Good information on blackpox, background on who has the virus, discounts the notion that only US and Russia have access to it.
Statement for the Record by Richard Preston Before The Senate Judiciary Subcommittee on Technology, Terrorism & Government Information and the Senate Select Committee on Intelligence:
Chemical and Biological Weapons Threats to America: Are We Prepared?
This is from April, 1998. Contains information about blackpox. One section in particular caught my attention:
In a military release of smallpox, the victims would be receiving extremely high doses of smallpox, far higher than in a natural outbreak, and we can suspect that many of the victims would be developing blackpox and having smallpox bleedouts. Blackpox is even more contagious than so-called ordinary smallpox.