Flu has long been a killer, and the 1918 outbreak killed approximately 40 million (spanish. The natural home of flu is in waterfowl and swine (e. g. ducks, geese, swans, pigs) All flu is spread by either birds or swine. Bird flu crisis began in 1997, when new bird flu strain (h5n1) was discovered in hong. H5n1 was a strand of flu that humans were not immune to and it was deadly. It was transmitted from bird to human but never from human to human. For it to go to human to human it would have to mix with a strand of the normal flu. Social commentator, who has written many books on the environment and la. Monster at our door wrote planet of slums . Millions of people in the world are living in shack settlements. There"s a social emergency about housing that hasn"t been explored enough. Tries to expose the social inequalities that drive disease and environmental destruction.