Searching for ivermectin resistance in a Strongylidae population of horses stabled in Poland

BACKGROUND There are no available studies describing the possible resistance of strongyles to ivermectin in horses in Poland. One hundred seventy three horses from nine stud farms from South-Western Poland were studied. The effectiveness of ivermectin was studied on the 14th day after ivermectin administration using the fecal egg count reduction test, and a long-term observation of the egg reappearance period was carried out. The fecal study was carried out using a modified McMaster method, which typically detects 20 eggs per gram of stool. The results were subjected to statistical analysis that enabled quantification of the eggs in the stool samples. RESULTS The study revealed high efficacy of ivermectin on the 14th day after administration without a shortening of the egg reappearance period. CONCLUSION The results indicate that strongyles resistance to ivermectin in Poland is not a serious problem.