Another interesting fact: Essentially every camel in Saudi Arabia either has MERS antibodies or is carrying the virus itself. They are the animal reservoir. Every human case can be traced back to a camel. Like SARS-COV2 except 35% lethal! Another big difference is humans tend not to spread it to other humans. SARS was a spillover of a bat virus through civets, and then into humans. HIV was a spillover from chimps. Ebola was a spillover from monkeys or apes (and again a bat virus).
Zoonotic spillovers happen all the time! Considering there is no actual evidence SARS-COV2 was a lab creation, virologists think it was just another natural spillover. It might take a decade or two to find the bat virus. Not unusual, because there are a LOT of different bats all over the world, and collecting throat swabs from them and sequencing them is difficult, dangerous, and costly.
A big part of the problem now is humans keep on getting on airplanes and spreading viruses around the world. For example: MERS case in South Korea, with the virus sequenced and found identical with a camel MERS variant.
We're flying electric helicopters on Mars yet you can't turn on your clothes dryer in Texas. That's because scientists are in charge of Mars, and Republicans are in charge of Texas.