Control of disease transmissson through genetic modification of mosquitoes

Vector-borne diseases remain one of the greatest menaces to humans throughout the world. Millions of people die every year from diseases such as malaria. and many more axe incapacitate of infections by a variety of vector-borne viral, protoroar,. and rmtazoar? pathogens. The exploitation of molecular bioiogica! techniques for research on zrthropod sectors of disease has fostered the development of novel disease-control strategies based on attacking the vector. One strategy pr to modulate vector competence geneticallq, reducing it to the point that it interrupts pa transmission (Collins and James. 1996: Jams et al., 1999). Vector competence as used here refers to the ability of an arthropod to serve as a suitable host for the transmissi and propagation of a pathogen. We refer specifically to properties that result from the genetic ckground of the host arthropod, and therefore this is a more limited definition of vector compe ce than that provided originally by Hardy et al. (1983). The hypothesis of this strategy is that the introduction into a vector population of a gene that confers resistance to a pathogen will result in a trailsmission of that pathogen. To test this hypothesis, a gene or allele that interferes wi ropagation must be spread through a vector population. Once the gene or allele iently abundant, measurable decreases in transmission and disease should be observed. Traransgenesis technology plays an important role in the development and implementation of this strategy and is absolutely necessary for practical experiments that will test the hypothesis. This chapter highlights current research efforts to use transgenic technology to produce parasiteresistant mosquitoes. osquitoes are vectors of major diseases and most of the recent developments in vector transgeilesis have taken place with them. The general background and research areas will be summarized, and this will be followed by a discussion of potentid targets and molecular strategies for intervention.