Bird Flu 'Cluster' Found: Good News and Bad News

A family of eight was found infected with bird flu this week, prompting fears that the virus had mutated to allow human-to-human transmission leading to a pandemic.

However, experts told ABC News the event was not unequivocally a cause for alarm.

The Good News: -- Experts said this is not the start of a pandemic. If it were, there would be hundreds, maybe thousands of people sick by now.

"The first case(s) in this family cluster arose in late April, more than three weeks ago. If the virus that has affected this family had been a true pandemic virus, it would have spread throughout the neighborhood, into the community and into adjacent and even far-distant communities. The absence of such spread, together with the genetic sequencing data, clearly indicates that this virus is not the harbinger of the next pandemic," said David Fedson, infectious disease and vaccine expert, formerly of Sanofi-Pasteur.

-- The virus does NOT show signs of mutation. The World Health Organization has already tested samples from the 6 confirmed cases in the family and the virus looks like the same H5N1 virus that is circulating in birds. For the virus to become one that spreads to humans easily, it MUST mutate.

-- The "mother of all clusters" remark from the WHO Indonesian official is probably an overstatement. There have been other clusters approximately the same size.

Infectious disease expert Bill Schaffner of Vanderbilt University said of the remarks, "It's more excitable than if I were the official; I wouldn't say that. It's certainly a cluster."

The Bad News:

-- If these cases turn out to be human-to-human transmissions of bird flu, there is no pandemic yet, but it would be alarming. It would indicate the virus is picking up steam -- experts say it would mean virus is "one step closer" to pandemic.

What is the WHO doing now?

Dick Thompson, the WHO avian influenza media contact who is currently in Jakarta said:

-- WHO is backtracking from the first victim -- where did she become infected? Could other family members have become infected the same way?

-- WHO has found birds in the area that are carrying antibodies to the H5N1 virus, but not the virus itself. This means the virus is around and birds were exposed but apparently did not fall ill.

-- WHO has analyzed samples of the virus from all Indonesian family members but the 1st one, who was buried before testing. The virus does NOT show signs of mutating.

-- WHO is not yet ready to conclude "human to human" transmission until all other avenues (contact with sick birds, bird droppings, or other animals) have been eliminated.