London (CNN) The number of cases in an outbreak of a new strain of coronavirus in China is likely to have been grossly underestimated, according to a new study, which warns that human-to-human transmission of the mysterious virus may be possible.

Authorities in China's Wuhan city have confirmed 45 cases of the 2019 novel coronavirus, which is in the same family as the deadly severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), but so far appears to be less lethal. Two people have died, Wuhan authorities say.

But the study, by Imperial College London, suggests that an estimated 1,723 people were likely to have been infected by January 12.

Officials in China have linked the viral infections to a Wuhan seafood and wildlife market, which has been closed since January 1 to prevent further spread of the illness.

Members of staff of the Wuhan Hygiene Emergency Response Team conduct searches on the closed Huanan Seafood Wholesale Market in Wuhan.

Three travelers -- two now in Thailand and one in Japan -- who visited Wuhan but not the market have been infected with the virus, suggesting human-to-human transmission may be possible and raising concerns of the virus's further spread.

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