A new Covid-19 variant called NB.1.8.1, or Nimbus, represents about a third of new US Covid-19 cases. Dr. Leana Wen answers ...

New viruses that are genetically similar to known fatal viruses have been discovered near food sources in a concerning new ...

Twenty new viruses have been discovered within bats in China, "raising urgent concerns" that these diseases might spill over ...

The World Health Organization’s expert group says the origin of COVID-19 remains inconclusive, though most evidence still ...

Bats living among the orchards of Yunnan province in southwest China have been found harboring a variety of unknown pathogens ...

An expert group charged by the World Health Organization to investigate the origins of the COVID-19 pandemic has found no ...

The World Health Organization said on Friday that efforts to determine the origins of SARS-CoV-2, the virus that caused the ...