Mycoplasma ovipneumoniae detection in pneumonic mountain goat kids with transmission to sympatric bighorn sheep

In 2009-10, Rocky Mountain bighorn sheep (Ovis c. canadensis) in the adjacent East Humboldt Range (EHR) and Ruby Mountains (RM) of northeast Nevada suffered an all-age pneumonia die-off with an estimated loss of 90% in each... [ view full abstract ]

In 2009-10, Rocky Mountain bighorn sheep (Ovis c. canadensis) in the adjacent East Humboldt Range (EHR) and Ruby Mountains (RM) of northeast Nevada suffered an all-age pneumonia die-off with an estimated loss of 90% in each herd. Sympatric mountain goats (Oreamnos americanus) also experienced pneumonia with a 10-20% loss in both herds. The same strain of Mycoplasma ovipneumoniae (M. ovi) was confirmed as a contributing pathogen in both species and ranges. After removal of the surviving 15 sheep, 20 bighorns from Alberta, Canada were translocated to the EHR in 2013. Nasal swabs from all animals were negative for M. ovi by ELISA and Real time (RT)-PCR at translocation (n=20) and during subsequent sampling in 2014 (n=7) and 2015 (n=13). Concurrent sampling of EHR goats for M. ovi by RT-PCR indicated a prevalence of 6% (n=15), 12% (n=16) and 18% (n=11), respectively. Annual winter aerial surveys from 2010-15 indicated kid ratios ranged from 0-17 per 100 adults (x ̅ = 7) with an estimated λ of 0.60 for the herd. Tracking of both species during summer 2014 and 2015 recovered 5 kid mortalities. Gross and histologic lesions were consistent with polymicrobial bronchopneumonia and M. ovi was detected in the lungs with real-time PCR. During the summer, mountain goats and bighorn sheep were observed in close proximity (<2m). In September 2015, clinical signs of respiratory disease were noted in the bighorns and multiple mortalities were observed through December. M. ovi was identified in pneumonic lungs and multi-locus DNA sequencing confirmed the strain matched that isolated from the mountain goats. Our results suggest that M. ovi may negatively affect recruitment in mountain goats as has been documented for bighorn sheep. Our findings also indicate that potential disease transmission between mountain goats and bighorn sheep should be considered where range overlap occurs.