Tested archived and contemporary dromedary-camel sera from Oman and Spain (plus other regions in follow-on work) for MERS-CoV neutralising antibodies using protein-microarray and virus-neutralization assays. All 50 Omani camel sera were seropositive (100%), versus 15/105 (14%) Spanish camel sera, indicating widespread, geographically variable MERS-CoV (or closely related virus) circulation in camel populations predating recognition of the human MERS outbreak. relevance_note: the founding evidence for the second major precedent case (alongside SARS-1/civets) the zoonosis side cites — a live-animal-trade species carrying a directly ancestral virus at high seroprevalence well before its role in human spillover was recognized, and the template for how a natural intermediate-host link gets established serologically rather than by an outbreak investigation alone.