Control of parasitic disease using vaccines: an answer to drug resistance?

Antiparasitic drugs have been used successfully to control parasitic diseases in animals for many years, as they are safe, cheap and effective against a broad spectrum of parasites. One drawback of this success appears to be the emergence of drug resistance in many target parasites. Moreover, issues of residues in the food chain and environment have arisen, which threaten their sustained use. Control methods in which vaccines would have a central role provide attractive alternatives. However, while attenuated parasite vaccines have been successful, sub-unit vaccines are still rare. The advent of new techniques in molecular biology allows the elucidation of entire parasite genomes and the identification of individual genes. It is envisaged that a further understanding of parasite genes and the role of their products in parasite biology may lead to the identification of useful antigens, which could then be produced in recombinant systems. However, for this aim to be realised, continued investment in basic research on the complex interplay between parasite and host will be necessary.