ST. LOUIS -- Even as scientists were confirming that the West Nile virus had reached St. Louis, researchers here already have been trying to pinpoint why the mosquito-transmitted form of encephalitis ...

The development raises the obvious question. What is hantavirus, and should we be worried?

Viruses have no metabolism of their own and must therefore infect host cells in order to replicate. Contact between the virus and the cell surface is a crucial first step, which can also prevent ...