title: Acquired resistance against Schistosoma bovis after single or repeated low-level primary infections in goats.
abstract: Experimental Schistosoma bovis infections were studied in groups of six goats for 32 weeks. Two types of primary infections, a single exposure to 400 cercariae per goat or repeated (trickle) exposure to 200 cercariae per goat weekly for 10 weeks, were followed by a challenge infection with 2000 cercariae per goat in week 16 of the experiment. Periods of high faecal egg excretion were associated with reduced weight gain, anaemia, hypoalbuminaemia and blood eosinophilia; these changes gradually diminished with decreasing faecal egg excretion but never disappeared completely. The pathogenic effects of the trickle exposure exceeded those of the single primary exposure. After the challenge, the goats excreted few or no additional eggs and no additional clinicopathological changes were observed in the group previously exposed to a trickle infection. However, the primary single infection did not provide full protection against the effects of the challenge infection.
authors.affiliation: Royal Veterinary and Agricultural University, Department of Veterinary Microbiology, Frederiksberg, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Monrad
authors.forename: N O
authors.initials: NO
authors.lastname: Christensen
authors.forename: P
authors.initials: P
authors.lastname: Nansen
authors.forename: M V
authors.initials: MV
authors.lastname: Johansen
authors.forename: R
authors.initials: R
authors.lastname: Lindberg
mesh_terms: D000818:Animals; D001835:Body Weight; D004804:Eosinophils; D005243:Feces / Q000469:parasitology; D015511:Goat Diseases / Q000276:immunology* / Q000469:parasitology*; D006041:Goats; D006454:Hemoglobins / Q000378:metabolism; D007113:Immunity, Innate; D012552:Schistosomiasis / Q000097:blood / Q000276:immunology / Q000662:veterinary*; D012709:Serum Albumin / Q000378:metabolism; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D012709:Serum Albumin