virus

Most tests for viruses aim to detect only one or two. But researchers can now check a drop of blood for antibodies to hundreds of viruses, tracing the history of a lifetime of infections, old and new.

Scientists studying HIV and Ebola have noticed another virus hitching along for the ride in some blood samples. Now they're trying to figure out whether the lurker helps the body fend off disease.

A handful of ecologists knew for years that West Africa was at risk for an Ebola outbreak. Now they're figuring out where else in the world the virus could be hiding. Many signs point to Asia.

While some Americans worried that Ebola would spread around the U.S., a new mosquito-borne virus flew right in. It sickened more than 2,000 Americans and nearly a million people across the Caribbean.

Big questions have bedeviled virus hunters for 38 years: Why do people differ in their response to Ebola? Is it becoming more or less dangerous? There's now more evidence about who gets sick and why.