use of a sentinel system for field measurements of cryptosporidium parvum oocyst inactivation in soil and animal waste.a small-volume sentinel chamber was developed to assess the effects of environmental stresses on survival of sucrose-percoll-purified cryptosporidium parvum oocysts in soil and animal wastes. chambers were tested for their ability to equilibrate with external chemical and moisture conditions. sentinel oocysts were then exposed to stresses of the external environment that affected their viability (potential infectivity), as indicated by results of a dye permeability assay. preliminary laboratory ...199910223991
cryptosporidium and dairy cattle in the catskill/delaware watershed: a quantitative risk assessment.we carried out a study to estimate the public health risk posed by dairy cattle located in new york city's catskill/delaware watershed, as measured by daily c. parvum-like oocyst loading. a monte carlo simulation model that takes into account the nature of the dairy cattle population within the target area, age-specific incidence/prevalence rates, as well as differential fecal production and oocyst-shedding intensity rates was used to address the objectives. additionally, the model was designed ...200718093047
incidence of cryptosporidium parvum in the dairy cattle population in a new york city watershed.a longitudinal study of 2-year duration was conducted to determine the risk, as measured by incidence rate, of cryptosporidium parvum infection among dairy cattle in the catskill/delaware watershed of new york city (nyc), and the factors that predispose animals to the likelihood of infection. a proportional sampling scheme with follow up at quarterly farm visits was employed for heifers and cows. additionally, all calves born on the 39 study farms were sampled once during the first four weeks of ...200515955631
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