Submitted to: Journal of Water and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 4, 2004
Publication Date: September 1, 2009
Citation: Fayer, R., Orlandi, P., Perdue, M.L. 2009. Virulence factor activity relationships for Hepatitis E and Cryptosporidium. Journal of Water and Health. 7(1):55-63.
Interpretive Summary: The central premise of Virulence Factor Activity Relationships (VFARS) is to relate structural and biochemical components of microorganisms to predicting the ability of an organism to cause disease. Two pathogens of concern to animal and human welfare are Hepatitis E Virus and the protozoan parasites in the genus Cryptosporidium. The present manuscript describes factors of each that relate to the VFARS approach to waterborne pathogens being considered by the US Environmental Protection Agency.
Hepatitis E Virus and Cryptosporidium are waterborne pathogens, each consisting of distinct taxa, genotypes, and isolates that infect humans, nonhuman animal species, or both. Some are associated with disease, others are not. Factors contributing to disease are extremely complicated, possibly involving differences in one or more traits associated with an organism's taxon, genotype, or isolate and its infectious dose, and age or condition, as well as the host's physiology and immune status. Potential virulence factors have not yet been identified for HEV. Putative virulence factors for Cryptosporidium might be found in recently recognized genes involved in processes such as excystation, adherence to host cells, invasion, intracellular maintenance, and host cell destruction.