cross-sectional study of faecal shedding of giardia duodenalis and cryptosporidium parvum among packstock in the sierra nevada range. | faecal specimens from 305 horses and mules used as packstock at one of 17 commercial or governmental (national park service, us forest service) operations were examined for giardia duodenalis and cryptosporidium parvum using immunofluorescent microscopy. fourteen packstock (4.6%) were shedding g. duodenalis cysts, with herd-level prevalences ranging 0-22%. number of packstock in the corral, size of corral and density of packstock in the corral were associated with the odds of shedding g. duodena ... | 2000 | 10836481 |