I think that environmental factors contribute to alot of health issues. Toxins are everywhere, and appropriate studies have not been done to see how dangerous they really are. Why waste millions of taxpayer dollars (if the cause isn't viral in nature) when a low expenditure to determine environmental factors could save lives.
So you're saying that it is all a eeeeevil corporate Republican vast right-wing conspiracy? Now, if it were environmental, explain how birds are dropping dead with West Nile in La Crosse, Wisconsin (where MTBE and ozone have never been an issue), and not in Los Angeles (where air quality was so bad that the word smog was essentially invented). Also, explain why nothing was happening anywhere until 1999, or why New York City first (and still not LA).
A more-logical explanation is the relatively-anitseptic nature of most of the items in modern American life, especially with the chil'run. With the relatively-harmless bacteria being systematically wiped out with various antibiotics (especially soaps, which came on the market in the late '90s), that leaves the much-harder-to-kill viruses (and those bacteria that survive the urge to purge) to attack an immune system not stimulated by the presence of the harmless stuff.