Lots of new diseases are emerging and diseases were once local are now global," says Roman, a wildlife expert and fellow at UVM's Gund Institute for Ecological Economics. Diseases like West Nile Virus have spread around the world very quickly."

This is not the first time humans have faced a raft of new diseases. About 10,000 years ago, humans invented farming. This move from hunting to agriculture brought permanent settlements, domestication of animals, and changes in diet. It also brought new infectious diseases, in what scientists call an epidemiologic transition."

People have been working on this in individual diseases but no one has put all the studies together to compare them. In 2006, he and Pongsiri gathered a group of scientists and policy analysts with expertise in a range of the new diseases being observed -- including West Nile virus as well as malaria, the African parasitic disease schistosomiasis, hantavirus pulmonary syndrome, and several others. From that meeting, the forthcoming BioScience study developed.

Historically, Lyme disease was probably rare, because you had a large range of mammals, everything from pumas all the way down to a widespread community of rodents, says Roman. Ticks feed on different species, and, since many are poor hosts for the bacterium, only a limited number of ticks would carry the disease to people. But fragmentation and reduction of forests has led to deep declines in the number of mammals -- and white-footed mice tend to thrive in species-poor places, like small patches of forest on the edge of neighborhoods.

Regards
Calvin Parker
Editorial Assistance
Journal of infectious disease and dignosis