The Fate and Transport of Cryptosporidium parvum Oocysts in the Soil

Abstract

Cryptosporidium parvum (C. parvum) is a protozoan pathogen that is commonly present in surface water used for recreation, treated and untreated sewage and even drinking water. The zoonotic protozoan parasite C. parvum poses a significant risk to public health and has become a global concern to the water resource management since the 1993 outbreak in Milwaukee, US (Fayer, 2008). Ingestion of a small number of Cryptosporidium oocysts of can lead to potentially fatal consequences for immuno-suppressed individuals and it is thought that infection can be caused by even a single oocyst (Rose, 1997). At present, no specific drug treatment exists for cryptosporidiosis. C. parvum oocysts are biologically dormant yet resistance to the levels of chlorine routinely used in potable water treatment thus making waterborne transmission of cryptosporidiosis one of the most prominent public health concerns worldwide (Fayer, 2008). The main source of C. parvum oocysts is from infected calves when agricultural water including runoff, infiltration and subsurface flow from dairies, calving house, silage and grazing lands may be loaded with high concentrations of oocysts. Thus, the fate and transport of Cryptosporidium oocysts in the soil is of critical importance to manage and assess risk (Pachepsky et al., 2006). Thus, three key processes are evaluated in this study, including i) oocyst survival in the soil, ii) the attachment of oocysts to soil particles and iii) the transport of oocyst with physical straining in porous soils. Our study may provide an insight into the oocyst life cycle in the soil and help us make a better risk assessment.