Abstract
Parasitological examination of the esophagus of 5, 204 cattle during the period from July, 1989 to July, 1990 revealed that 433 cattle from the 11 districts of Hokkaido harbored Gongylonema nematodes in their esophagus.
The nematode was identified as Gongylonema pulchrum by the following morphological characteristicsand measurements:(1) several longitudinal rows of plaques are present on the surface of the anterior part of the body, (2) both caudal alae are asymmetrical in shape and ornamented with numerous pedunculate papillae, (3) the spicules are unequal in length, (4) eggs have a thick shell and include an embryo when excreted in the feces.
Prevalence of Gongylonema pulchrum infections seems to be closely correlated with the incidence of coprophagus beetles, the intermediate host, in the pasture because bovine gongylonemiasis had two peaks in prevalence in Hokkaido in September and Feburary and the coprophagus beetles appeared in the pasture in spring and autumn.
Bovine gongylonemiasis appears to have become endemic in Hokkaido, because Gongylonema pulchrum infections have heen detected from almost all areas.
