MOLECULAR EPIDEMIOLOGY - ASSUMPTIONS AND LIMITATIONS OF COMMONLY APPLIED METHODS

An understanding of the epidemiology of a disease (i.e. its aetiology, transmission patterns) is crucial for the development and implementat ion of effective management practices. This requires sound epidemiolog ical data. It is therefore important that scientists understand the as sumptions and limitations of the methods used to gather such data. The aim of this paper is to discuss some of the assumptions and limitatio ns of PCR-based methods used in studies of epidemiology. Since its dev elopment, PCR has had a major impact in the biological sciences. The a bility to selectively amplify a specific region of the genome from a s mall amount of DNA makes this technique particularly useful as a diagn ostic tool. A variety of PCR-based methods are available which can be used to identify strains and species of parasites. Some of these metho ds, such as random amplification of polymorphic DNA, have intrinsic pr operties which can limit their application. Other methods, such as PCR -restriction fragment length polymorphism, require the availability of a sound taxonomic or genetic framework for the development of any dia gnostic system for a particular organism. The problems encountered dev eloping diagnostic probes in the absence of such a framework will be d iscussed using Giardia intestinalis as an example. (C) 1998 Australian Society for Parasitology. Published by Elsevier Science Ltd.