Comparative Parasitology 68(2) 2001 - Peru State College
Comparative Parasitology 68(2) 2001 - Peru State College
Comparative Parasitology 68(2) 2001 - Peru State College
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264 COMPARATIVE PARASITOLOGY, <strong>68</strong>(2), JULY <strong>2001</strong><br />
was recovered from the rats collected in the<br />
paddy and hilly areas but not from those in the<br />
residential area.<br />
The differences in species composition and<br />
prevalence among the habitats could be explained<br />
by the biological characters of each<br />
helminth and by the environmental conditions.<br />
Because members of Notocotylus require a<br />
freshwater snail as the intermediate host (cf.<br />
Yamaguti, 1975), their presence in the paddy<br />
fields is reasonable. The hilly area surveyed in<br />
the present study contained many small ponds<br />
that might provide habitats for the snails. Also<br />
not unexpected is that G. neoplasticum and M.<br />
moniliformis were found only in the rats captured<br />
around the houses, because their intermediate<br />
hosts, usually cockroaches, are abundant<br />
in the residential areas. Nippostrongylus<br />
brasiliensis and Strongyloides spp. require<br />
moist soil for their embryonic and larval development<br />
and transmission. Their low prevalence<br />
or absence in the residential areas<br />
seems to be due to the dried soil around the<br />
houses in that season. Syphacia muris, the<br />
only helminth with relatively stable prevalence<br />
among the habitats, has a quite simple<br />
life cycle passed nearly entirely within the<br />
body of the host, and hence, its prevalence is<br />
less affected by the external environment.<br />
We are deeply indebted to Dr. G. G. Musser,<br />
American Museum of Natural History, for his<br />
kindness in identifying the rat species and to<br />
Dr. S. Kamegai, Meguro Parasitological Museum,<br />
for his kind consultation on Notocotylus<br />
sp.<br />
Literature Cited<br />
Durette-Desset, M. C. 1970. Caracteres primitifs de<br />
certains Nematodes Heligmosomes parasites de<br />
Murides et de Cricetides orientaux. Definition<br />