The CDC has issued new guidance for clinicians on screening patients for novel coronavirus (2019-nCoV) and caring for patients.

The update includes a new flowchart on identifying and assessing patients with potential coronavirus illness. For patients under investigation, they recommend testing upper respiratory samples from nasopharyngeal and oropharyngeal swabs, and lower respiratory samples should be tested for those with productive coughs. In other coronavirus news:

As of last count, China had 14,000 confirmed cases, including 300 deaths, according to the World Health Organisation. Over 25 countries and territories have patients with the virus.

A seventh case has been confirmed in the U.S. The patient recently traveled from Wuhan, China to California.

The White House declared a national public health emergency. American citizens who have been in China’s Hubei Province in the 2 weeks prior to their re-entry will have to undergo up to 14 days of mandatory quarantine upon returning to the U.S. Those returning from mainland China will have to undergo screening upon entry and then will have a monitored self-quarantine. The White House also decided to block entry of foreign nationals (other than immediate family of U.S. citizens and permanent residents) who have been to China in the past 2 weeks.

The Lancet published a modeling study that found that 2.68 people could be infected from one sick person. The article estimates that over 75,000 people in Wuhan had contracted the virus as of Jan. 25. It took 6.4 days for the epidemic to double in size.