Swine flu developed within industrially grown herds of thousands of pigs in unsanitary conditions, which is a formula for creating the chance of a disease breakout.
The unintended consequence of the use of pigs kept in small numbers by families who collected and recycled garbage for income? A safer Cairo?
Why'd they really do it? They have had 30+ deaths from avian flu arising from "farming" too many chickens in unsanitary conditions for the world poultry market. Had to look good at something but not threaten the income of poultry traders. Add to this that the garbage pickers are minority Coptic Christians and the government probably thought no one would care.
But now the garbage is piling up
Swine-Flu Slaughter Leaves Cairo Without Pigs to Devour Trash