Alpha-coronavirus Shedding in the Reunion Free-tailed Bat (Mormopterus francoismoutoui)

Deciphering the biological and ecological drivers of virus transmission in wildlife requires specific molecular diagnostic tools. Understanding viral shedding routes, loads, and particle infectivity is crucial for assessing transmission dynamics in reservoir hosts and spillover potential to other species, including humans. We investigated coronavirus (CoV) shedding patterns in the endemic Molossid bat species Mormopterus francoismoutoui on Reunion Island. We tested 1,326 fresh feces with two PCR assays: a pan-CoV multiprobe real-time PCR and a quantitative PCR (qPCR) targeting the RdRp gene of the alpha-CoV previously described in M. francoismoutoui. Both assays showed strong agreement, although the qPCR detected 1.55 times more positives. Temporal variation in CoV shedding prevalence was consistent across assays, and no significant differences in RdRp gene copy numbers were observed between adult females and juveniles. Urbanization may increase Molossid bats interactions with humans, livestock, and synanthropic species; a comprehensive assessment of spillover potential of Molossid-associated alpha-CoVs is therefore critical.