Dataset Information

Exposure of bighorn sheep to domestic goats colonized with Mycoplasma ovipneumoniae induces sub-lethal pneumonia.

ABSTRACT:

Background

Bronchopneumonia is a population limiting disease of bighorn sheep (Ovis canadensis) that has been associated with contact with domestic Caprinae. The disease is polymicrobial but is initiated by Mycoplasma ovipneumoniae, which is commonly carried by both domestic sheep (O. aries) and goats (Capra aegagrus hircus). However, while previous bighorn sheep comingling studies with domestic sheep have resulted in nearly 100% pneumonia mortality, only sporadic occurrence of fatal pneumonia was reported from previous comingling studies with domestic goats. Here, we evaluated the ability of domestic goats of defined M. ovipneumoniae carriage status to induce pneumonia in comingled bighorn sheep.

Methodology/principal findings

In experiment 1, three bighorn sheep naïve to M. ovipneumoniae developed non-fatal respiratory disease (coughing, nasal discharge) following comingling with three naturally M. ovipneumoniae-colonized domestic goats. Gross and histological lesions of pneumonia, limited to small areas on the ventral and lateral edges of the anterior and middle lung lobes, were observed at necropsies conducted at the end of the experiment. A control group of three bighorn sheep from the same source housed in isolation during experiment 1 remained free of observed respiratory disease. In experiment 2, three bighorn sheep remained free of observed respiratory disease while comingled with three M. ovipneumoniae-free domestic goats. In experiment 3, introduction of a domestic goat-origin strain of M. ovipneumoniae to the same comingled goats and bighorn sheep used in experiment 2 resulted in clinical signs of respiratory disease (coughing, nasal discharge) in both host species. At the end of experiment 3, gross and histological evidence of pneumonia similar to that observed in experiment 1 bighorn sheep was observed in both affected bighorn sheep and domestic goats.

Conclusions/significance

M. ovipneumoniae strains carried by domestic goats were transmitted to comingled bighorn sheep, triggering development of pneumonia. However, the severity of the disease was markedly milder than that seen in similar experiments with domestic sheep strains of the bacterium.

SUBMITTER: Besser TE

PROVIDER: S-EPMC5462392 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Publications

Exposure of bighorn sheep to domestic goats colonized with Mycoplasma ovipneumoniae induces sub-lethal pneumonia.

Besser Thomas E TE Cassirer E Frances EF Potter Kathleen A KA Foreyt William J WJ

PloS one 20170607 6

<h4>Background</h4>Bronchopneumonia is a population limiting disease of bighorn sheep (Ovis canadensis) that has been associated with contact with domestic Caprinae. The disease is polymicrobial but is initiated by Mycoplasma ovipneumoniae, which is commonly carried by both domestic sheep (O. aries) and goats (Capra aegagrus hircus). However, while previous bighorn sheep comingling studies with domestic sheep have resulted in nearly 100% pneumonia mortality, only sporadic occurrence of fatal pne ...[more]

PMID: 28591169

Similar Datasets

Project description:Determining the demographic impacts of wildlife disease is complex because extrinsic and intrinsic drivers of survival, reproduction, body condition, and other factors that may interact with disease vary widely. Mycoplasma ovipneumoniae infection has been linked to persistent mortality in juvenile bighorn sheep (Ovis canadensis), although mortality appears to vary widely across subspecies, populations, and outbreaks. Hypotheses for that variation range from interactions with nutrition, population density, genetic variation in the pathogen, genetic variation in the host, and other factors. We investigated factors related to survival of juvenile bighorn sheep in reestablished populations in the northern Basin and Range ecosystem, managed as the formerly-recognized California subspecies (hereafter, "California lineage"). We investigated whether survival probability of 4-month juveniles would vary by (1) presence of M. ovipneumoniae-infected or exposed individuals in populations, (2) population genetic diversity, and (3) an index of forage suitability. We monitored 121 juveniles across a 3-year period in 13 populations in southeastern Oregon and northern Nevada. We observed each juvenile and GPS-collared mother semi-monthly and established 4-month capture histories for the juvenile to estimate survival. All collared adult females were PCR-tested at least once for M. ovipneumoniae infection. The presence of M. ovipneumoniae-infected juveniles was determined by observing juvenile behavior and PCR-testing dead juveniles. We used a known-fate model with different time effects to determine if the probability of survival to 4 months varied temporally or was influenced by disease or other factors. We detected dead juveniles infected with M. ovipneumoniae in only two populations. Derived juvenile survival probability at four months in populations where infected juveniles were not detected was more than 20 times higher. Detection of infected adults or adults with antibody levels suggesting prior exposure was less predictive of juvenile survival. Survival varied temporally but was not strongly influenced by population genetic diversity or nutrition, although genetic diversity within most study area populations was very low. We conclude that the presence of M. ovipneumoniae can cause extremely low juvenile survival probability in translocated bighorn populations of the California lineage, but found little influence that genetic diversity or nutrition affect juvenile survival. Yet, after the PCR+ adult female in one population died, subsequent observations found 11 of 14 ( 79%) collared adult females had surviving juveniles at 4-months, suggesting that targeted removals of infected adults should be evaluated as a management strategy.

