SEATTLE – Local researchers have now proven that bird flu has finally mutated and can be transmitted from person to person.  The outbreak occurred in 2006 in Indonesia.

Experts at Fred Hutchinson Cancer Research center in Seattle used statistical analysis and a computerized disease-transmission model to show the disease spread between a small number of people in one family.

The chain of infection involved a 10-year-old boy who likely caught the virus from his 37-year-old aunt who had been exposed to dead poultry and chicken feces.

Researchers say the boy then probably passed the virus to his father.

All but one of the flu victims died.  All of those who contracted the disease had long, close contact with other ill family members prior to getting sick.

Health authorities eventually placed more than 50 surviving relatives and close contacts under quarantine in an attempt to contain the spread. 

One of the authors of the study says that containment came late, so it was lucky the virus didn't spread any further.

"It went two generations and then just stopped, but it could have gotten out of control," said biostatistician Ira Longini, co-author of the study. "The world really may have dodged a bullet with that one, and the next time we might not be so lucky."

Longini says that if bird flu develops enough to cause sustained human-to-human contact, it could spread worldwide fast, before enough vaccine could be made available.

The researchers estimate the rate of one infected person passing bird flu to another in Indonesia is 29 percent.  That's similar to the spread of seasonal flu in the United States.

Researchers also say another bird flu case in eastern Turkey in 2006 that killed four people was probably spread person-to-person, but there wasn't enough statistical data to support the theory.

The study will be published Sept. 1 in Emerging Infectious Diseases, a journal of the Centers for Disease Control and Prevention.