Biology and transmission of the gullet worm (Gongylonema pulchrum Molin, 1857)
2009
Sato, H., Yamaguchi Univ. (Japan). Faculty of Agriculture
The gullet worm, Gongylonema pulchrum Molin, 1857, is distributed widely in the world. It takes a wide spectrum of mammals as a definitive host, such as cattle, zebus, buffaloes, sheep, goats, deer, camels, pigs, wild boars, horses, donkeys, bears, rodents, monkeys, and human beings. Since C. A. Rudolphi recorded the worm in the esophagus of a European bear as 'Spiroptera ursi' in 1819, many species, junior synonyms of 'G. pulchrum' at present, have been erected for the worms collected from different mammalian hosts in different localities. This is ascribed to wide variations in measurable morphological characters of the gullet worms grown in different hosts. In Japan, since the first notice of its distribution in 1987, the gullet worm has been reported in cattle, deer, Japanese macaques, squirrel monkeys in zoo facilities, and three human patients. Recent genetic analyses of the gullet worms, which were collected from cattle and deer in Japan, demonstrated that two distinct genotypes might be prevalent respectively in cattle and deer. The results suggested that domestic and wild ruminants, at least in Japan, might keep separate transmission cycles of each genotype. The present view of G. pulchrum, having a wide host range, could be challenged from the viewpoint of actual transmission, or phylogeography of the gullet worm in each host species.
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