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.
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
“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.