title: Cavia porcellus as a model for experimental infection by Trypanosoma cruzi.
abstract: The guinea pig (Cavia porcellus) is a natural reservoir for Trypanosoma cruzi but has seldom been used as an experimental infection model. We developed a guinea pig infection model for acute and chronic Chagas disease. Seventy-two guinea pigs were inoculated intradermally with 10(4) trypomastigotes of T. cruzi strain Y (experimental group); 18 guinea pigs were used as control group. Eight animals from the experimental group and two from the control group were sacrificed 5, 15, 20, 25, 40, 55, 115, 165, and 365 days after inoculation. During the acute phase (15 to 55 days), we observed parasitemia (with a peak on day 20) and positive IgM and IgG Western blots with anti-shed acute-phase antigen bands. The cardiac tissue showed vasculitis, necrosis (on days 40 to 55), moderate to severe inflammation, and abundant amastigote nests. Smaller numbers of amastigote nests were also present in kidney, brain, and other organs. In the early chronic phase (115 to 165 days), parasitemia disappeared and anti-T. cruzi IgG antibodies were still detectable. In cardiac tissue, the number of amastigote nests and the grade of inflammation decreased. In the chronic phase (365 days), the cardiac tissue showed vasculitis and fibrosis; detectable parasite DNA was associated with higher grades of inflammation. The experimental T. cruzi infection model in guinea pigs shows kinetics and pathologic changes similar to those of the human disease.
authors.affiliation: Asociación Benéfica PRISMA, San Miguel, Lima, Peru.
authors.forename: Yagahira E
authors.initials: YE
authors.lastname: Castro-Sesquen
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.forename: Verónica
authors.initials: V
authors.lastname: Yauri
authors.forename: Noelia
authors.initials: N
authors.lastname: Angulo
authors.forename: Manuela
authors.initials: M
authors.lastname: Verastegui
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Velásquez
authors.forename: Charles R
authors.initials: CR
authors.lastname: Sterling
authors.forename: Diana
authors.initials: D
authors.lastname: Martin
authors.forename: Caryn
authors.initials: C
authors.lastname: Bern
mesh_terms: D000210:Acute-Phase Reaction; D000818:Animals; D015153:Blotting, Western; D014355:Chagas Disease / Q000276:immunology / Q000469:parasitology* / Q000473:pathology; D002908:Chronic Disease; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005355:Fibrosis / Q000209:etiology* / Q000473:pathology; D006168:Guinea Pigs; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007249:Inflammation / Q000209:etiology* / Q000473:pathology; D018512:Parasitemia / Q000209:etiology* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014349:Trypanosoma cruzi / Q000276:immunology / Q000472:pathogenicity*; D014657:Vasculitis / Q000209:etiology* / Q000473:pathology
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012333:RNA, Messenger