SAN FRANCISCO (CBS SF) — Federal health officials will begin screening ill passengers on flights coming into San Francisco International Airport from China for any signs of a deadly new virus that has already claimed two lives in Wuhan and spread to Thailand and Japan.

The Centers for Disease Control and Prevention and the Department of Homeland Security’s Customs and Border Protection said any passenger who arrives from a flight from China will immediately undergo entry screening for symptoms associated with the Novel Coronavirus.

The screenings will also be enforced at Los Angeles International and New York’s John F. Kennedy Airport. The CDC said it was deploying about 100 additional staff to the three airports to supplement existing staff at the quarantine stations located at those airports.

“To further protect the health of the American public during the emergence of this novel coronavirus, CDC is beginning entry screening at three ports of entry,” said Martin Cetron, M.D., Director of CDC’s Division of Global Migration and Quarantine. “Investigations into this novel coronavirus are ongoing and we are monitoring and responding to this evolving situation.”

Health officials said the current risk to the American public is “deemed to be low.” But the screenings are a proactive precaution.

“Entry screening alone is not a guarantee against the possible importation of this new virus but is an important public health tool during periods of uncertainty and part of a multilayered government response strategy,” federal health officials said in a release.

Dr. William Schaffner, an infectious disease specialist from Vanderbilt, says passengers will have to fill out a questionnaire and have their temperature taken. Both SARS and MERS were forms of Corona virus.

“That’s capable of causing serious lung disease. It’s sickened over 40 people so far, two of whom have died,” Dr. Schaffner told KPIX5 via Skype.

How dangerous the virus is still a mystery to scientists.

“We don’t really know yet whether this virus can spread from person to person. We think it may have happened a couple of times already,” explained Dr. Schaffner. “So, we don’t want people coming into this country suddenly spreading it to people in their homes or at work — wherever they’re going.”

Dr. Schaffner says the screening process will be complicated for one more reason.

“You and I know we’re in the middle of influenza season. So, flu can give you a little bit of a fever,” said Dr. Schaffner. “So nobody know yet how many people are going to be asked to step aside for further examination.”

There are three direct flights a week aboard China Southern Airlines from Wuhan to SFO each with 150 passengers. SFO spokesperson Doug Yakel says about 10-25 other passengers a day will arrive in SFO from Wuhan via other connections.

“They’re going to begin screening passengers arriving from Wuhan, China beginning this evening,” said Yakel.

The first flight under the new screening protocol will land at JFK in New York Friday evening. SFO will see it’s first flight Saturday at 1 p.m. from Wuhan.

China health officials report that most of the patients infected with Novel Coronavirus have had exposure to a large market where live animals were present, suggesting the virus has jumped the species barrier to infect people.

The Chinese government is keen to avoid a repeat of SARS, or severe acute respiratory syndrome. The SARS epidemic began in southern China in late 2002, then spread to more than two dozen countries, killing nearly 800 people.

Chinese health official said 41 people in Wuhan have been diagnosed with a novel coronavirus, a family of viruses that can cause both the common cold and more severe diseases like SARS and MERS. As of late Thursday, 12 patients have been cured and discharged and five were being treated for acute conditions and two have died.

Most of the coronavirus patients this time either worked at or visited a particular seafood market in Wuhan. The market has since been shut down for investigation and disinfection.

Two patients in Thailand and another in Japan have been diagnosed with the virus.

A 74-year-old tourist was intercepted at a Thai airport on Jan. 13 with symptoms of lung infection, the country’s public health ministry said Friday. She is being treated in the same hospital, east of Bangkok, as a Chinese woman who was diagnosed with the virus after entering the country last week.

The Chinese woman is getting better and will soon be released, said Sukhum Kanchanapimai, Thailand’s permanent secretary for public health.

Japan’s health ministry said Thursday the virus had been confirmed in a man who had been hospitalized in Japan with pneumonia symptoms after traveling to Wuhan earlier this month. His condition has improved. Kyodo News agency reported the man is Chinese.

Andria Borba contributed to this story.