Questions complicate efforts to contain new virus from China

This image provided by The National Institute of Allergy and Infectious Diseases (NIAID). This scanning electron microscope image shows SARS-CoV-2 (orange)—also known as 2019-nCoV, the virus that causes COVID-19—isolated from a patient in the U.S., emerging from the surface of cells (green) cultured in the lab. (NIAID-RML via AP)

WASHINGTON — Reports one day suggest the respiratory outbreak in China might be slowing, the next brings word of thousands more cases. Even the experts have whiplash in trying to determine if the epidemic is getting worse, or if a backlog of the sick is finally getting counted.