Saliva: potential diagnostic value and transmission of 2019-nCoV

2019-n Co V epidemic was firstly reported at late December of 2019 and has caused a global outbreak of COVID-19 now. Saliva, a biofluid largely generated from salivary glands in oral cavity, has been reported 2019-n Co V nucleic acid positive. Besides lungs,salivary glands and tongue are possibly another hosts of 2019-n Co V due to expression of ACE2. Close contact or short-range transmission of infectious saliva droplets is a primary mode for 2019-n Co V to disseminate as claimed by WHO, while long-distance saliva aerosol transmission is highly environment dependent within indoor space with aerosol-generating procedures such as dental practice. So far, no direct evidence has been found that 2019-n Co V is vital in air flow for long time. Therefore, to prevent formation of infectious saliva droplets, to thoroughly disinfect indoor air and to block acquisition of saliva droplets could slow down2019-n Co V dissemination. This review summarizes diagnostic value of saliva for 2019-n Co V, possibly direct invasion into oral tissues, and close contact transmission of 2019-n Co V by saliva droplets, expecting to contribute to 2019-n Co V epidemic control.