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Toxoplasma gondii genetic diversity in the Southern Region of Brazil and study of its population structure in the country

Grant number: 18/26071-5
Support type:Regular Research Grants
Duration: June 01, 2019 - May 31, 2021
Field of knowledge:Agronomical Sciences - Veterinary Medicine
Principal Investigator:Hilda Fátima de Jesus Pena
Grantee:Hilda Fátima de Jesus Pena
Home Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Assoc. researchers:Arlei Marcili ; Daniel Ajzenberg ; Herbert Sousa Soares ; Ricardo Augusto Dias ; Solange de Oliveira ; Solange Maria Gennari


Toxoplasmosis is a zoonosis of worldwide distribution. Brazil has one of the highest seroprevalence rates of Toxoplasma gondii in the world. Free-living chickens have been used for seroprevalence studies of T. gondii and genotypic characterization of isolates in order to understand the parasite population structure and its biological characteristics in different regions of the world. The isolates of T. gondii from South America are highly diverse and this diversity may be related to the occurrence of severe ocular and congenital toxoplasmosis. In Brazil, some lineages are widely distributed and are considered clonal and are called BrI, BrII and BrIII types, with low occurrence of classical clones I, II and III and predominance of "atypical" strains, but there are no recent studies on the structure of the parasite in Brazil, considering a representative panel of samples from all Brazilian regions. Archetypes I, II and III have been described only in the Southern Region. The objectives of the project are to determine the frequency of anti-T. gondii antibodies from hens raised in the rural areas of the municipalities with the lowest human development index (HDI) of the South Region, isolating T. gondii in the region, genotyping the isolates obtained (using PCR-RFLP, microsatellite analysis (MS) and introns sequencing), and, finally, the review of the parasite population structure in the country using MS. It is expected to understand the population structure of T. gondii in the Southern Region of Brazil, particularly regarding the impact of the circulation of the three classic clonal types I, II and III. It is also expected to understand the current structure of the agent, considering the five regions of the national territory, comparing the results found in the South Region with available data of genotyping of samples from other regions of Brazil, by MS, regarding the diversity of isolates and groups, existence of geographic subpopulations and occurrence of gene flow between two populations. (AU)