Project description:Mycoplasma ovipneumoniae contributes to polymicrobial pneumonia in domestic sheep. Elucidation of host genetic influences of M. ovipneumoniae nasal detection has the potential to reduce the incidence of polymicrobial pneumonia in sheep through implementation of selective breeding strategies. Nasal mucosal secretions were collected from 647 sheep from a large US sheep flock. Ewes of three breeds (Polypay n = 222, Rambouillet n = 321, and Suffolk n = 104) ranging in age from one to seven years, were sampled at three different times in the production cycle (February, April, and September/October) over four years (2015 to 2018). The presence and DNA copy number of M. ovipneumoniae was determined using a newly developed species-specific qPCR. Breed (P<0.001), age (P<0.024), sampling time (P<0.001), and year (P<0.001) of collection affected log10 transformed M. ovipneumoniae DNA copy number, where Rambouillet had the lowest (P<0.0001) compared with both Polypay and Suffolk demonstrating a possible genetic component to detection. Samples from yearlings, April, and 2018 had the highest (P<0.046) detected DNA copy number mean. Sheep genomic DNA was genotyped with the Illumina OvineHD BeadChip. Principal component analysis identified most of the variation in the dataset was associated with breed. Therefore, genome wide association analysis was conducted with a mixed model (EMMAX), with principal components 1 to 6 as fixed and a kinship matrix as random effects. Genome-wide significant (P<9x10-8) SNPs were identified on chromosomes 6 and 7 in the all-breed analysis. Individual breed analysis had genome-wide significant (P<9x10-8) SNPs on chromosomes 3, 4, 7, 9, 10, 15, 17, and 22. Annotated genes near these SNPs are part of immune (ANAPC7, CUL5, TMEM229B, PTPN13), gene translation (PIWIL4), and chromatin organization (KDM2B) pathways. Immune genes are expected to have increased expression when leukocytes encounter M. ovipneumoniae which would lead to chromatin reorganization. Work is underway to narrow the range of these associated regions to identify the underlying causal mutations.

Project description:Abstract The mitochondrial genome has been used in numerous species to discern evolutionary patterns, phylogeny, and speciation. Previous studies including mitochondrial genome assemblies in bighorn and domestic sheep indicate variation between these two species. This variation can be used to determine whether animal tissue originates from bighorn or domestic species. In this study, we designed and validated an assay that uses amplification of two targets in the mitochondrial genome followed by short read sequencing to identify single nucleotide polymorphisms (SNPs) in bighorn and domestic sheep. Tissue samples were acquired from two Rocky Mountain bighorn sheep and two domestic sheep (Suffolk and Icelandic breeds), and mitochondrial DNA was extracted. A target designed on the Cytochrome B (CYTB) gene (266 base pairs in length) and a target on the NADH dehydrogenase subunit 6 (ND6) gene (328 base pairs in length) were amplified using PCR and sequenced with an Illumina Mi-Seq. Sequences were aligned to Ovis aries Oar_v4.0 mitochondrial reference (NC_001941.1) and Ovis canadensis mitochondrial reference (JN181255), and variants were called using CLC Genomics Workbench v11.0 with sequence depth of over 40X. Bighorn sheep sequences aligned to the domestic mitochondrial reference displayed 17 SNPs in each target, with a total of 34 SNPs and 94% sequence identity, while domestic sequences displayed 0–2 SNPs for both targets and 99–100% sequence identity. Bighorn sheep sequences aligned to the bighorn mitochondrial reference displayed 0 variants and 100% sequence identity, while domestic sheep sequences displayed 16–17 SNPs in each target, with 33–34 total SNPs identified and 94% sequence identity. The assay designed in this study and variants identified can be used to determine whether samples are of Ovis aries or Ovis canadensis origin. Further, these data provide additional insight into mitochondrial genome variation between two Ovisspecies; one domestic and one wild.

Dataset Information

Exposure of bighorn sheep to domestic goats colonized with Mycoplasma ovipneumoniae induces sub-lethal pneumonia.

Background

Methodology/principal findings

Conclusions/significance

Publications

Exposure of bighorn sheep to domestic goats colonized with Mycoplasma ovipneumoniae induces sub-lethal pneumonia.

Similar Datasets

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