Pneumonia in Bighorn Sheep Active
Bighorn sheep populations are often impacted by outbreaks of pneumonia that are suspected to come from domestic sheep and goats.
During the initial phases of these outbreaks large mortalities occur across all ages of bighorn sheep. During subsequent years, sporadic cases of pneumonia in adult bighorn sheep sometimes occur, but more importantly lambs continue to suffer disease, resulting in low recruitment and stagnant population growth. Pneumonia is one of the biggest hurdles limiting the comeback of bighorn sheep in western North America. A number of different pathogens are often detected during die-off events, which has made it difficult to determine if there is a causative agent that is behind most or all of the outbreaks. Recent evidence suggests that Mycoplasma ovipneumoniae (M. ovi.) is consistently associated with outbreaks and is often associated with a single strain in each outbreak suggesting a recent introduction.
One of our current projects is to genotype M. ovi. isolates from bighorn sheep, domestic sheep, domestic goats and mountain goats from 11 states. This will help determine if some strains are associated with more severe die-off events and explain some of the variability in severity. NOROCK researchers also provide quantitative support and disease ecology expertise to a team of researchers working on bighorn sheep pneumonia in the Hells Canyon metapopulation of ID, OR, and WA.
Below are publications associated with this project.
Pneumonia in bighorn sheep: Risk and resilience
Contact and contagion: Probability of transmission given contact varies with demographic state in bighorn sheep
Disease introduction is associated with a phase transition in bighorn sheep demographics
Costs and benefits of group living with disease: a case study of pneumonia in bighorn lambs (Ovis canadensis)
Use of exposure history to identify patterns of immunity to pneumonia in bighorn sheep (Ovis canadensis)
Spatio-temporal dynamics of pneumonia in bighorn sheep
- Overview
Bighorn sheep populations are often impacted by outbreaks of pneumonia that are suspected to come from domestic sheep and goats.
During the initial phases of these outbreaks large mortalities occur across all ages of bighorn sheep. During subsequent years, sporadic cases of pneumonia in adult bighorn sheep sometimes occur, but more importantly lambs continue to suffer disease, resulting in low recruitment and stagnant population growth. Pneumonia is one of the biggest hurdles limiting the comeback of bighorn sheep in western North America. A number of different pathogens are often detected during die-off events, which has made it difficult to determine if there is a causative agent that is behind most or all of the outbreaks. Recent evidence suggests that Mycoplasma ovipneumoniae (M. ovi.) is consistently associated with outbreaks and is often associated with a single strain in each outbreak suggesting a recent introduction.
One of our current projects is to genotype M. ovi. isolates from bighorn sheep, domestic sheep, domestic goats and mountain goats from 11 states. This will help determine if some strains are associated with more severe die-off events and explain some of the variability in severity. NOROCK researchers also provide quantitative support and disease ecology expertise to a team of researchers working on bighorn sheep pneumonia in the Hells Canyon metapopulation of ID, OR, and WA.
- Publications
Below are publications associated with this project.
Pneumonia in bighorn sheep: Risk and resilience
Infectious disease was an important driver of historic declines and extirpations of bighorn sheep (Ovis canadensis) in North America and continues to impede population restoration and management. Domestic sheep have long been linked to pneumonia outbreaks in bighorn sheep and this association has now been confirmed in 13 captive commingling experiments. However, ecological and etiological complexAuthorsE. Frances Cassirer, Kezia R. Manlove, Emily S. Almberg, Pauline Kamath, Mike Cox, Peregrine L. Wolff, Annette Roug, Justin M. Shannon, Rusty Robinson, Richard B. Harris, Ben J. Gonzales, Raina K. Plowright, Peter J. Hudson, Paul C. Cross, Andrew Dobson, Thomas E. BesserContact and contagion: Probability of transmission given contact varies with demographic state in bighorn sheep
Understanding both contact and probability of transmission given contact are key to managing wildlife disease. However, wildlife disease research tends to focus on contact heterogeneity, in part because the probability of transmission given contact is notoriously difficult to measure. Here, we present a first step towards empirically investigating the probability of transmission given contact in fAuthorsKezia R. Manlove, E. Frances Cassirer, Raina K. Plowright, Paul C. Cross, Peter J. HudsonDisease introduction is associated with a phase transition in bighorn sheep demographics
Ecological theory suggests that pathogens are capable of regulating or limiting host population dynamics, and this relationship has been empirically established in several settings. However, although studies of childhood diseases were integral to the development of disease ecology, few studies show population limitation by a disease affecting juveniles. Here, we present empirical evidence that disAuthorsKezia Manlove, E. Frances Cassirer, Paul C. Cross, Raina K. Plowright, Peter J. HudsonCosts and benefits of group living with disease: a case study of pneumonia in bighorn lambs (Ovis canadensis)
Group living facilitates pathogen transmission among social hosts, yet temporally stable host social organizations can actually limit transmission of some pathogens. When there are few between-subpopulation contacts for the duration of a disease event, transmission becomes localized to subpopulations. The number of per capita infectious contacts approaches the subpopulation size as pathogen infectAuthorsKezia R. Manlove, E. Frances Cassirer, Paul C. Cross, Raina K. Plowright, Peter J. HudsonUse of exposure history to identify patterns of immunity to pneumonia in bighorn sheep (Ovis canadensis)
Individual host immune responses to infectious agents drive epidemic behavior and are therefore central to understanding and controlling infectious diseases. However, important features of individual immune responses, such as the strength and longevity of immunity, can be challenging to characterize, particularly if they cannot be replicated or controlled in captive environments. Our research on bAuthorsRaina K. Plowright, Kezia Manlove, E. Frances Cassirer, Thomas H. Besser, Peter J. HudsonSpatio-temporal dynamics of pneumonia in bighorn sheep
Bighorn sheep mortality related to pneumonia is a primary factor limiting population recovery across western North America, but management has been constrained by an incomplete understanding of the disease. We analysed patterns of pneumonia-caused mortality over 14 years in 16 interconnected bighorn sheep populations to gain insights into underlying disease processes. 2. We observed four age-strucAuthorsE. Frances Cassirer, Raina K. Plowright, Kezia R. Manlove, Paul C. Cross, Andrew P. Dobson, Kathleen A. Potter, Peter J. Hudson