Effect of Storage and Preservation of Horse Faecal Samples on the Detectability and Viability of Strongylid Nematode Eggs and Larvae

The aim of the study was to assess selected methods of storage and preservation of horse faecal samples on the detectability of eggs and survival rate of larvae of strongylid nematodes. Physical and chemical factors were found to have a significant effect on the egg detectability and survival of the larvae. The comparison of control and variously preserved samples revealed that each storage method affected the reliability of the results to some extent. Short-lasting, three-day freezing resulted in a decrease of detectability from 100% to 94.1%, with an equally significant decrease in the mean number of eggs per one gram of faeces, from 1,238.97 to 983.82. Extending the freezing period from 3 to 14 d had a highly significant effect on the prevalence, which was then 85.3%, while the EPG (eggs per gram) value decreased more than twice, compared to control samples, and was 503.68. Thirty-day freezing had no further effect on the parasitological indices, which did not differ significantly from those obtained after a fortnight of freezing. Storing samples in 4% formalin and 40% ethanol had a significantly more negative effect on the detectability of strongylid eggs. The prevalence in alcohol-preserved samples was 91.2% and the EPG was 247.79; the values for formalin-preserved samples were 88.2% and 153.68. The way of preserving faecal samples was also found to affect the viability of strongylid larvae.