Search

This paper describes the development and application of a systematic methodology to identify and quantify risks in drinking water and recreational catchments. The methodology assesses microbial and chemical contaminants from both diffuse and point sources within a catchment using Escherichia coli, protozoan pathogens and chemicals (including fuel and pesticides) as index contaminants. Hazard source information is gathered by a defined sanitary survey process involving use of a software tool which groups hazards into six types: sewage infrastructure, on-site sewage systems, industrial, stormwater, agriculture and recreational sites. The survey estimates the likelihood of the site affecting catchment water quality, and the potential consequences, enabling the calculation of risk for individual sites. These risks are integrated to calculate a cumulative risk for each sub-catchment and the whole catchment. The cumulative risks process accounts for the proportion of potential input sources surveyed and for transfer of contaminants from upstream to downstream sub-catchments. The output risk matrices show the relative risk sources for each of the index contaminants, highlighting those with the greatest impact on water quality at a sub-catchment and catchment level. Verification of the sanitary survey assessments and prioritisation is achieved by comparison with water quality data and microbial source tracking. [ABSTRACT FROM AUTHOR]

u. ryan, c. read, p. hawkins, m. warnecke, p. swanson, m. griffith, d. deere, m. cunningham and p. cox. 2005.Currently cryptosporidiosis represents the major public health concern of water utilities in developed nations and increasingly, new species and genotypes ofCryptosporidiumare being identified in which the infectivity for humans is not clear. The complicated epidemiology ofCryptosporidiumand the fact that the majority of species and genotypes ofCryptosporidiumcannot be distinguished morphologically makes the assessment of public health risk difficult if oocysts are detected in the raw water supplies. The aim of this study was to use molecular tools to identify sources ofCryptosporidiumfrom the Warragamba catchment area of Sydney, Australia.Both faecal and water samples from the catchment area were collected and screened using immunomagnetic separation (IMS) and immunofluorescence microscopy. Samples that containedCryptosporidiumoocysts were genotyped using sequence and phylogenetic analysis of the 18S rDNA, and the heat-shock (HSP-70) gene. Analysis identified fiveCryptosporidiumspecies/genotypes includingC. parvum(cattle genotype),C. suis, pig genotype II, the cervid genotype and a novel goat genotype.Monitoring and characterization of the sources of oocyst contamination in watersheds will aid in the development and implementation of the most appropriate watershed management policies to protect the public from the risks of waterborneCryptosporidium.This study has shown that quantification by IMS analysis can be combined with the specificity of genotyping to provide an extremely valuable tool for assessing the human health risks from land use activities in drinking water catchments. [ABSTRACT FROM AUTHOR]

The development of Theileria mutans in the gut and haemolymph of its tick vector, Amblyomma variegatum, was studied by Giemsa-stained smears after the nymphal tick had completed engorgement on parasitaemic calves. Sexual stages occurred in the gut between five and seven days after repletion. The zygotes were observed in the gut from day 29 and the kinetes from day 30, i.e. three and four days after the nymphs moulted to adults. From day 34 kinetes were observed in the haemolymph. The developmental stages of T. mutans in the tick were compared with those of other Theileria spp. of cattle. [ABSTRACT FROM AUTHOR]