Cat-rodent Toxoplasma gondii Type II-variant circulation and limited genetic diversity on the Island of Fernando de Noronha, Brazil

Authors: SILVA, JEAN - Centro Nacional De Pesquisa E Conservação De Primatas Brasileiros; FERREIRA, FERNANDO - Universidad De Sao Paulo; DIAS, RICARDO - Universidad De Sao Paulo; AJEZENBERG, D - Inserm University Of Limoges; MARVULO, MARIA - Instituto Chico Mendes De Conservacao Da Biodiversidade; MAGALHAES, FERNANDO - Administração Do Distrito Estadual De Fernando De Noronha; FILHO, CARLOS - Administração Do Distrito Estadual De Fernando De Noronha; OLIVEIRA, SOLANGE - Universidad De Sao Paulo; SOARES, HERBERT - Universidad De Sao Paulo; FEITOSA, THAIS - Universidad De Sao Paulo; AIZAWA, JULIANA - Universidad De Sao Paulo; ALVES, LEUCIO - Federal Rural University Of Pernambuco; MOTA, RINALDO - Federal Rural University Of Pernambuco; Dubey, Jitender; GENNARI, SOLANGE - Universidad De Sao Paulo; PENA, HILDA - Universidad De Sao Paulo

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2017
Publication Date: 5/3/2017
Citation: Silva, J., Ferreira, F., Dias, R., Ajezenberg, D., Marvulo, M., Magalhaes, F., Filho, C., Oliveira, S., Soares, H., Feitosa, T., Aizawa, J., Alves, L., Mota, R., Dubey, J.P., Gennari, S., Pena, H. 2017. Cat-rodent Toxoplasma gondii Type II-variant circulation and limited genetic diversity on the Island of Fernando de Noronha, Brazil. Parasites & Vectors. doi: 10.1186/s13071-017-2150-4.

Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating under cooked meat from infected animals and food and water contaminated with oocyst. Why some people become ill and even die from toxoplasmosis whereas others remain asymptomatic is largely unknown. The genetic characteristics of T. gondii strains are considered a factor in the pathogenesis on clinical disease. Both the prevalence of T. gondii infections and the severity of clinical toxoplasmosis are higher in children in mainland Brazil than in USA and Europe. The strains of Toxoplasma from mainland Brazil are highly diverse genetically. In the present study, the authors found that unlike the stains from mainland Brazil, the T. gondii strains isolated from a cat and 3 rats from the island Fernando de Noronha, off the coast of Brazil, are different and more like in Europe, and probably introduced from Europe and not the mainland Brazil. The results will be useful for parasitologists, biologists, and epidemiologists.

Technical Abstract: In Brazil, studies on animals and humans in mainland areas have shown that most strains of Toxoplasma gondii are pathogenic to mice and exhibit great genetic variability. In this study, using a set of 11 PCR-RFLP and 15 microsatellite markers, we isolated and genetically characterised T. gondii strains from one cat and three rats on Fernando de Noronha Island. The cat had antibodies to T. gondii, which were revealed using a modified agglutination test (MAT, cut-off 1:25) and the seroprevalence among the 46 rodents was 15.2%. Viable T. gondii was isolated from one cat (TgCatBrFN1), two brown rats (TgRatnoBrFN1 and TgRatnoBrFN2) and one black rat (TgRatraBrFN1). Unlike the strains from mainland Brazil, these isolates were not pathogenic to outbred mice. The genotypes of these strains were compared with strains previously isolated on the island and in mainland Brazil. The analysis based on microsatellite data showed a limited genetic diversity of T. gondii on Fernando de Noronha Island with the majority of strains clustered into the following three groups: type II, III, and Caribbean 1.Conclusions: There was little variation among strains within the same group, suggesting that the majority of strains circulating on Fernando de Noronha are derived from only a few strains that were recently introduced to the island, likely from imported cats. Except for the strain belonging to the Caribbean 1 group that originates from northeast Brazil, there was little evidence that strains from the other groups were introduced to Fernando de Noronha via mainland Brazil.