title: The Indian soft-furred rat, Millardia meltada, a new host for Nippostrongylus brasiliensis, showing androgen-dependent sex difference in intestinal mucosal defence.
abstract: Susceptibility of the Indian soft-furred rat, Millardia meltada, to infection with the intestinal helminth, Nippostrongylus brasiliensis, was examined. After subcutaneous infection with 1500 infective larvae (L3), daily faecal egg output (EPG) of both male and female animals reached a peak at 1 week post-infection (p.i.) with the same magnitude (about 20,000 epg faeces) and then rapidly decreased below detection level at around 2 weeks p.i. In male animals, however, after a transient cessation at 2 weeks p.i., parasite eggs reappeared in faeces 3 weeks afterwards, though the counts were far lower than the first peak. This phenomenon was rarely seen in female animals. High susceptibility of M. meltada to N. brasiliensis was confirmed by worm burdens. About 70% of the initial dose of larvae became adult worms in the intestine of male and female hosts. As suggested by the decline in egg counts, the majority of adult worms were expelled by 2 weeks p.i. The residual worm burden at 2 and 4 weeks p.i. was significantly higher in male than female animals. When orchidectomized males were infected with N. brasiliensis, the magnitude of residual worm burden was significantly reduced. On the other hand, ovariectomy did not affect the number of residual worms in females.
authors.affiliation: Department of Veterinary Pathology, Faculty of Agriculture, Miyazaki University, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Tiuria
authors.forename: Y
authors.initials: Y
authors.lastname: Horii
authors.forename: S
authors.initials: S
authors.lastname: Tateyama
authors.forename: K
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Y
authors.initials: Y
authors.lastname: Nawa
mesh_terms: D000728:Androgens / Q000502:physiology*; D000818:Animals; D002369:Castration; D005243:Feces / Q000469:parasitology; D005260:Female; D007413:Intestinal Mucosa / Q000276:immunology / Q000469:parasitology; D007421:Intestine, Small / Q000276:immunology* / Q000469:parasitology; D008297:Male; D009115:Muridae / Q000276:immunology* / Q000469:parasitology; D009559:Nippostrongylus / Q000276:immunology*; D010270:Parasite Egg Count; D012727:Sex Characteristics; D017206:Strongylida Infections / Q000276:immunology*
chemical_list: D000728:Androgens