Chinese authorities reported four new H7N9 avian influenza infections in east China on Tuesday, bringing the total to 28 cases nationwide.

A 62-year-old man in Shanghai was hospitalized with a fever on April 1, the Shanghai Municipal Health and Family Planning Commission said in a statement.

The man, surnamed Lin, was later diagnosed with pneumonia. It was confirmed that he was infected with the H7N9 virus, a newly discovered strain of bird flu, late Monday night, according to the commission.

Another infection in Shanghai was confirmed early Tuesday morning, according to the statement.

The 77-year-old retiree, surnamed Wang, experienced fever and muscle pain on April 3. He was initially diagnosed with a respiratory infection and later diagnosed with pneumonia.

Both patients are currently in stable condition and receiving medical treatment, the statement said, noting that 10 people who have had close contact with them have not shown any abnormal symptoms.

As of 5 p.m. Tuesday, 13 cases of H7N9 infections had been confirmed in Shanghai, including five cases that ended in death, the statement said.

In neighboring Zhejiang Province, two new cases of H7N9 avian influenza were also reported Tuesday.

On Tuesday, H7N9 infections were confirmed in a 51-year-old woman, surnamed Jia, and a 79-year-old man, surnamed Tu, the Zhejiang provincial health department said in a statement.

Jia is currently in stable condition, while Tu is in critical condition, the statement said.

As of 4 p.m. Tuesday, five cases of the infection had been reported in Zhejiang, including two that have resulted in death, according to the statement.

Eight cases in Jiangsu Province and two in Anhui Province had also been reported as of 6 p.m. Monday.

Of the eight patients infected with H7N9 in Jiangsu, one died on Tuesday, bringing the total fatalities across the country to eight.

Despite medical efforts, the patient, an 83-year-old man surnamed Shen, died in the hospital on Tuesday afternoon, according to a statement issued by the provincial health department.

Shen, a native of Suzhou City, went to a local hospital on March 20 with flu-like symptoms. On April 2, it was confirmed that he was infected with the H7N9 virus.