In the 1940s to 1950s physicians noticed pesticide spraying overlapped with summer paralysis outbreaks.  It was then realized that this wasn't just a virus. Jim West later blew the whistle.  Suzanne Humphries and others then published graphs of DDT production versus polio cases further strengthening the correlation.  

As always, do your research.  I will let you decide.  Was it DDT or something else?  Thoughts? 

Much Love, Lynn