Long-term dynamics of <i>Mycoplasma conjunctivae</i> at the wildlife-livestock interface in the Pyrenees

<div><p>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 <i>Mycoplasma conjunctivae</i> was investigated in all host populations from six study areas in the Pyrenees and one in the Cantabrian Mountains (Northern Spain). Detection of <i>M</i>. <i>conjunctivae</i> 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. <i>Mycoplasma conjunctivae</i> was consistently detected in three Pyrenean chamois (<i>Rupicapra p</i>. <i>pyrenaica</i>) populations, as well as in sheep flocks (17.0% of sheep) and occasionally in mouflon (<i>Ovis aries musimon</i>) 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 <i>M</i>. <i>conjunctivae</i> 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 <i>M</i>. <i>conjunctivae</i> 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 <i>M</i>. <i>conjunctivae</i> 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 <i>M</i>. <i>conjunctivae</i> to establish diverse interactions and persist in host populations, also with different transmission conditions.</p>