and we think based on our analysis of the sequence of this virus also originated in a bat. >> reporter: where? >> probably somewhere in the middle east. >> reporter: health officials don't know much about how the virus spreads. but at this point, travel warnings have not been issued. >> i don't think we should be concerned in terms of travel to the middle east or anywhere in the world right now. but be aware of it. most cases of illness are associated with the elderly and those with preexisting or severe underlying medical conditions. >> one of the big reasons for concern, right now, there is no known treatment and no way to make a vaccine. but doctors are currently working on that. >> no known treatment, that's scary. >> and it's called the middle east respiratory syndrome. yet they are calling it a global threat as well. what's the difference here? >> it seems to go against the message that world health organization was trying to get out this week, but because all of these cases traced to the