title: Infection of mice with oocysts of Toxoplasma gondii by oral route showed differences of virulence from Brazilian RFLP genotypes BrI and BrIII.
abstract: South American strains of Toxoplasma gondii present higher genetic diversity than classical European strains. We compared the virulence of two non-archetypal Brazilian genotypes of T. gondii to mice. Oocysts of four isolates, two genotype BrI (TgCatBr71 and TgShBr11) and two BrIII (TgCatBr74 and TgCatBr60) were obtained from cats fed experimentally infected mice. After sporulation, 5.0×10(1) and 1.0×10(2) oocysts were orally administrated to Swiss albine mice in Experiments #1 and #2, respectively (4-10 mice/group). Humoral response from dead and surviving mice was analyzed on days 9 to 35 post-infection. Microscopic observations of lungs and brains were performed for tachyzoites and cysts visualization in fresh preparations. Negative results were tested by PCR. Virulence after infection with oocysts is dose dependent for genotype BrIII isolates, but not for BrI. Differences in mortality were observed among isolates from genotype BrIII on Experiment #1. Intra-genotype phenotypic variation related to the parasite stage of infection was demonstrated and this characteristic should be further studied and may influence future work regarding the role of virulence amid hosts.
authors.affiliation: Agência Paulista de Tecnologia dos Agronegócios, São Paulo State Agricultural and Supply Department, Rua Antônio Gomes Morgado, 340, CEP 18013-440 Sorocaba, São Paulo, Brazil. Electronic address: danichiebao@apta.sp.gov.br.
authors.forename: Daniela Pontes
authors.initials: DP
authors.lastname: Chiebao
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, CEP 05508-270 São Paulo, São Paulo, Brazil.
authors.forename: Hilda Fátima de Jesus
authors.initials: HFJ
authors.lastname: Pena
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, CEP 05508-270 São Paulo, São Paulo, Brazil.
authors.forename: Aline Diniz
authors.initials: AD
authors.lastname: Cabral
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, CEP 05508-270 São Paulo, São Paulo, Brazil.
authors.forename: Mayra Pereira
authors.initials: MP
authors.lastname: Rocca
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, CEP 05508-270 São Paulo, São Paulo, Brazil.
authors.forename: Estela Gallucci
authors.initials: EG
authors.lastname: Lopes
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, CEP 05508-270 São Paulo, São Paulo, Brazil.
authors.forename: Samantha Yuri Oshiro Branco
authors.initials: SYOB
authors.lastname: Valadas
authors.affiliation: Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Av. Duque de Caxias Norte, 225, CEP 13635-900 Pirassununga, São Paulo, Brazil.
authors.forename: Lara Borges
authors.initials: LB
authors.lastname: Keid
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, CEP 05508-270 São Paulo, São Paulo, Brazil.
authors.forename: José Henrique Hildebrand
authors.initials: JHH
authors.lastname: Grisi Filho
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, CEP 05508-270 São Paulo, São Paulo, Brazil.
authors.forename: Rodrigo Martins
authors.initials: RM
authors.lastname: Soares
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan; D001938:Brazil; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D051379:Mice; D033661:Oocysts / Q000502:physiology; D016133:Polymerase Chain Reaction / Q000662:veterinary*; D012150:Polymorphism, Restriction Fragment Length; D011247:Pregnancy; D014122:Toxoplasma / Q000235:genetics* / Q000472:pathogenicity; D014124:Toxoplasmosis, Animal / Q000469:parasitology*; D014774:Virulence / Q000235:genetics
chemical_list: D000913:Antibodies, Protozoan
keywords: Brazilian genotypes; Lethality; Oral infection; Serology; Toxoplasmosis