Respiratory disease, behavior, and survival of mountain goat kids

Abstract

Bacterial pneumonia is a threat to bighorn sheep (Ovis canadensis) populations. Bighorn sheep in the East Humboldt Mountain Range (EHR), Nevada, USA, experienced a pneumonia epizootic in 2009–2010. Testing of mountain goats (Oreamnos americanus) that were captured or found dead on this range during and after the epizootic detected bacteria commonly associated with bighorn sheep pneumonia die‐offs. Additionally, in years subsequent to the bighorn sheep epizootic, the mountain goat population had low kid:adult ratios, a common outcome for bighorn sheep populations that have experienced a pneumonia epizootic. We hypothesized that pneumonia was present and negatively affecting mountain goat kids in the EHR. From June–August 2013–2015, we attempted to observe mountain goat kids with marked adult females in the EHR at least once per week to document signs of respiratory disease; identify associations between respiratory disease, activity levels, and subsequent disappearance (i.e., death); and estimate weekly survival. Each time we observed a kid with a marked adult female, we recorded any signs of respiratory disease and collected behavior data that we fit to a 3‐state discrete hidden Markov model (HMM) to predict a kid's state (active vs. sedentary) and its probability of disappearing. We first observed clinical signs of respiratory disease in kids in late July–early August each summer. We observed 8 of 31 kids with marked adult females with signs of respiratory disease on 13 occasions. On 11 of these occasions, the HMM predicted that kids were in the sedentary state, which was associated with increased probability of subsequent death. We estimated overall probability of kid survival from June–August to be 0.19 (95% CI = 0.08–0.38), which was lower than has been reported in other mountain goat populations. We concluded that respiratory disease was present in the mountain goat kids in the EHR and negatively affected their activity levels and survival. Our results raise concerns about potential effects of pneumonia to mountain goat populations and the potential for disease transmission between mountain goats and bighorn sheep where the species are sympatric. © 2018 This article is a U.S. Government work and is in the public domain in the USA.

Genetic structure of Mycoplasma ovipneumoniae informs pathogen spillover dynamics between domestic and wild Caprinae in the western United States

“…However, the degree and direction of transmission remains unclear, and dynamics of the disease in mountain goats, until recently, has been largely overlooked. In the East Humboldt Range and Ruby Mountains of Nevada, M. ovipneumoniae infections and signs of respiratory disease were documented in mountain goats simultaneous to outbreaks in sympatric bighorn sheep, which resulted in decreased kid survival 52,53 . Strain typing in this region identified mountain goats as a source of infection to reintroduced naïve bighorn sheep following close associations between the two species 54 , data that are represented in our study as strain MTG-1/BHS-48.…”

Restoration of a bighorn sheep population impeded by Mycoplasma ovipneumoniae exposure

“…This is consistent with previous studies that have identified M. ovipneumoniae as the primary etiologic agent for epizootic pneumonia in bighorn sheep (Besser et al ). Similar extensive bighorn sheep mortality events have been documented as early as 1924 (Marsh ), but more recently in multiple studies on bighorn sheep (Festa‐Bianchet ; Cassirer & Sinclair ; Besser et al ; Smith et al ), as well as mountain goats (Blanchong et al ), and their susceptibility to M. ovipneumoniae . The strain of M. ovipneumoniae found in the translocated Deadwood bighorn sheep ( n = 3) post‐release differed from M. ovipneumoniae strains previously discovered within populations of bighorn sheep, domestic sheep, and mountain goats occupying varying regions of the Black Hills.…”

“…This is consistent with previous studies that have identified M. ovipneumoniae as the primary etiologic agent for epizootic pneumonia in bighorn sheep (Besser et al 2012). Similar extensive bighorn sheep mortality events have been documented as early as 1924 (Marsh 1938), but more recently in multiple studies on bighorn sheep (Festa-Bianchet 1988;Cassirer & Sinclair 2010;Besser et al 2012;Smith et al 2014), as well as mountain goats (Blanchong et al 2018), and We were unable to assess the efficacy of the vaccine administered at capture, as we were unable to obtain sufficient heart blood from carcasses to evaluate titers for M. ovipneumoniae (cELISA). The strain of M. ovipneumoniae utilized in the vaccine development was not observed in the Deadwood bighorn sheep; the vaccine may not have induced an antibody response, induced antibodies may not have been protective, antibody levels may have diminished between inoculation and exposure, or antibodies may not have been protective across strains.…”

A Survey of Bacterial Respiratory Pathogens in Native and Introduced Mountain Goats (Oreamnos americanus)

“…The difficulty in studying mountain goats presents a number of challenges in documenting cause-specific declines, which can include anthropogenic causes or predation (Côté and Festa-Bianchet 2003). While driv-ing factors are regionally specific, recent documentation of pneumonia in adult and kid mountain goats in Nevada (Wolff et al 2014;Anderson et al 2016) highlights the susceptibility of mountain goats to pneumonia pathogens typically associated with bighorn sheep (Ovis canadensis) epizootics (Blanchong et al 2018;Cassirer et al 2018). Given the broad distribution of respiratory pathogens in bighorn sheep (Butler et al 2017), susceptibility of mountain goats to epizootics may be a more-widespread cause for concern.…”

“…Given the broad distribution of respiratory pathogens in bighorn sheep (Butler et al 2017), susceptibility of mountain goats to epizootics may be a more-widespread cause for concern. Moreover, where mountain goats are sympatric with bighorn sheep there is strong niche overlap (Lowrey et al 2018) and potential for interspecific disease transmission (Wolff et al 2016;Blanchong et al 2018). Resident pathogen communities of mountain goats are poorly characterized yet have important implications for management and conservation of both mountain ungulate species.…”