A novel method for the isolation of gastro-intestinal nematode eggs that allows automated analysis of digital images of egg preparations and high throughput screening

A simple and robust method for the isolation of gastro-intestinal nematode eggs from faeces is described that uses both salt- and sugar solutions for flotation. Application of this 'salt-sugar' isolation method to large numbe rs of faecal samples of adult dairy cows indicates a 3- or 4-fold reduction in the proportion of e.p.g.-negative cows relative to studies that used ot her techniques for egg isolation. The procedure detects more eggs than the Wisconsin flotation method in replicate samples and in spiked egg-free faec es. The number of recovered eggs in spiked faecal samples is linear over a range of egg concentrations, and the transparent faecal preparations that r esult from the protocol can be stored as digital images which can be used a s input for an efficient automated egg-counting procedure. The increased ra te of processing of faeces combined with the large reduction of the percent age of e.p.g.-negative cows allows more accurate analysis of large numbers of adult or resistant animals for studies of nematode parasitism.