Postepizootic Persistence of Asymptomatic Mycoplasma conjunctivae Infection in Iberian Ibex

The susceptibility of the Iberian ibex (Capra pyrenaica ) toMycoplasma conjunctivae ocular infection and the changes in their interaction over time were studied in terms of clinical outcome, molecular detection, and IgG immune response in a captive population that underwent a severe infectious keratoconjunctivitis (IKC) outbreak.Mycoplasma conjunctivae was detected in the Iberian ibex, coinciding with the IKC outbreak. Its prevalence had a decreasing trend in 2013 that was consistent with the clinical resolution (August, 35.4%; September, 8.7%; November, 4.3%). Infections without clinical outcome were, however, still detected in the last handling in November. Sequencing and cluster analyses of theM. conjunctivae strains found 1 year later in the ibex population confirmed the persistence of the same strain lineage that caused the IKC outbreak but with a high prevalence (75.3%) of mostly asymptomatic infections and with lower DNA load ofM. conjunctivae in the eyes (mean quantitative PCR [qPCR] cycle threshold [CT ], 36.1 versus 20.3 in severe IKC). Significant age-related differences ofM. conjunctivae prevalence were observed only under IKC epizootic conditions. No substantial effect of systemic IgG onM. conjunctivae DNA in the eye was evidenced with a linear mixed-models selection, which indicated that systemic IgG does not necessarily drive the resolution ofM. conjunctivae infection and does not explain the epidemiological changes observed. The results show how both epidemiological scenarios, i.e., severe IKC outbreak and mostly asymptomatic infections, can consecutively occur by entailing mycoplasma persistence.IMPORTANCE Mycoplasma infections are reported in a wide range of epidemiological scenarios that involve severe disease to asymptomatic infections. This study allows a better understanding of the transition between two differentMycoplasma conjunctivae epidemiological scenarios described in wild host populations and highlights the ability ofM. conjunctivae to adapt, persist, and establish diverse interactions with its hosts. The proportion of asymptomatic and clinicalM. conjunctivae infections in a host population may not be regarded only in response to intrinsic host species traits (i.e., susceptibility) but also to a specific host-pathogen interaction, which in turn influences the infection dynamics. Both epidemic infectious keratoconjunctivitis and a high prevalence of asymptomaticM. conjunctivae infections may occur in the same host population, depending on the circulation ofM. conjunctivae , its maintenance, and the progression of the host-pathogen interactions.