Human-to-Human Transmission of H5N1 Confirmed

Posted on August 28, 2007

Reuters reports that matematical analysis has confirmed that the deadly bird flu virus was spread from human to human in Indonesia in 2006.

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. Photo
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.

The human-to-human transfer of bird flu is suspected in cases from Sumatra where a 10-year-old boy caught the virus from his 37-year-old aunt and then spread the virus to his father. The outbreak in Sumatra was stopped before the virus could spread outside of the family.

The cluster contained a chain of infection that involved a 10-year-old boy who probably caught the virus from his 37-year-old aunt, who had been exposed to dead poultry and chicken feces, the presumed source of infection. The boy then probably passed the virus to his father. The possibility that the boy infected his father was supported by genetic sequencing data. Other person-to-person transmissions in the cluster are backed up with statistical data. All but one of the flu victims died, and all had had sustained close contact with other ill family members prior to getting sick -- a factor considered crucial for transmission of this particular flu strain.
In an attempt to contain the spread of the virus, the local health authorities eventually placed more than 50 surviving relatives and close contacts under voluntary quarantine and all, except for pregnant women and infants, received antiviral medication as a precaution.
"The containment strategy was implemented late in the game, so it could have been just luck that the virus burned out," Longini said. "It went two generations and then just stopped, but it could have gotten out of control. The world really may have dodged a bullet with that one, and the next time we might not be so lucky," he said.

Now we know that H5N1 can be transmitted from person to person. Fortunately, the h2h transmission is not easy and does not appear to happen quickly. If the virus mutates and acquires the ability to easily transfer among humans then the possibility of global pandemic becomes much more likely.

H5N1