Sensitivity and efficiency of selected coproscopical methods-sedimentation, combined zinc sulfate sedimentation-flotation, and McMaster method.

Abstract

Coproscopical methods used in veterinary-parasitological diagnostics were validated according to their sensitivity (Se) and egg recovery rate [efficiency (Ef)]. Validation of the combined sedimentation-flotation method and the modified McMaster method was performed by using feces spiked with eggs of Ancylostoma caninum, Uncinaria stenocephala, Cooperia oncophora, cyathostomins, Ascaris suum, Toxascaris leonina, Toxocara canis, Trichuris vulpis, Moniezia expansa, and Anoplocephala perfoliata. For validation of the sedimentation method, Fasciola hepatica eggs were used. With the combined sedimentation-flotation method using ZnSO4 as flotation medium [specific gravity (SG) 1.30], 5g fecal samples of all tested parasite species (concentration levels 1, 5, 10, 20, 40, 60, and 80epg) were reproducibly detected "positive" (100% Se) as of 80epg. The Ef of the combined sedimentation-flotation method, defined as percentage of rediscovered eggs, revealed clear differences between parasites and showed the highest value for cyathostomins and the lowest for U. stenocephala and T. leonina eggs. The average Ef for all parasite species at 80epg was 1.50%. With the McMaster method (concentration levels 1, 30, 50, 80, 100, 500, and 1000epg), all tested parasite species were detected reliably positive as of 500epg with a mean Ef of 46.4%. When evaluating the sedimentation method (concentration levels 1, 5, 10, 15, 20, 25, and 30epg), F. hepatica eggs were reproducibly found in 5g fecal samples as of 20epg with 20.0% Ef. The result that the combined zinc sulfate sedimentation-flotation method (SG 1.30) as flotation medium provides diagnostic certainty only as of 80epg has to be considered at preventing zoonoses. If pet owners wish to prevent any zoonotic infection ("zero tolerance"), a monthly anthelminthic treatment should be advised instead of monthly fecal examinations.