Brucellosis is a nationally and internationally regulated disease of livestock with significant consequences for animal health, public health, and international trade. NOROCK provides science based on an interdisciplinary approach to several key aspects: 1) estimating and modeling disease dynamics within and among wildlife species and populations, 2) identifying risks to cattle, and 3) assessing the effectiveness of different management interventions.
Background
In countries with less resources, brucellosis in humans is a serious recurring illness, and is one of the most economically important zoonotic diseases (spread from animals to humans) globally.
- 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 Ecosystem (GYE), where brucellosis is constantly present in bison and elk, is the last known B. abortus reservoir in the U.S.
- The GYE is home to more than 5,500 bison that are the genetic descendants of the original free-ranging bison herds that survived into the early 1900s.
- GYE is also 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.
Risk to Cattle
Between April 2002 and November 2016, 22 beef cattle herds and 5 domestic bison herds were infected around the GYE.
- While this is a small number of domestic herds, the economic consequences of quarantine, depopulation, and/or test and removal of cattle can be high for cattle and bison owners.
- In addition, given the high rate of cattle movement around the U.S., the safety of the rest of the U.S. cattle population depends on the ability to detect and contain these cases of wildlife-livestock spillover.
Transmission from Wildlife
Except for the feedgrounds, elk were previously thought to be poor disease hosts.
- However, our research has shown that many elk populations have increased over the past 50 years
- here have been coincident increases in the number of elk testing positive for brucellosis in the GYE
- These results may have important implications for the management of brucellosis in the GYE, shifting some of the focus from bison to elk.
- Our research has determined that brucellosis around the GYE is related to elk moving away from the feedgrounds rather than spreading from bison to elk
- Suggests that gains in the control of brucellosis in the GYE are more likely to be achieved if focused on elk
Below are publications associated with this project.
Assessment of a strain 19 brucellosis vaccination program in elk Assessment of a strain 19 brucellosis vaccination program in elk
Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock
Managing more than the mean: Using quantile regression to identify factors related to large elk groups Managing more than the mean: Using quantile regression to identify factors related to large elk groups
Changing migratory patterns in the Jackson elk herd Changing migratory patterns in the Jackson elk herd
Estimating the phenology of elk brucellosis transmission with hierarchical models of cause-specific and baseline hazards Estimating the phenology of elk brucellosis transmission with hierarchical models of cause-specific and baseline hazards
Influences of supplemental feeding on winter elk calf:cow ratios in the southern Greater Yellowstone Ecosystem Influences of supplemental feeding on winter elk calf:cow ratios in the southern Greater Yellowstone Ecosystem
Sex-biased gene flow among elk in the greater Yellowstone ecosystem Sex-biased gene flow among elk in the greater Yellowstone ecosystem
Female elk contacts are neither frequency nor density dependent Female elk contacts are neither frequency nor density dependent
An ecological perspective on the changing face of Brucella abortus in the western United States An ecological perspective on the changing face of Brucella abortus in the western United States
Effects of low-density feeding on elk–fetus contact rates on Wyoming feedgrounds Effects of low-density feeding on elk–fetus contact rates on Wyoming feedgrounds
Probable causes of increasing brucellosis in free-ranging elk of the Greater Yellowstone Ecosystem Probable causes of increasing brucellosis in free-ranging elk of the Greater Yellowstone Ecosystem
Mapping brucellosis increases relative to elk density using hierarchical Bayesian models Mapping brucellosis increases relative to elk density using hierarchical Bayesian models
Below are partners associated with this project.
Brucellosis is a nationally and internationally regulated disease of livestock with significant consequences for animal health, public health, and international trade. NOROCK provides science based on an interdisciplinary approach to several key aspects: 1) estimating and modeling disease dynamics within and among wildlife species and populations, 2) identifying risks to cattle, and 3) assessing the effectiveness of different management interventions.
Background
In countries with less resources, brucellosis in humans is a serious recurring illness, and is one of the most economically important zoonotic diseases (spread from animals to humans) globally.
- 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 Ecosystem (GYE), where brucellosis is constantly present in bison and elk, is the last known B. abortus reservoir in the U.S.
- The GYE is home to more than 5,500 bison that are the genetic descendants of the original free-ranging bison herds that survived into the early 1900s.
- GYE is also 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.
Risk to Cattle
Between April 2002 and November 2016, 22 beef cattle herds and 5 domestic bison herds were infected around the GYE.
- While this is a small number of domestic herds, the economic consequences of quarantine, depopulation, and/or test and removal of cattle can be high for cattle and bison owners.
- In addition, given the high rate of cattle movement around the U.S., the safety of the rest of the U.S. cattle population depends on the ability to detect and contain these cases of wildlife-livestock spillover.
Transmission from Wildlife
Except for the feedgrounds, elk were previously thought to be poor disease hosts.
- However, our research has shown that many elk populations have increased over the past 50 years
- here have been coincident increases in the number of elk testing positive for brucellosis in the GYE
- These results may have important implications for the management of brucellosis in the GYE, shifting some of the focus from bison to elk.
- Our research has determined that brucellosis around the GYE is related to elk moving away from the feedgrounds rather than spreading from bison to elk
- Suggests that gains in the control of brucellosis in the GYE are more likely to be achieved if focused on elk
Below are publications associated with this project.
Assessment of a strain 19 brucellosis vaccination program in elk Assessment of a strain 19 brucellosis vaccination program in elk
Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock
Managing more than the mean: Using quantile regression to identify factors related to large elk groups Managing more than the mean: Using quantile regression to identify factors related to large elk groups
Changing migratory patterns in the Jackson elk herd Changing migratory patterns in the Jackson elk herd
Estimating the phenology of elk brucellosis transmission with hierarchical models of cause-specific and baseline hazards Estimating the phenology of elk brucellosis transmission with hierarchical models of cause-specific and baseline hazards
Influences of supplemental feeding on winter elk calf:cow ratios in the southern Greater Yellowstone Ecosystem Influences of supplemental feeding on winter elk calf:cow ratios in the southern Greater Yellowstone Ecosystem
Sex-biased gene flow among elk in the greater Yellowstone ecosystem Sex-biased gene flow among elk in the greater Yellowstone ecosystem
Female elk contacts are neither frequency nor density dependent Female elk contacts are neither frequency nor density dependent
An ecological perspective on the changing face of Brucella abortus in the western United States An ecological perspective on the changing face of Brucella abortus in the western United States
Effects of low-density feeding on elk–fetus contact rates on Wyoming feedgrounds Effects of low-density feeding on elk–fetus contact rates on Wyoming feedgrounds
Probable causes of increasing brucellosis in free-ranging elk of the Greater Yellowstone Ecosystem Probable causes of increasing brucellosis in free-ranging elk of the Greater Yellowstone Ecosystem
Mapping brucellosis increases relative to elk density using hierarchical Bayesian models Mapping brucellosis increases relative to elk density using hierarchical Bayesian models
Below are partners associated with this project.