Abstract
Observations were made on the intestinal threadworm (Strongyloides westeri) and ascarid (Parascaris equorum) in field studies in 373 Thoroughbred foals on nine farms in Central Kentucky (USA) in 2013. Qualitative examination was made of feces of the foals for presence of S. westeri and P. equorum eggs. The main purpose of the prevalence study was to obtain current data on S. westeri in Thoroughbred foals. This was done to compare these findings with earlier studies in this geographical area where the prevalence of this parasite has been very low the last several decades. All the foals except on one farm had been treated one or more times with a parasiticide before the study. Prevalence of S. westeri in foals was 0 to 3 % on two farms, 6 to 9 % on three farms, and 20 to 51 % on four farms. The prevalence of P. equorum in foals was 0 to 14 % on three farms, 27 to 38 % on three farms, and 46 to 51 % on three farms. Effect of drugs given before the current study, on the prevalence of the two parasitic nematode species, is discussed. Also, three field tests were done by the present authors to evaluate activity of three individual or combination of drugs against ascarids. Evaluation was somewhat limited because, on two of the farms, a relatively small number of foals was passing ascarid eggs before treatment. However, oxibendazole and oxibendazole/piperazine combination were much more efficacious than fenbendazole.
Molecular detection of
Strongyloides westeri
in Australian Thoroughbred foals
