The first U.S. case of Marburg hemorraghic fever has been confirmed in Colorado, U.S. authorities have said.

Researchers may be able to tinker with a single amino acid of an enzyme that helps viruses multiply to render them harmless, according to molecular biologists who say the discovery could pave the way for a fast and cheap method of making vaccines.

Analyzing 30 years of data detailing a large rabies virus outbreak among North American raccoons, researchers at Emory University have revealed how initial demographic, ecological and genetic processes simultaneously shaped the virus's geographic spread over time. The study appears online in the Proceedings of The National Academy of Sciences.