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Sanchez JN, Munk BA, Colby J, Torres SG, Gonzales BJ, DeForge JR, Byard AJ, Konde L, Shirkey NJ, Pandit PS, Botta RA, Roug A, Ziccardi MH, Johnson CK. Pathogen surveillance and epidemiology in endangered Peninsular bighorn sheep ( Ovis canadensis nelsoni). CONSERVATION SCIENCE AND PRACTICE 2022; 4:e12820. [PMID: 36590384 PMCID: PMC9799158 DOI: 10.1111/csp2.12820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 08/22/2022] [Indexed: 11/05/2022] Open
Abstract
Peninsular bighorn sheep (Ovis canadensis nelsoni) are found exclusively in Southern California and Baja Mexico. They are federally endangered due to multiple threats, including introduced infectious disease. From 1981 - 2017, we conducted surveillance for 16 pathogens and estimated population sizes, adult survival, and lamb survival. We used mixed effects regression models to assess disease patterns at the individual and population levels. Pathogen infection/exposure prevalence varied both spatially and temporally. Our findings indicate that the primary predictor of individual pathogen infection/exposure was the region in which an animal was captured, implying that transmission is driven by local ecological or behavioral factors. Higher Mycoplasma ovipneumoniae seropositivity was associated with lower lamb survival, consistent with lambs having high rates of pneumonia-associated mortality, which may be slowing population recovery. There was no association between M. ovipneumoniae and adult survival. Adult survival was positively associated with population size and parainfluenza-3 virus seroprevalence in the same year, and orf virus seroprevalence in the previous year. Peninsular bighorn sheep are recovering from small population sizes in a habitat of environmental extremes, compounded by infectious disease. Our research can help inform future pathogen surveillance and population monitoring for the long-term conservation of this population.
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Affiliation(s)
- Jessica N. Sanchez
- EpiCenter for Disease Dynamics, One Health Institute, School of Veterinary Medicine, University of California at Davis, 1089 Veterinary Medicine Dr, Davis, California, USA 95616
| | - Brandon A. Munk
- Wildlife Health Lab, California Department of Fish and Wildlife, 1701 Nimbus Rd, Rancho Cordova, CA, USA 95670
| | - Janene Colby
- California Department of Fish and Wildlife, South Coast Region, 3883 Ruffin Rd, San Diego, CA, USA 92123
| | - Steve G. Torres
- Wildlife Health Lab, California Department of Fish and Wildlife, 1701 Nimbus Rd, Rancho Cordova, CA, USA 95670
| | - Ben J. Gonzales
- Wildlife Health Lab, California Department of Fish and Wildlife, 1701 Nimbus Rd, Rancho Cordova, CA, USA 95670
| | | | - Aimee J. Byard
- Bighorn Institute, P.O. Box 262, Palm Desert, CA, USA 92261
| | - Lora Konde
- Wildlife Health Lab, California Department of Fish and Wildlife, 1701 Nimbus Rd, Rancho Cordova, CA, USA 95670
| | - Nicholas J. Shirkey
- Wildlife Health Lab, California Department of Fish and Wildlife, 1701 Nimbus Rd, Rancho Cordova, CA, USA 95670
| | - Pranav S. Pandit
- EpiCenter for Disease Dynamics, One Health Institute, School of Veterinary Medicine, University of California at Davis, 1089 Veterinary Medicine Dr, Davis, California, USA 95616
| | - Randy A. Botta
- California Department of Fish and Wildlife, South Coast Region, 3883 Ruffin Rd, San Diego, CA, USA 92123
| | - Annette Roug
- Centre for Veterinary Wildlife Research, Department of Production Animal Medicine, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Onderstepoort, Pretoria 0110, South Africa
| | - Michael H. Ziccardi
- One Health Institute, School of Veterinary Medicine, University of California at Davis, 1089 Veterinary Medicine Dr, Davis, California, USA 95616
| | - Christine K. Johnson
- EpiCenter for Disease Dynamics, One Health Institute, School of Veterinary Medicine, University of California at Davis, 1089 Veterinary Medicine Dr, Davis, California, USA 95616
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How Respiratory Pathogens Contribute to Lamb Mortality in a Poorly Performing Bighorn Sheep ( Ovis canadensis ) Herd. J Wildl Dis 2016; 53:126-130. [PMID: 27690193 DOI: 10.7589/2016-05-097] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We evaluated bighorn sheep ( Ovis canadensis ) ewes and their lambs in captivity to examine the sources and roles of respiratory pathogens causing lamb mortality in a poorly performing herd. After seven consecutive years of observed December recruitments of <10%, 13 adult female bighorn sheep from the remnant Gribbles Park herd in Colorado, US were captured and transported to the Thorne-Williams Wildlife Research Center in Wyoming in March 2013. Ewes were sampled repeatedly over 16 mo. In April 2014, ewes were separated into individual pens prior to lambing. Upon death, lambs were necropsied and tested for respiratory pathogens. Six lambs developed clinical respiratory disease and one lamb was abandoned. Pathology from an additional six lambs born in 2013 was also evaluated. Mycoplasma ovipneumoniae , leukotoxigenic Mannheimia spp., leukotoxigenic Bibersteinia trehalosi , and Pasteurella multocida all contributed to lamb pneumonia. Histopathology suggested a continuum of disease, with lesions typical of pasteurellosis predominating in younger lambs and lesions typical of mycoplasmosis predominating in older lambs. Mixed pathology was observed in lambs dying between these timeframes. We suspected that all the ewes in our study were persistently infected and chronically shedding the bacteria that contributed to summer lamb mortality.
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