Asteroid impacts, massive volcanic flows, and now biting, disease-carrying insects have been put forward as an important contributor to the demise of the dinosaurs. In the Late Cretaceous the world was covered with warm-temperate to tropical areas that swarmed with blood-sucking insects. A theory explored by researchers at Oregon State suggests these bugs carried leishmania, malaria, intestinal parasites, arboviruses and other pathogens. Repeated epidemics may have slowly-but-surely worn down dinosaur populations while ticks, mites, lice and biting flies tormented and weakened them. 'After many millions of years of evolution, mammals, birds and reptiles have evolved some resistance to these diseases,' says Researcher George Poinar. 'But back in the Cretaceous, these diseases were new and invasive, and vertebrates had little or no natural or acquired immunity to them.' The confluence of new insect-spread diseases, loss of traditional food sources, and competition for plants by insect pests could all have provided a lingering, debilitating condition that dinosaurs were ultimately unable to overcome

http://science.slashdot.org/article..../01/04/1558257