consequences for animal health, public health, and international trade. In cattle, the primary cause of brucellosis is Brucella abortus, a zoonotic bacterial pathogen that also affects wildlife, including bison and elk. As a result of the Brucellosis Eradication Program that began in 1934, most of the country is now free of bovine brucellosis. The Greater Yellowstone Area (GYA), where brucellosis is endemic in bison and elk, is the last known B. abortus reservoir in the United States. The GYA is home to more than 5,500 bison that are the genetic descendants of the original free-ranging bison herds that survived in the early 1900s, and home to more than 125,000 elk whose habitats are managed through interagency efforts, including the National Elk Refuge and 22 supplemental winter feedgrounds maintained in Wyoming.

In 1998 the National Research Council (NRC) issued a report, Brucellosis in the Greater Yellowstone Area, that reviewed the scientific knowledge regarding B. abortus transmission among wildlife—particularly bison and elk—and cattle in the GYA. Since the release of the 1998 report, brucellosis has re-emerged in domestic cattle and bison herds in that area. Given the scientific and technological advances in two decades since that first report, Revisiting Brucellosis in the Greater Yellowstone Area explores the factors associated with the increased transmission of brucellosis from wildlife to livestock, the recent apparent expansion of brucellosis in non-feedground elk, and the desire to have science inform the course of any future actions in addressing brucellosis in the GYA.

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