Guanarito virus is a member of the family Arenaviridae, which includes enveloped viruses with a segmented, negative-strand RNA genome. It is found in Venezuela where it is transmitted to humans from rats. The natural host is believed to be the short-tailed cane mouse. In humans the virus causes hemorrhagic fever with a case fatality rate of 23%. The virus does not transmit among humans and is not known to replicate in US rodents. Other viruses that cause hemorrhagic fevers include filoviruses, bunyaviruses, and flaviviruses.
It is believed that the missing vial of virus was inadvertently destroyed within the facility.
For an inside view of a BSL-4 laboratory, including a discussion of how virus stocks are secured, don’t miss ‘Threading the NEIDL‘, a documentary that explores the working of a similar facility in Boston, MA.