Hong Kong's Department of Health (DH) Wednesday announced a new case of human infected with H7N9 as a 75-year-old man died Wednesday morning in the hospital.

The man is also the fourth confirmed case of human infected with H7N9 bird flu in Hong Kong.

The Center for Health Protection (CHP) of DH said, the patient, with multiple underlying illnesses, developed cough with sputum in Shenzhen on Jan. 26 and attended the Accident and Emergency Department of Tuen Mun Hospital (TMH) on Tuesday evening for fever and shortness of breath. The man was subsequently transferred to the isolation ward but died Wednesday morning after his condition deteriorated.

According to the CHP, the patient's nasopharyngeal aspirate was positive for avian influenza A (H7) virus upon preliminary laboratory testing and was confirmed as H7N9 upon further testing.

Initial investigations by the CHP revealed that the patient had traveled alone to Shenzhen, Guandong Province, from Jan. 20 to 26 and had stayed in his relative's home close to a live poultry market.

The patient's five family members in Hong Kong who have been regarded as close contacts have remained asymptomatic so far. They will be admitted to Princess Margaret Hospital for testing and observation, according to DH.

Further investigations into his travel and exposure history are ongoing, the CHP said, adding tracing of other contacts of the patient is also under way, including four patients who stayed in the same cubicle with the patient in TMH, healthcare workers of TMH and the ambulance service, who will be put under medical surveillance.

The CHP will liaise with relevant mainland health authority to follow-up the patient's contacts during his stay in Shenzhen.

"The Serious Response Level under the Government's Preparedness Plan for Influenza Pandemic remains activated and the CHP's follow- up actions are in full swing," a spokesman for the DH remarked.

The CHP will notify the World Health Organization (WHO), the National Health and Family Planning Commission as well as health and quarantine authorities of Guangdong and Macao.

On Dec. 26, 2013, an 80-year-old man died of H7N9, who was the first dead case since Hong Kong found human infected with H7N9 bird flu on Dec. 2, 2013.

Hong Kong Tuesday culled 20,000 live poultry after the sample of imported poultry from Guangdong was found carrying the virus. The government has decided to suspend poultry import from the mainland and live poultry sales on local markets for at least three weeks.