The role of molecular biology in veterinary parasitology

The tools of molecular biology are increasingly relevant to veterinary para sitology. The sequencing of the complete genomes of Caenorhabditis elegans and other helminths and protozoa is allowing great advances in studying the biology, and improving diagnosis and control of parasites. Unique DNA sequ ences provide very high levels of specificity for the diagnosis and identif ication of parasite species and strains, and PCR allows extremely high leve ls of sensitivity. New techniques, such as the use of uniquely designed mol ecular beacons and DNA microarrays will eventually allow rapid screening fo r specific parasite genotypes and assist in diagnostic and epidemiological studies of veterinary parasites. The ability to use genome data to clone an d sequence genes which when expressed will provide antigens for vaccine scr eening and receptors and enzymes for mechanism-based chemotherapy screening will increase our options for parasite control. In addition, DNA vaccines can have desirable characteristics, such as sustained stimulation of the ho st immune system compared with protein based vaccines. One of the greatest threats to parasite control has been the development of drug resistance in parasites. Our knowledge of the basis of drug resistance and our ability to monitor its development with highly sensitive and specific DNA-based assay s for 'resistance'-alleles will help maintain the effectiveness of existing antiparasitic drugs and provide hope that we can maintain control of paras itic disease outbreaks. (C) 2001 Published by Elsevier Science B.V.