Aims:  To determine the counts and/or prevalence in fresh bovine faeces of Escherichia coli, enterococci, Campylobacter, Salmonella, shiga toxin‐producing E. coli (STEC), Giardia and Cryptosporidium, as inputs to numerical models designed to estimate microbial loadings on pasture grazed by cattle in New Zealand. Methods and Results:  In each season over one year, samples of freshly deposited bovine faeces were collected from four New Zealand dairy farms (n = 155), and enumerated for E. coli, enterococci, Campylobacter, Giardia and Cryptosporidium. They were also tested for the presence of Salmonella and STEC. The overall median bacterial counts (g−1 wet weight) were E. coli– 5·9 × 106; enterococci – 1·3 × 104; Campylobacter– 3·9 × 105. All counts were highly variable within and between samplings, and few seasonal or regional patterns emerged. However, mean Campylobacter counts were consistently higher in spring. No Salmonella spp. was detected, and only two samples were positive for STEC. Cryptosporidium and Giardia were isolated from 5·2% and 4·5% of the samples, respectively, yielding low numbers of (oo)cysts (1–25 g−1 and 1–17 g−1, respectively). Conclusions:  Fresh bovine faeces are a significant source of E. coli, enterococci and Campylobacter on New Zealand pastures, although numbers are likely to vary markedly between faecal samples. Significance and Impact of the Study:  The study provides the first significant set of indicator and pathogen counts for one of the largest sources of faecal contamination of natural waters in New Zealand, and will be used to model these inputs.

The survival of enteric bacteria in 10 freshly collected sheep fecal samples on pastures was measured in each of four seasons. Ten freshly collected feces were placed on pasture, and concentrations of Escherichia coli, enterococci, and Campylobacter spp. were monitored until exhaustion of the fecal samples. In all four seasons, there was an increase in enterococcal concentrations by up to 3 orders of magnitude, with peak concentrations recorded between 11 and 28 days after deposition. E. coli concentrations increased in three out of four seasons by up to 1.5 orders of magnitude, with peak concentrations recorded between 8 and 14 days after deposition. The apparent growth of E. coli and enterococci was strongly influenced by the initial water content of the feces and the moisture gained during periods of rehydration following rainfalls. Conversely, the results suggested that dehydration promoted inactivation. Campylobacter spp. did not grow and were rapidly inactivated at a rate that tended to be faster at higher temperatures. Pulsed-field gel electrophoresis (PFGE) of a selection of Campylobacter spp. suggested that these survival data are applicable to a range of Campylobacter spp., including the most frequently isolated PFGE genotype from sheep in New Zealand, and to genotypes previously observed to cause disease in humans. The results of this study are currently being incorporated into a fecal microbe reservoir model that is designed to assist water managers' abilities to estimate microbial loads on pastures grazed by sheep, including the influence of factors such as rainfall and temperature.

Freshly excreted droppings from Canada geese (n 080), black swans (n 080), ducks (n 080) and gulls (n080) were collected from sites around New Zealand. The droppings were enumerated for Escherichia coli, enterococci and Salmonella spp., and for the presence/absence of Cryptosporidium spp. Overall prevalence of E. coli and enterococci in samples was 95% and 94%, respectively. Cryptosporidium spp. was detected in 2% of the samples, whereas no Salmonella spp. were detected in the survey. Preliminary estimates of daily microbial outputs suggest that ducks will produce the highest loadings of E. coli and enterococci per bird, whereas Canada geese will produce the highest loadings of Campylobacter spp. per bird. This study provides the first set of indicator and pathogen counts for one of the largest sources of diffuse faecal contamination of natural waters in New Zealand.

Cryptosporidium parvum is a waterborne pathogen, yet no suitable surrogate has been established for quantifying its filtration removal in porous media. Carboxyl polystyrene microspheres with size, density, and shape similar to C. parvum were coated with biotin (free and containing amine, NH(2)) and glycoprotein. These biomolecules have isoelectric points similar to C. parvum (pH ≈ 2), and glycoprotein is a major type of surface protein that oocysts possess. Zeta potential (ζ) and filtration removal of particles in sand of two different grain sizes were examined. Compared to unmodified microspheres, modified microspheres achieved a superior match to the oocysts in ζ, concentration, mass recovery, and collision coefficient. They showed the same log reduction in concentration as oocysts, whereas results from unmodified microspheres deviated by 1 order of magnitude. Of the three types of modified microspheres, glycoprotein-coated microspheres best resembled oocyst concentration, despite having ζ similar to NH(2)-biotin-coated microspheres, suggesting that surface protein also played an important role in particle attachment on solid surfaces. With further validation in environmental conditions, the surrogates developed here could be a cost-effective new tool for assessing oocyst filtration in porous media, for example, to evaluate the performance of sand filters in water and wastewater treatment, water recycling through riverbank filtration, and aquifer recharge.

The incidence and prevalence of micro-organisms in ovine faeces as potential sources of diffuse pollution to natural waters were determined. Faecal samples from lambs at slaughter (N 0105) and sheep at pasture (N 0220) were collected. E. coli, enterococci and Campylobacter spp. were enumerated in lambs (6.04 )10 8 , 1.44 )10 7 and 3.3 )10 5 g (1 respectively) and sheep (1.62 )10 7 , 6.8 )105 and 2.08 )10 3 g (1 respectively). Campylobacter spp., Salmonella spp. and Shiga toxin producing E. coli (STEC) were present in 80.9%, 1.9% and 3.8% of lamb samples, and 30.4%, 0% and 0.9% of sheep samples respectively. Cryptosporidium spp. and Giardia spp. were present in 28.6% and 37.1% of the lamb faecal samples, and 3.6% of sheep samples were positive for Cryptosporidium spp. The results of this study will be incorporated into models for estimating the potential impact of ovine faeces on natural waters.