Primary Investigators: Spencer Greenwood, Juan Aguirre Co-Primary Investigators: Javier Sanchez, Henrik Stryhn, J McClure, Jeffrey Davidson, Jessica Willis

Contamination of oysters occurs predominantly in coastal or estuarine environments with wastewater sewage discharge and agricultural run-off from farms. Cryptosporidium spp. is a zoonotic protozoan parasite that has been detected in many shellfish species in both fecal- contaminated and clean oyster growing areas across the globe. Despite this fact, no data are available on oocyst concentrations in harvest-zone waters or in oysters harvested in PEI. An assessment of the levels of this parasite in areas where the health authorities permit oyster harvesting is an important public health concern.

The primary objective of this project is to determine the concentrations of Cryptosporidium oocysts in water from three different shellfish harvest zones (prohibited, restricted and approved) during the spring season after a rainfall event (which would indicate a higher risk of contamination). Some oyster sampling will be done concurrently in order to compare the concentrations of the parasite with findings from unpublished data by Willis et al (2012) and to provide information about the accumulation of oocysts in oysters in the field. Our results will be linked to a risk assessment model for the probability of human illness due to consumption of contaminated oysters with Cryptosporidium spp in PEI.

We hypothesize that: 1) The number of oocysts will be greatest in the prohibited zones, followed by restricted zones, with zero prevalence in approved zones, and; 2) The level of oocysts in the water will be increased by rainfall events.