[Effect of distribution of eggs of strongyles and Parascaris equorum in faecal samples of horses on detection with a combined sedimentation-flotation method].

OBJECTIVE

Results of parasitological examination of faecal aliquots may vary between diagnostic laboratories. To examine whether inhomogeneous distribution of worm eggs in faecal samples is responsible for this observation, horse faeces provided for routine diagnosis of helminth infection were examined. Distribution of worm eggs was assessed by examining aliquots taken from different locations of the faecal sample by a combined sedimentation-flotation method (KSFV). In addition, it was tested, whether the homogenization of a larger amount (minimum of 40 g) of faeces before performing KSFV improved reproducibility of the method.

MATERIAL AND METHODS

51 faecal samples of horses were examined three times in parallel by KSFV with ZnSO4 solution. 10 g aliquots were taken from the margin (R), from inside (I) and from both locations (G). The remaining amount of faeces was weighed, suspended with water 1:1 and homogenized. Subsequently, three subsamples, each consisting of 20 g of this suspension, were taken and examined by KSFV.

RESULTS

The egg numbers of the nematodes (strongyles and Parascaris equorum ) found in samples that originated from different locations were similar and variation was low. The homogenization of a larger amount of faeces had no relevant impact on egg counts of these nematodes.

CONCLUSION AND CLINICAL RELEVANCE

Nematode infections are relevant and frequently occurring in the horse, and reliable assessment of worm egg excretion is a critical aspect for rational planning of control measures. It could be shown that the distribution of nematode eggs (strongyles and Parascaris equorum ) in horse faeces is quite even and results are in principle reproducible if 10 g faeces are examined by KSFV. The homogenization of a larger amount of faeces does not improve the sensitivity or reproducibility of KSFV, and is thus dispensable. For diagnostic purposes, it is advisable to ship approximately 50g of horse faeces to the laboratory.