https://www.the-scientist.com/news-opinion/scientists-zero-in-on-the-novel-coronavirus-incubation-period--67045 >>**To cause an infection**, a virus must invade cells and begin replicating. How quickly the virus spreads throughout the body depends on the virus’ lifecycle. “For SARS, that’s less than 24 hours: the virus particle could affect the cell and then emit thousands of progeny less than a day later,” says Tim Sheahan, an epidemiologist at the University of North Carolina at Chapel Hill who studied the SARS outbreak of 2003. “And that’s how the virus [is] capable of exponential growth.” Eventually, **the virus rearranges the cell’s membrane and prompts several cells to fuse together**. This causes enough damage to host tissues to tip off the immune system, triggering a response that causes symptoms as patients begin fighting off the infection. >>Coronaviruses such as those that cause SARS and Middle East respiratory syndrome (MERS) are **particularly adept at evading immune detection and dampening immune responses.** This partly explains why they tend to have longer incubation periods—two to seven days on average, but lasting up to two weeks—than infections such as influenza, which has an incubation period of just one to four days. **It’s not yet clear exactly how the 2019-nCoV affects the immune system.** https://pic8.co/sh/r9k8IT.jpeg ... https://www.webmd.com/lung/coronavirus#1 >>**A coronavirus is a kind of common virus that causes an infection in your nose, sinuses, or upper throat. Most coronaviruses are not dangerous.** Some types of coronaviruses are serious, though. About 858 people have died from Middle East respiratory syndrome (MERS), which first appeared in 2012 in Saudi Arabia and then in other countries in the Middle East, Africa, Asia, and Europe. In April 2014, the first American was hospitalized for MERS in Indiana and another case was reported in Florida. Both had just returned from Saudi Arabia. In May 2015, there was an outbreak of MERS in Korea, which was the largest outbreak outside of the Arabian Peninsula. In 2003, 774 people died from a severe acute respiratory syndrome (SARS) outbreak. As of 2015, there were no further reports of cases of SARS. But In early 2020, following a December 2019 outbreak in China, the World Health Organization identified **a new type**, 2019 novel coronavirus (2019-nCoV). >>What Is a Coronavirus? Coronaviruses were first identified in the 1960s, but **we don't know where they come from**. They get their name from their crown-like shape. Sometimes, but not often, a coronavirus can infect both animals and humans. **Most coronaviruses spread the same way** other cold-causing viruses do: **through infected people coughing and sneezing, by touching an infected person's hands or face, or by touching things such as doorknobs that infected people have touched.** Almost everyone gets a coronavirus infection at least once in their life, most likely as a young child. In the United States, coronaviruses are more common in the fall and winter, but anyone can come down with a coronavirus infection at any time.