Study confirms 2006 human-human spread of bird flu
Tue Aug 28, 2007 11:37PM BST

WASHINGTON (Reuters) - A mathematical analysis has confirmed that H5N1 avian influenza spread from person to person in Indonesia in April, U.S. researchers reported on Tuesday.

They said they had developed a tool to run quick tests on disease outbreaks to see if dangerous epidemics or pandemics may be developing.

Health officials around the world agree that a pandemic of influenza is overdue, and they are most worried by the H5N1 strain of avian influenza that has been spreading through flocks from Asia to Africa.

It rarely passes to humans, but since 2003 it has infected 322 people and killed 195 of them.

Most have been infected directly by birds. But a few clusters of cases have been seen and officials worry most about the possibility that the virus has acquired the ability to pass easily and directly from one person to another. That would spark a pandemic.

Ira Longini and colleagues at the Fred Hutchinson Cancer Research Center in Seattle looked at two clusters -- one in which eight family members died in Sumatra in 2006, and another in Turkey in which eight people were infected and four died.

Experts were almost certain the Sumatra case was human-to-human transmission, but were eager to see more proof.

"We find statistical evidence of human-to-human transmission in Sumatra, but not in Turkey," they wrote in a report published in the journal Emerging Infectious Diseases.

"This does not mean that no low-level human-to-human spread occurred in this outbreak, only that we lack statistical evidence of such spread."

In Sumatra, one of Indonesia's islands, a 37-year-old woman appears to have infected her 10-year-old nephew, who infected his father. DNA tests confirmed that the strain the father died of was very similar to the virus found in the boy's body.

"It went two generations and then just stopped, but it could have gotten out of control," Longini said in a statement.

"The world really may have dodged a bullet with that one, and the next time, we might not be so lucky," he added.

The researchers estimated the secondary-attack rate, which is the risk that one person will infect another, was 20 percent. This is similar to what is seen for regular, seasonal influenza A in the United States.

The researchers developed a software product called TranStat and said they would provide it free of charge on the National Institutes of Health's Models of Infectious Disease Agent Study, or MIDAS, Web site.

"We know the key to preventing a pandemic is early detection, containment and mitigation with antiviral therapy and this tool will enable those on the front lines, such as physicians, epidemiologists and other public-health officials, to carry that out efficiently," said Elizabeth Halloran, who worked on the study.

Personally, I have a friend in the CDC who admitted off the record to human to human spreading about 10 months ago. They aren't keen to admit it (so they haven't yet) as it means we are possibly only a few mutations away from something that could be like Captain trips. While tracking bird flu cases they found it wasn't following normal migration patterns. They looked into it and discovered human to human cases and transport patterns.

Although, my friend did say that a highly contagious, highly fatale virus is astonishingly rare. The most likely mutation would do something like a normal flu. As the human to human spread article is out there I'm comfortable putting this out in the public domain (at least on this forum).

That news was enough for my normally relaxed father to stock up on food and water to avoid having to go to the grocery/public areas.

Myself, I'm not too worried about it. I suspect that if anything is released within the next 3 years it will be an engineered virus (to blame the economic crash on). That is just a guess though (based on current global trends to sacrifice one's own people).

Exercise, eat well, stay healthy and most of all savor every day!

-NIM

Not really news. The scientific community has been "pretty sure" that human-to-human transmission has been happening since clusters in Vietnam and Indonesia in 2004. They key difference between whether this is a contained problem and a full-blown epidemic/pandemic is not whether human-to-human transmission has occurred (it likely already has) but whether the transmission occurs quickly and efficiently among people. So far, H5N1 hasn't demonstrated that yet (thankfully).

..."statistical evidence"... ?

Sue

Yes, this medical article is based on the results of a mathematical model based on various variables. It's kind of like the projections you see on the news these days about the estimated path of a hurricane, except in this case, the model is looking backwards in time, to estimate the probability that the avian flu was passed human-to-human versus gettting infected some other way. The hurricane mathmetical model has variables like ocean temperature, air temperature, direction of prevailing winds, etc. This avian flu model has things like duration of the overall outbreak, time between infections, the size of the households, how often their paths cross, demographic info, etc.

Well, that's a relief.


Frank2135