Study Confirms 2006 Human-Human Spread of Bird Flu

WASHINGTON (Reuters) Aug 29 - A mathematical analysis has confirmed that H5N1 avian influenza spread from person to person in Indonesia in April, U.S. researchers reported on Tuesday.
Dr. Ira Longini and colleagues at the Fred Hutchinson Cancer Research Center in Seattle looked at two clusters of human H5N1 infections -- one in which eight family members died in Sumatra in 2006, and another in Turkey in which eight people were infected and four died.
"We find statistical evidence of human-to-human transmission in Sumatra, but not in Turkey," the investigators write 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, 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," Dr. 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 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.