Three suspected cases of Wuhan diseases were reportedly identified in Shenzhen and Shanghai after the Wuhan Health Commission announced to have 21 more confirmed cases in two days.

On Saturday early morning, the Wuhan Health Commission said it had identified 45 patients who were infected with the new coronavirus that could cause pneumonia. As of Thursday late evening, 15 people had recovered and left the hospital. Five people were in serious condition and two died.

The commission said the four new patients showed symptoms of pneumonia between January 5 and 8 and were admitted to hospital.

A total of 763 people who had close contact with the patients had been under medical observation while 665 of them had finished the observation period, the commission said, adding that it was following up with the two patients in Thailand and another in Japan.

On Sunday early morning, the commission said it had identified another 17 patients as of Friday late evening.

In Hong Kong, the Centre for Health Protection announced on Saturday that it identified seven more suspected cases of “Severe Respiratory Disease associated with a Novel Infectious Agent,” pushing up the total number of suspected cases to 90. Among the new cases, some were infected with influenza and adenovirus.

According to the South China Morning Post, at least two suspected cases had been reported in Shenzhen while another suspected case was identified in Shanghai. Citing unnamed sources, the Hong Kong-based newspaper said the two patients in Shenzhen were in quarantine at the Third People’s Hospital.

According to a recent paper published by the MRC Centre for Global Infectious Disease Analysis at Imperial College in London, the total number of infected patients with the unknown pneumonia disease could be as high as 1,700.

The researchers made the estimation by considering the fact that three confirmed cases had been reported in Thailand and Japan. The three overseas cases would imply that there would be many more cases than have been reported in Wuhan, Neil Ferguson, one of the authors of the report, told the BBC.

“People should be considering the possibility of substantial human-to-human transmission more seriously than they have so far,” Ferguson said.

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