PCR as a diagnostic and quantitative technique in veterinary parasitology

Over the past 15 years, there has been a dramatic evolution in molecular ap proaches to study parasites and parasitic diseases. Many of these advanceme nts have been brought about through the development of new applications of the polymerase chain reaction (PCR). Enhancements in sensitivity that can b e achieved using PCR now permit scientists to investigate changes at the le vel of a single cell, far below what is often needed for parasite-derived a pplications. PCR has had a substantial impact on advances made in the areas of parasite systematics and epidemiology, immunology and host-parasite int eractions, recombinant DNA vaccine development and most recently, the analy sis of whole genomes either through directly sequencing the DNA, the analys is of expressed sequence tags (ESTs) or through the rapidly growing field o f functional genomics. This paper, however, focuses on the application of P CR methodology to parasite detection and differentiation, and the diagnosis of disease. Specific attention is given to advances provided by multiplex PCR, fluorescence-based "real-time" PCR, and the utilization of PCR as a qu antitative technique. Published by Elsevier Science B.V.