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Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock.

ABSTRACT: Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (∼3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations.

SUBMITTER: Kamath PL

PROVIDER: S-EPMC4865865 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

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Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock.

Kamath Pauline L PL Foster Jeffrey T JT Drees Kevin P KP Luikart Gordon G Quance Christine C Anderson Neil J NJ Clarke P Ryan PR Cole Eric K EK Drew Mark L ML Edwards William H WH Rhyan Jack C JC Treanor John J JJ Wallen Rick L RL White Patrick J PJ Robbe-Austerman Suelee S Cross Paul C PC

Nature communications 20160511

Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced int ...[more]

PMID: 27165544

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Project description:Functional roles of domestic and wild host populations in infectious keratoconjunctivitis (IKC) epidemiology have been extensively discussed claiming a domestic reservoir for the more susceptible wild hosts, however, based on limited data. With the aim to better assess IKC epidemiology in complex host-pathogen alpine systems, the long-term infectious dynamics and molecular epidemiology of Mycoplasma conjunctivae was investigated in all host populations from six study areas in the Pyrenees and one in the Cantabrian Mountains (Northern Spain). Detection of M. conjunctivae was performed by qPCR on 3600 eye swabs collected during seven years from hunted wild ungulates and sympatric domestic sheep (n = 1800 animals), and cluster analyses of the strains were performed including previous reported local strains. Mycoplasma conjunctivae was consistently detected in three Pyrenean chamois (Rupicapra p. pyrenaica) populations, as well as in sheep flocks (17.0% of sheep) and occasionally in mouflon (Ovis aries musimon) from the Pyrenees (22.2% in one year/area); statistically associated with ocular clinical signs only in chamois. Chamois populations showed different infection dynamics with low but steady prevalence (4.9%) and significant yearly fluctuations (0.0%- 40.0%). Persistence of specific M. conjunctivae strain clusters in wild host populations is demonstrated for six and nine years. Cross-species transmission between chamois and sheep and chamois and mouflon were also sporadically evidenced. Overall, independent M. conjunctivae sylvatic and domestic cycles occurred at the wildlife-livestock interface in the alpine ecosystems from the Pyrenees with sheep and chamois as the key host species for each cycle, and mouflon as a spill-over host. Host population characteristics and M. conjunctivae strains resulted in different epidemiological scenarios in chamois, ranging from the fading out of the mycoplasma to the epidemic and endemic long-term persistence. These findings highlight the capacity of M. conjunctivae to establish diverse interactions and persist in host populations, also with different transmission conditions.

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Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock.

Publications

Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock.

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