Virulence and transmission of infectious diseases in humans and insects: evolutionary and demographic patterns

The rate and degree of proliferation of disease organisms determine their pathogenicity and the efficiency of their transmission. These traits dictate the impact of a disease on individuals as well as populations. Virulence and transmission of diseases are molded by evolutionary forces - pathogens and hosts are each selected to reproduce and persist. New ideas about the evolution of human diseases also apply to the relationships between insects and their diseases. Evidence for close associations between insects and pathogens include the viral suppression of insect molting hormones and the occurrence of latent virus that can be activated by foreign viruses.