well... it started off from China!
reasons expert gave :
First reason : From animals... this virus could only spread around
the animal kingdom ( exclude human ) , but this virus got too
strong till childrens are infected , then the adults...
Second reason : China's experiment on chemical warfare , they were
trying to come out with this virus that can be used in chemical
warfare , but who knows how the virus got out and started spreading
to people in Guang Zhou then to other parts of China and then to
the rest of the world....