US to screen passengers for China mystery virus

US authorities will begin screening passengers Friday arriving on direct or connecting flights from a Chinese city at the heart of a mysterious SARS-like virus responsible for two deaths.

Travellers from Wuhan to the United States will undergo entry screening for symptoms associated with the new coronavirus at three airports: San Francisco, New York's JFK and Los Angeles.

China has now reported 45 cases linked to the virus, Centres for Disease Control and Prevention (CDC) official Nancy Messonnier told reporters in a press call, most linked to a seafood and live animal market in Wuhan, while two cases have been found in Thailand and one in Japan.

The CDC said that based on current information, the risk to Americans from the virus, known by its technical name 2019-nCoV, is currently deemed low. Nevertheless it was enhancing precautionary measures.

The CDC will deploy 100 additional staff to the three airports, with incoming passengers asked to fill out a questionnaire and submit to a temperature check.

Those who show possible signs will be shifted to another facility for additional screening and a rapid diagnostic test.

Messonnier said that this test would currently take around a day, "but it's going to get rapidly faster" as the diagnostic tool improves.

The UN's health agency says that the outbreak of the disease comes from a never-before-seen strain belonging to a broad family of viruses ranging from the common cold to more serious illnesses such as SARS.

According to Arnaud Fontanet, head of Paris' Institut Pasteur department of epidemiology, the new strain is the seventh known type of coronavirus that humans can contract.

The outbreak has caused alarm because of the link with SARS (Severe Acute Respiratory Syndrome), which killed 349 people in mainland China and another 299 in Hong Kong in 2002-2003.

Fontanet added that the coronavirus appears to be "weaker" than SARS in its current form, but cautioned that it could mutate into a more virulent strain.