Novel coronavirus pneumonia is caused by 2019-2019-nCoV coronavirus. Currently, the first identified case is from a seafood market, and the initial source of infection is wildlife, most likely Chinese chrysanthemum-headed bats.
So far, according to the “Diagnosis and Treatment Protocol for Novel Coronavirus Infection Pneumonia (Trial Version 4)”, the main source of infection is patients with pneumonia infected with novel coronavirus, and since the virus is transmitted mainly by respiratory droplet transmission and contact, close human-to-human contact can lead to infection with the virus.