[Feiny]

Impossible? No, but unlikely. The rate of contamination would be much higher. There would be thousands of cases....not hundreds.

[FreepForever]

1) There are already thousands, not hundreds. And, there could be tens of thousands in China now, who knows.
2) This virus is still under research. Probably they haven't got it right the first time.
3) Biological warfare agents are not designed to mass killing like bioweapon. Mathmatical models have shown that one "curable" patient can decapacitate another 4 persons (medical workers, civil services, supporting sectors). Therefore, if only 20% of the population is affected, the entire country is paralized.
4) Biological warfare agents is design to cause "curable" decease, not lethal decease. So that the enemy's government cannot abandon them and isolate the area to stop it from spreading. Burning bodies and their houses is not an option.
5) Biological warfare agent is design to cause an "economic meltdown". All tourism and commercial activities stopped. No government can withstand such loss for an extended period.