Variation in Cryptosporidium: towards a taxonomic revision of the genus

Cryptosporidium is an important cause of enteric disease in humans and othe r animals. Limitations associated with conventional diagnostic methods for cryptosporidiosis based on morphological features, coupled with the difficu lty of characterising parasites isolated in the laboratory, have restricted our ability to clearly identify species. The application of sensitive mole cular approaches has obviated the necessity for laboratory amplification. S uch studies have found considerable evidence of genetic heterogeneity among isolates of Cryptosporidium from different species df: vertebrate, and the re is now mounting evidence suggesting that a series of host-adapted genoty pes/strains/species of the parasite exist. In this article, studies on the molecular characterisation of Cryptosporidium during the last 5 years are r eviewed and put into Perspective with the past and present taxonomy of the genus. The predictive value of achieving a sound taxonomy for the genus Cry ptosporidium with respect to understanding its epidemiology and transmissio n and controlling outbreaks of the disease is also discussed. (C) 1999 Aust ralian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.