Family's Bird Flu Deaths Spark Worry

A family of eight infected with bird flu in Indonesia likely passed the disease among themselves, but the World Health Organization said Wednesday there is no reason to raise its pandemic alert level.

Six of seven people in the extended family in northern Sumatra have died, the most recent on Monday. An eighth person who died early this month was buried before tests could be conducted, but she was considered to be among those infected with the deadly H5N1 strain of bird flu.

It is the fourth — and largest — family cluster of bird flu cases likely transmitted from human to human since the start of the outbreak in Hong Kong in 2003, said Gregory Hartl, a spokesman for the Geneva-based WHO.

In the three previous family clusters — in Indonesia, Thailand and Vietnam — the number of infected relatives was much smaller, Hartl said.

The family members' close proximity is probably responsible for the spread of the disease, but that does not indicate the virus is mutating into a form that could cause a pandemic, Hartl said.

"It fits the kind of pattern perfectly which we've seen so far," Hartl said. "It still says that the virus hasn't mutated."

Dr. Anthony Fauci of the National Institutes of Health agrees. "The important point that we should emphasize to the public is that in examination of the virus itself, there doesn't appear to be any molecular or genetic changes or mutations as we call them that are associated with what we would consider a better transmissibility from human to human," he told CBS Evening News anchor Bob Schieffer.

Experts have feared that a mutation of the H5N1 virus into a strain that could easily pass among humans could set off a flu pandemic.

"When it spreads from human to human — if this is indeed the case here, and it's certainly something that we're looking at — it apparently can only spread between human to human when there is extensive and close contact between someone who is already showing clinical signs of the disease and the uninfected person," Hartl said.

The WHO's alert level remained at 3, the same level it has been at for months.

According to the agency's six-level pandemic alert system, Phase 3 indicates no human-to-human spread or only on rare occasions after close contact with a sick individual. Phase 4 means a small cluster or clusters of limited and localized human-to-human spread, a pattern suggesting the virus had not yet become fully efficient at infecting people. Phase 6 is a pandemic.

A Canadian infectious disease expert called the development in Indonesia "quite bothersome."

Dr. Donald Low, who runs Ontario's Public Health Laboratory in Toronto, noted it's a large family cluster of cases with a high death rate among victims who were very young to middle aged.

"But probably the most disconcerting," Low said, is evidence suggesting the virus had been transferred from one person to another, who became ill and passed the virus to yet another person. "That's what we refer to as a second-generation transmission, and we've never seen this before."

He said the WHO might have to consider raising the alert level to 4 in the coming days, although that hasn't happened yet. Maria Cheng, a WHO spokeswoman, said it was unlikely the agency would raise the alert level in the immediate future.

The WHO had considered convening a meeting of experts to debate whether to raise the alert level, but had decided that the current situation did not merit that step. "We had discussed that," she said. "But that is not going to happen."

The WHO has suspected that in rare cases, bird flu may have passed from one person to another, although people usually catch it from poultry. Experts have long believed the virus is spread when people breathe it in — possibly in dust from bird droppings or in droplets sneezed or coughed by humans into the air.

But it remains unclear how the virus spreads in family groups — whether through respiratory systems, food, infected surfaces or a combination, Hartl said. "When you get all of these things together, it becomes perhaps more likely."

Other experts have suggested family members have a genetic weakness to the disease. In all four family clusters recorded so far, only direct blood relatives — not spouses — have caught bird flu.

Health experts are trying to determine if the virus has spread outside the family. "That would be very worrying. We haven't seen any signs of that yet," said Peter Cordingley, spokesman for WHO's Western Pacific region.

Still the size of the cluster and the failure to determine the source of the infections was worrying, Cordingley said.

The WHO says 218 people have been confirmed to have been infected with bird flu since 2003, and 124 of them have died.

The agency said the Indonesian Health Ministry had confirmed a man who died May 22 had been infected with the H5N1 strain of bird flu.

He was the seventh member of an extended family confirmed to have become infected. An eighth person in the family, who died of similar symptoms May 4, was buried before tissue samples could be taken, so the cause of death could not be determined, but she is assumed to be part of the cluster, WHO said.

The family lives in the Kubu Sembelang village, Karo District, of North Sumatra.

"The newly confirmed case is a brother of the initial case," WHO said in a statement. "Tests run overnight confirmed his infection. His 10-year-old son died of H5N1 infection on 13 May. The father was closely involved in caring for his son, and this contact is considered a possible source of infection."

It said preliminary findings indicate that three of the confirmed cases spent the night of April 29 in a small room with the first infected woman and that she was coughing frequently.

That group included the woman's two sons and a second brother, who is the sole surviving case among infected members of this family, WHO said. Other infected family members lived in adjacent homes.