Everything you need to know about coronavirus, the deadly illness alarming the world (Ⅱ)
When did the outbreak start? Where did coronavirus come from?
According to Chinese officials, 2019-nCoV first appeared Dec. 12 about 700 miles south of Beijing in Wuhan, a city with more people than New York and Chicago combined. Health officials say the outbreak originated at the Huanan Seafood Market.
Huanan Seafood, closed by officials on Jan. 1, was a wet market, one of a series of outdoor stalls(1) selling fish and meat, some of it from wildlife. They are called wet markets because sellers slaughter(2) and cut up animals and fish while customers wait.
The market is suspected because coronaviruses transmit zoonotic(3) diseases, meaning they are transferred from infected animals to humans.
Researchers theorize that someone bought contaminated(4) meat at the market, ate it, got sick and infected others, creating a ripple effect(5) around the world.
What are the symptoms of coronavirus?
Common signs of infection include fever, cough, shortness of breath and breathing difficulties. Experts are unsure of whether the virus is able to transmit before symptoms appear or after. If it worsens, it can cause pneumonia(6), severe acute respiratory syndrome, kidney failure or even death.
The virus can be spread from animals to people. But it also can be spread by coughing, sneezing and through close contact with an infected person or an object carrying the virus. Experts are still figuring out how long an infected person is contagious(7) as they try to determine a point of transmission.(8)
The coronavirus when viewed microscopically(9) has spikes(10) that adorn(11) the outer surface of the virus, which impart(12) the look of a crown.
Coronaviruses are named after their appearance, round with a series of spikes made of proteins, resulting in a crown-like look. They're one of many viruses that cause colds and flu.
A new, evolved version, such as 2019-nCov, can cause more serious illnesses, some of which can be deadly to older people or those with weakened immune systems.
Coronaviruses are found in a variety of animals. If passed from animal to human, the virus can change and infect other humans, who can spread the infection to others, according to the CDC.
Lord said that bats' evolution has made them become carriers of these diseases without actually getting sick. She thinks they pass around these viruses to each other because they live in such large colonies in relatively small quarters(13).
Humans are partly to blame for outbreaks as development encroaches(14) on bats' natural habitats, Lord said. Taking care of the environment to contain bats and keeping live markets clean are two ways humans can work to prevent outbreaks.
"The health of environment, the health of animals and the health of humans are all related," she said. "We have to think about the whole big picture, we have to protect everything."
a ripple effect：连锁反应
Coronaviruses are named after their appearance, round with a series of spikes made of proteins, resulting in a crown-like look.