The latest on the list of threatened species is the Guinea worm, or dracunculiasis. It is a parasite feasting on the smorgasbord also known as the human body.
The prestigious medical journal New England Journal of Medicine reports that this worm has almost been eradicated by introducing a longterm educational campaign.
20 years of campaigning reduced an incidence of this infection of 3,5 million to just 25,000 cases.
The larvae of this worm live in the water and enter the human body where they grow into worms that can be more than half a meter long. After a year the worms start crawling out of the skin which is apparently excruciatingly painful.
See here for a picture of the worm emerging - warning, it is not a nice picture.
http://content.nejm.org/content/vol356/issue25/images/large/01f2.jpeg
However, simple changes in behavioural patterns of humans can prevent infection and the campaign focussed on this.
And now the worm is almost gone. Since this poor thing doesn't have any other hosts it is doomed for extinction similar to smallpox.
The whole 20 year campaign was funded with merely 225 million dollars. That's about the same as the upkeep of Paris Hilton.
http://content.nejm.org/cgi/content/full/356/25/2561