Blast sparks fire at Russian laboratory housing smallpox virus

Facility know as Vector is one of only two sites holding virus, and also houses Ebola samples

A gas explosion has sparked a fire at a Russian laboratory complex stockpiling viruses ranging from smallpox to Ebola, authorities have said.

The State Research Centre of Virology and Biotechnology denied that the fire had exposed the public to the pathogens stored inside, some of the deadliest on Earth.