Thanks for the response, datura. If there really is a new strain of Ebola in PRC, I doubt very much that it was created by the Chinese government as a bioweapon. For one thing, I doubt that any government knows how to protect its own population against Ebola. And I certainly doubt that any nation's science is so advanced that it could modify a disease so as to make it affect only specific ethnic groups!
Out of curiousity, does anyone know of an existing infectious disease that only affects certain ethnic groups? They may be out there, but I can't think of any. The illnesses I can think of that seem to discriminate by ethnicity or geography are all considered to be linked to heredity, environment, or diet, rather than to pathogens.
Did SARS kill any caucasians? Or was it "Asian only"?
There are many diseases for which the susceptibility varies greatly among ethnic groups, due to differences in genetics and point mutation distribution. For obvious reasons, there is no "perfect" isolation. For a cheap example, there is the well-documented genetic resistance/immunity of some northern European caucasians to HIV. Protections against infectious disease like this are never universal for an ethnic group, but it does generate significant differences in transmission and infection rates.