Abstract
A survey was conducted on the prevalence of internal parasites in 450 racehorses necropsied in Tokyo, Japan, during the period 1980 to 1989. Large strongyles were found in 31.8% and verminous aneurysms in 36.4% o f the horses. Parascaris equorum was found in 14.4% o f all the horses, but in 19.4% of those less than three years old. Setaria equina was found in the peritoneal cavity of 16.2% of the horses. Oxyuris equi, Anoplocephala perfoliata and larvae of Gasterophilus intestinalis were found in 0.4%, 33.1 % and 9.3% o f the horses, respectively. The rate o f in fection with each parasite was less than that in the previous surveys and this might result from the proper application o f highly effective anthelmintic drugs to racehorses in recent years.
