NEW YORK (GenomeWeb) – The Lassa virus, unlike its Ebola cousin, appears to have ancient origins and its appearances in humans seem to mostly be due to reservoir-to-human transmissions, according to an analysis of some 200 Lassa virus sequences.

"The reason Lassa hasn't yet grown into this huge epidemic is because there is limited transmission between humans," first author Kristian Andersen from the Scripps Research Institute said in a statement. "That's a major difference between Lassa virus and Ebola virus."