Mechanisms of arthropod transmission of plant and animal viruses

A majority of the plant-infecting viruses and many of the animal-infecting viruses are dependent upon arthropod vectors for transmission between hosts and/or as alternative hosts. The viruses have evolved specific association s with their vectors, and we are beginning to understand the underlying mec hanisms that regulate the vints transmission process. A majority of plant v iruses are carried on the cuticle lining of a vector's mouthparts or foregu t. This initially appeared to be simple mechanical contamination, but it is now known to be a biologically complex interaction between specific virus proteins and as yet unidentified vector cuticle-associated compounds. Numer ous other plant viruses and the majority of animal viruses are carried with in the body of the vector These viruses have evolved specific mechanisms to enable them to be transported through multiplet tissues and to evade vecto r defenses. In response, vector species have evolved so that not all indivi duals within a species are susceptible to virus infection or can serve as a competent vector. Not only are the virus components of the transmission pr ocess being identified, but also the genetic and physiological components o f the vectors which determine their ability to be used successfully by the virus are being elucidated. The mechanisms of arthropod-virus associations are many and complex, but common themes are beginning to emerge which may a llow the development of novel strategies to ultimately control epidemics ca used by arthropod-borne viruses.