title: Molecular and virulence characterization of Toxoplasma gondii strains isolated from humans in Portugal.
abstract: Toxoplasma gondii is an apicomplexan parasite responsible for toxoplasmosis which infects all warm-blooded vertebrates, including mammals and birds. The majority of studies conducted in Europe have revealed that more than 80 % of strains isolated from human infections belong to genotype II, whereas genotypes I and III are responsible for a small number of cases. Atypical and recombinant strains are generally associated with more severe infections. In Portugal, there is a lack of data concerning genetic diversity as the classical typing studies in humans have never been performed. We aimed to determine the Sag2 and microsatellite-based (TUB2, TgM-A, W35, B17, B18) genotypes of T. gondii isolated from humans in Portugal, as well as to study their virulence in mice. We analyzed 48 strains from congenital and acquired toxoplasmosis collected during the last two decades. Sag2-based genotyping of T. gondii was achieved in all 48 strains where 35 (73 %) were classified as type II and 13 (27 %) were type I. The multilocus PCR of five microsatellites allowed the classification of 10 strains (21 %) as recombinant strains that had been previously identified as type II or I by Sag2 typing. Seven out of the 48 strains, including three type I, three recombinant, and one type I, were virulent in mice. This study constitutes the first evidence of recombinant strains circulating in Portugal in humans from congenital infection, highlighting the need for a better evaluation of these strains as their phenotype is still barely understood.
authors.affiliation: National Reference Laboratory of Parasitic and Fungal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal. anabela.vilares@gmail.pt.
authors.forename: Anabela
authors.identifier: http://orcid.org/0000-0003-0844-4442
authors.initials: A
authors.lastname: Vilares
authors.affiliation: National Reference Laboratory of Parasitic and Fungal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Gargaté
authors.affiliation: National Reference Laboratory of Parasitic and Fungal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.
authors.forename: Idalina
authors.initials: I
authors.lastname: Ferreira
authors.affiliation: National Reference Laboratory of Parasitic and Fungal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Martins
authors.affiliation: Research and Development Unit, Infectious Diseases Department, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.|Bioinformatics Unit, Infectious Diseases Department, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Gomes
mesh_terms: D000818:Animals; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D051379:Mice; D008813:Mice, Inbred ICR; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction; D011174:Portugal; D014122:Toxoplasma / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity*; D014123:Toxoplasmosis / Q000469:parasitology*; D014774:Virulence
keywords: Congenital; Genotype; Recombinant; Strain; Toxoplasma gondii