Some people may be genetically disposed to AI

This line of thought could explain why, given the same level of exposure, some people get bird flu and some people don’t – and may also explain why it is still relatively rare.

Evidence from a cluster bird flu case in Sumatra in Indonesia showed that genetic factors might influence susceptibility to the H5N1 virus.

Only blood relatives were infected in the Karo district of North Sumatra, the largest cluster known to date worldwide, in spite of the fact that the virus had multiple opportunities to spread to non-blood relations or the general community.

“A genetic predisposition for infection is suspected based on data from rare instances of human-to-human transmission in genetically-related persons,” the WHO said.

The theory was contained in a WHO report “Influenza Research at the human and animal interface”, issued on Thursday, on a closed-door meeting of 35 scientific experts held in late September.

“This possibility, if more fully explored, might help explain why human cases are comparatively rare and why the virus is not spreading easily from animals to humans or from human to human,” it added.