Traces of history conserved over 600 years in the geographic distribution of genetic variants of an RNA virus: Bovine viral diarrhea virus in Switzerland.
The first records of smallpox and rabies southwestern aztec rug date back thousands of years and foot-and-mouth disease in cattle was described in the 16th century.These diseases stood out by their distinct signs, dramatic way of transmission from rabid dogs to humans, and sudden appearance in cattle herds.By contrast, infectious diseases that show