Independent Discovery of Mesomycoplasma conjunctivae in Non-Native Aoudad (Ammotragus lervia) in Texas

Abstract

Simple Summary A continual outbreak of infectious keratoconjunctivitis (IKC) in non-native, free-ranging populations of aoudad (Ammotragus lervia) in western Texas has been reported since December 2025. It seemed prudent to revisit samples obtained from the last 6–8 years to identify if this is truly a new or an undetected bacterial pathogen that has been circulating for some time. Herein, we combined a newly generated microbiome dataset with previous findings using 16S rRNA sequencing. Five haplotypes of Mesomycoplasma conjunctivae were identified using an alignment of 406 bp in aoudad populations in the Carrizo, Chinati, Sierra Vieja, and Van Horn mountains between 2018 and 2020. The aoudad-like M. conjunctivae is most genetically similar to a strain of M. conjunctivae sourced from a moose. Interestingly, both wildlife strains of M. conjunctivae grouped in a clade sister to strains of M. conjunctivae from domestic goats, suggesting that there may be a phylogenetic relationship between the bacteria and host and divergence between wildlife and livestock strains of M. conjunctivae. Because aoudad live in sympatry with native desert bighorn sheep (DBS), a highly prioritized conservation management species, it is imperative to opportunistically sample IKC-affected aoudad to determine the bacterial cause of disease and prepare a plan for medicinal intervention if IKC is transmitted into DBS populations.