Pathogen evolution issues in genetically modified mosquito vector strategies

Abstract

In this paper, pathogen evolution will not be considered in the extended concept of adaptation through mutability, heredity and long-term adaptation through speciation. In contrast, the main issues deal with aspects related to polymorphism and population diversity that arise by selection processes and how these may influence vector– pathogen–human relationships. Three aspects related to these relationships will be presented in order to discuss the possibility that a reduction of the vector capability to transmit malaria could result in the selection of parasites. First, aspects of population size and diversity of Plasmodium (with emphasis on P. falciparum) relevant to epidemiology and host interactions will be presented. Next, Plasmodium–vector molecular interactions, determinant of infectivity, will be reviewed; these could determine the efficacy of a trait introduced by the genetic modification of the mosquito and/or could result in selection of parasites resistant to the trait. Finally, the possibility of virulence shifts in pathogens as a result of the genetically introduced traits in mosquitoes will be discussed