A Hong Kong woman who recently visited Wuhan in China was placed in isolation in Tuen Mun Hospital on Tuesday, pending a test on whether she was infected with a mystery version of pneumonia.

According to the Hospital Authority, the woman suffered from fever and an upper respiratory tract infection. She showed negative results to tests for severe acute respiratory syndrome, influenza and avian influenza.

Media reports said the woman was aged about 30 and had a very sore throat. She said she had not been to any wet markets in Wuhan.

The woman’s fever was gone by Thursday, while X-rays showed her lungs were not infected, RTHK reported.

Another woman went to Tseung Kwan O Hospital on Thursday and said she had recently been to Wuhan, according to a source from the Hospital Authority.

She did not have a fever or any symptoms of pneumonia. She will stay in the hospital for further medical checks, while her case will not be sent to the Center for Health Protection.

The Wuhan Municipal Health Commission recently launched an investigation into a number of pneumonia cases related to a local seafood market – the Huanan Seafood Market. This was according to a statement by The Centre for Health Protection (CHP) of the Department of Health on Tuesday.

The commission has so far identified 27 cases and revealed that the cases were compatible with viral pneumonia. Among them, seven cases were serious and the remaining patients were stable.

The symptoms were mainly fever, while a few patients had shortness of breath. All were isolated and receiving treatment. Contact tracing of close contacts and medical surveillance were ongoing.

For the time being, no obvious human-to-human transmission had been observed and no healthcare workers had been infected, the commission said. The cause of infections was under investigation.

All the patients infected by the unknown virus had been sent to Wuhan Jinyintan Hospital, a medical institution for infectious diseases, The Beijing News reported.

Some stores in the Huanan Seafood Market were selling cats, dogs, snakes and other wild animals, which were more likely to be carriers of the unknown virus than seafood, the Hubei Daily reported.

A tourist arriving in Hong Kong from Wuhan told RTHK that local people had received short mobile messages from the Wuhan government about the reported diseases.

She said Wuhan people were not in a panic and did not take a lot of protective measures as they believed the epidemic had been contained.

Roy Tam Hoi-pong, a Tsuen Wan district councilor and an environmental activist, said the two high-speed trains arriving in Hong Kong from Wuhan every day should be suspended immediately. Tam said the Hong Kong government and MTR Corp should explain to Hong Kong citizens how they were going to prevent the spread of the unknown virus on the high-speed trains.