Source and occurrence of Giardia and Cryptosporidium in Paris rivers

Abstract

This paper presents an investigation of the variability of concentrations of Giardia cyst and Cryptosporidium oocyst in two main rivers of Ile-de-France: the Seine (upstream from Paris) and its largest tributary: the Marne. The first goal of this study was to examine risk of presence of Cryptosporidium and Giardia at the drinking water treatment plants' intakes at high concentrations. A second goal was to study the relationship between parasite concentrations and a variety of more easily measured water quality parameters (microbial or physicochemical) which could be used as risk indicators. Two aspects were particularly addressed: the influence of upstream waste water discharges, and the influence of rain fall and river floods on parasite concentrations. Preliminary results of an ongoing study are also presented: they show possible influence of non-point sources on parasite concentrations. Overall results show that parasite sedimentation in rivers is high, urban run-off and resuspension of particles could be at certain times the main factors responsible for peak pathogen levels in raw water.

Genetic diversity of Cryptosporidium spp. in cattle in Michigan: implications for understanding the transmission dynamics

“…Recently, there has been increased interest in the assessment of the contribution of agricultural, environmental, ecologic, and climatologic factors to Cryptosporidium oocyst contamination in watershed and source water (Graczyk et al 2000;Rouquet et al 2000;Sischo et al 2000;Medema and Schijven 2001;Ono et al 2001;Jellison et al 2002). The use of high-resolution molecular tools and systematic sampling in combination with conventional methodologies could lead to a better understanding of the ecology of cryptosporidiosis in different environmental settings.…”

The Impact of Cattle Grazing in High Elevation Sierra Nevada Mountain Meadows over Widely Variable Annual Climatic Conditions

“…The oocysts can settle into river sediments where they can survive for prolonged periods of time. Heavy precipitation can resuspend oocysts at a later point [40][41][42].…”

Effects of weather and river flow on cryptosporidiosis

“…Sewage effluent has also been recognised as a source of Cryptosporidium in rivers by a variety of authors (Graczyk et al 2000;Roquet et al 2000) and in the UK 40% of all Cryptosporidium cases may be sewage-related (McLaughlin et al 2000). Once the Cryptosporidium has been washed into rivers the cool and moist conditions are ideal for its survival.…”

“…Once the Cryptosporidium has been washed into rivers the cool and moist conditions are ideal for its survival. However, the oocysts may not simply remain suspended in the water column but can pass into river sediments (Roquet et al 2000) where they can survive for extended periods (Robertson et al 1992) and be resuspended at a later stage.…”