It can spread person to person, even if someone is showing no symptoms. The next in line can continue to pass it on. The incubation period is so long that people may not know where or when they picked it up.
Details that emerged last week about the new virus from China show how challenging it could be to control this outbreak, health experts say.
At first, some were relieved that the virus hasn’t proved fatal as often as those that caused SARS, Ebola or some other recent menaces. Now there’s worry that it still might cause a lot of deaths if it spreads far more than those other viruses did.
“The level of concern has been growing” with the new revelations about viral spread, said Marc Lipsitch of Harvard’s School of Public Health.
The virus has infected at least 14,000 people since it was first detected in central China in late December. It has killed more than 300 and spread to about two dozen countries although most, like the United States, have few cases.
“We still have a low risk to the American public, but we want to keep it at a low risk,” the National Institutes of Health’s infectious disease chief, Dr. Anthony Fauci, said Friday at a news conference where quarantines and temporary travel bans were announced.
Several factors about the virus itself affect how bad the outbreak might become.
Based on the first 425 confirmed cases in China, each infection led to 2.2 others on average, Chinese scientists reported last week in the New England Journal of Medicine. That’s a bit more than ordinary flu but less than SARS, a genetic cousin of the new virus.
“It sounds and looks as if it’s going to be a very highly transmissible virus,” said Robert Webster, an infectious disease expert at St. Jude Children’s Research Hospital who has studied many outbreaks.
Whether the new virus will weaken as it spreads or instead become better at it isn’t known.
“This virus may still be learning what it can do,” Webster said. “We don’t know its full potential yet.”
The biggest worry is sustained transmission, where one person spreads the virus to another and that person continues to pass it on. A related concern is how often people with no symptoms are infecting others.[ad_2]