| environmental and geographical factors contributing to watershed contamination with cryptosporidium parvum oocysts. | cryptosporidium parvum is a waterborne parasite which infects cattle and produces life-threatening zoonosis in people with impaired immune systems. digital maps of 100-year floodplain boundaries, land use/cover, and livestock operations were used to select and characterize cattle farms in the floodplain area in lancaster county, pennsylvania, u.s.a. over 21% of the cattle farms were located within 100-year floodplain boundaries. on average, a single farm comprised 12.8 ha of pasture (including b ... | 2000 | 10702335 |