FINDING INFECTIOUS PROTOZOAN PARASITES IN RECLAIMED WATER

The goal of this study was to evaluate the presence of infectious cysts and oocysts in primary effluent and reclaimed. The numbers of cysts collected from the reclaimed water during this study were considerably lower than those obtained in a similar study by Garcia et al. (2002), which limited the concentration of cysts available for a doseresponse study. Even with this limitation, the findings were somewhat similar. Only one gerbil (out of 3) fed a dose of 250 cysts (obtained from reclaimed water concentrates) was found to be excreting Giardia cysts 14 days post inoculation. Studies to identify the genotype of the cysts entering this water reclamation facility should be performed. Most importantly, the infectivity of these genotypes to gerbils should be quantified using the same dose-response experiment performed as part of this study. Finding a higher gerbil infectious dose for cysts originating from reclaimed water than observed with the H3 strain used here would be relevant to assessing the risk associated with reclaimed water.