AbstractsMedical & Health Science

Parasitic infections can be a threat to the health and the wellbeing of dogs and humans. Dog feces can be screened for the patency of helminth eggs of protozoan cysts or oocysts for several purposes: determination of the need of deworming, diagnosing of infections and control of therapy efficacy. For this, different methods of parasitological fecal examination exist. The aim of the study was to compare the reliability of centrifugation-sedimentation-flotation, passive flotation and McMaster. Feces samples (n=24) were of unknown egg concentrations. The number of positive outcomes, egg counts, and repeatability of the egg counts were recorded for each method and compared. The egg concentration was calculated from the egg counts. The suitability of the methods for both qualitative and quantitative fecal examination was compared. The amounts of feces and fluids were standardized for each of the methods. To assess the repeatability, triple measurements were made. For passive flotation (PF) a bench top test kit was used with a flotation solution of sodium nitrate (specific gravity: 1.20-1.21 g/ml) and a flotation phase of 30 minutes. Centrifugation-sedimentation-flotation (CSF) included sedimentation in tap water and flotation in a sugar solution with a specific gravity of 1.28-1.32 g/ml. Both were 2 minutes and centrifuge-assisted with a maximum gravitational acceleration of 3454- 13324 m/s2. For the McMaster the same flotation solution was used as for passive flotation. At least 5 minutes was waited after filling the counting chambers. Six samples only had negative test results, 10 contained Toxocara spp. eggs. Trichuris spp., Capillaria spp. and Strongyle-type eggs, as well as protozoan cysts (Giardia spp.) and oocysts (Isospora spp. or Eimeria spp.), and the yeast Cyniclomyces guttulatus were also detected but fewer times. Data analysis focused on Toxocara spp. eggs. No significant difference was found in sensitivity, although the McMaster measurements lead to less positive outcomes (21) than the other methods (27 and 28 for CSF and PF respectively). Egg counts were significantly the highest for the centrifugation-sedimentation-flotation method. Repeatability of the egg counts was not significantly different. Egg concentration estimates were significantly higher after McMaster than after the other procedures, although at relatively low concentrations (<500-2000 eggs per gram feces) CSF resulted in similar results as McMaster. An advice is given on when to use CSF and when McMaster for quantitative fecal examinations. Passive flotation should not be used for this goal but like CSF is suitable for qualitative measurements if the right procedure is used.