HONG KONG, China -- Hong Kong is on alert after a second case of the potentially deadly bird flu virus was confirmed. 

Hong Kong residents became nervous after a nine-year-old boy caught the virus after a visit to southeastern China. 

Reports also surfaced that the boy's father and sister had recently died from pneumonia. 

The Hong Kong government released a statement Thu rsday evening confirming the boy's father had died from the bird virus. 

This is the second time the disease has jumped from birds to humans since six people died in the territory in 1997. 

"Obviously, we are very concerned about the situation," the Secretary for Health, Welfare and Food, Dr Yeoh Eng-kiong, said in a statement earlier Thursday. 

"We know that avian flu is endemic in this part of the world and we have been looking at how we should be able to control it." 

Health officials say the bird flu strain infecting the boy is not the same as the one that killed six people in 1997. 

And they also say there's no evidence so far that this latest strain can be contracted through humans. 

Family deaths

The boy's eight-year-old sister fell ill in China and died in a hospital there on February 4. His father, 33, fell ill in China on February 7 and died 10 days later in a Hong Kong hospital. 

The family had just returned from a visit to Fujian in southeastern China, where five people died and hundreds fell ill from a rare form of pneumonia recently. 

The boy developed fever, cough and runny nose on February 7 and returned to Hong Kong, where he was admitted to a local hospital and is in a stable condition. 

Hong Kong authorities say they are working with mainland officials to monitor the situation. 

They have advised people living in the city to avoid direct contact with poultry and birds. 

While experts did not determine how the 1997 strain jumped from birds to humans, they ruled out the possibility the virus could be contracted by eating infected birds. 

Hong Kong health officials said they were testing everyone with severe pneumonia for the virus but had found no other positive results. 

The World Health Organization said it had alerted its global influenza surveillance network. 

The congested territory of 6.8 million people has been hit by three major bird flu outbreaks in the last five years, each time leading to massive culls.