Data from: Bighorn sheep show similar in-host responses to the same pathogen strain in two contrasting environments

Ecological context – the biotic and abiotic environment, along with its influence on population mixing dynamics and individual susceptibility – are thought to have major bearing on epidemic outcomes. However, direct comparisons of disease events in contrasting ecological contexts in wildlife systems are often confounded by concurrent differences in host genetics, exposure histories, or pathogen strains. Here, we compare disease dynamics of a Mycoplasma ovipneumoniae spillover event that affected bighorn sheep populations in two contrasting ecological contexts. One event occurred on the herd’s home range near the Rio Grande Gorge in New Mexico, while the other occurred in a captive facility at Hardware Ranch in Utah. While data collection regimens varied between the two sites, general patterns of antibody signal strength and symptom emergence were consistent. Symptoms appeared in the captive setting an average of 12.9 days post-exposure, average time to seroconversion was 24.9 days, and clinical signs peaked at approximately 36 days post-infection. These patterns were consistent with serological testing and subsequent declines in symptom intensity in the free-ranging herd. At the captive site, older animals exhibited more severe declines in body condition and loin thickness, higher symptom burdens, and slower antibody response to the pathogen than younger animals. Younger animals were more likely than older animals to clear infection by the time of sampling at both sites. The patterns presented here suggest that environment may not be a major determinant of epidemiological outcomes in the bighorn sheep - M. ovipneumoniae system, elevating the possibility that host- or pathogen-factors may be responsible for observed variation.