OAKLAND (CBS SF) — A number of patients in Alameda County are being tested to see whether they have contracted the Wuhan coronavirus, according to health officials.

The Alameda County Health Department is looking into whether or not the virus may have already spread to the East Bay. Health officials confirm, several people have been tested for the virus, but none of them has come out positive at this point.

Dr. Erica Pan with the Alameda County Health Department told KPIX “We don’t have any confirmed cases; there are none in the Bay Area that we are aware of.”

The death toll from the virus has now jumped to 25 in China and has sickened hundreds of others. The health department said there are fewer than 10 cases being investigated in the East Bay, and only a few of them have had samples sent out for testing at the Center for Disease Control in Atlanta. Those patients are under home isolation but, Dr. Pan says, it’s highly unlikely any of them actually has the coronavirus.

Dr. Pan added, “We think it’s really low risk in the Bay Area but we are working together to detect early and contain it.”

SFO is one of five airports in the country screening people for the virus. Travelers from Wuhan who arrived before the quarantine was put into place were contacted and checked for any flu-like symptoms associated with the coronavirus.

ALSO READ: Passengers From Wuhan Halted From Flying To SFO Due To Coronavirus Outbreak

First identified last month, the novel virus has infected at least 830 people and has killed 25 people in China as of Thursday evening.

Health officials are looking into a possible case in Los Angeles and another in Texas involving a college student who had just returned from China.

ALSO READ: Coronavirus fact sheet (.pdf): English | Chinese

The first case of the Wuhan coronavirus in the U.S. was reported in Washington state. The CDC said the patient is a man in his 30s who lives north of Seattle and is now in a hospital in Everett, Washington.

The man returned to the Seattle area last week after traveling to Wuhan in central China, where the outbreak began.

NEW: @WHO declares new #coronavirus is *China* emergency but "still too early" to call it *global.*

-Now 830 China cases, up ~200 overnight

-25 dead in China, up 7

-*20 million people* in 5 cities on public transport lockdown@CBSNews @CBSThisMorning is here. Wash your hands!🖐 pic.twitter.com/rVs6RBr5Ty — Ramy Inocencio 英若明 (@RamyInocencio) January 24, 2020

The outbreak has prompted all passengers arriving from Wuhan to face additional screening at SFO, along with Los Angeles International Airport and John F. Kennedy International Airport in New York. About 150 passengers arrive on direct flights from Wuhan every Tuesday, Thursday and Saturday into San Francisco.

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.

© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. KPIX 5’s Andrea Nakano and the Associated Press contributed to this report