Multi-locus DNA sequencing of Toxoplasma gondii isolated from Brazilian pigs identifies genetically divergent strains

Frazão-Teixeira, Edwards; Natarajan, Sundar; Dubey, J. P.; Grigg, Michael E.; Oliveira, Francisco Carlos Rodrigues de

doi:10.1016/j.vetpar.2010.09.030

Cited by 34 publications

(23 citation statements)

References 31 publications

(47 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These results are consistent with studies that defined the BrI genotype as virulent, BrIII as avirulent, and BrII as intermediate virulent [5], [22]. However, other studies did not find this association [7], [23]. Moreover, the high genetic diversity of T. gondii in Brazil [1] makes this association even more complex.…”

Section: Discussionsupporting

confidence: 89%

Overlapping Toxoplasma gondii Genotypes Circulating in Domestic Animals and Humans in Southeastern Brazil

et al. 2014

View full text Add to dashboard Cite

Although several Toxoplasma gondii genotyping studies have been performed in Brazil, studies of isolates from animals in the state of Minas Gerais are rare. The objective of this study was to conduct a genotypic characterization of T. gondii isolates obtained from dogs, free-range chickens, and humans in Minas Gerais and to verify whether the T. gondii genotypes circulating in domestic animals correspond to the genotypes detected in humans. Genetic variability was assessed by restricted fragment length polymorphism at 11 loci (SAG1, 5′+3′SAG2, SAG2 alt, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). Twelve different genotypes were identified among the 24 isolates studied, including 8 previously identified genotypes and 4 new genotypes. The genetic relationship of the 24 T. gondii isolates, together with the genotypes previously described from 24 human newborns with congenital toxoplasmosis, revealed a high degree of similarity among the genotypes circulating in humans and animals in Minas Gerais. The most common genotypes among these species were BrII, BrIII, ToxoDB #108, and ToxoDB #206. Restricted fragment length polymorphism at the CS3 locus of these 48 isolates showed that the majority of isolates presented alleles I (50%) or II (27%). Isolates harboring allele III at the CS3 locus presented low virulence for mice, whereas those harboring alleles I or II presented higher virulence. These results confirm the utility of marker CS3 for predicting the virulence of Brazilian isolates of T. gondii in mice. No association was found between the allele type and clinical manifestations of human congenital toxoplasmosis. This is the first report of T. gondii genotyping that verifies the overlapping genotypes of T. gondii from humans and animals in the same geographic region of Brazil. Our results suggest that there is a common source of infection to the species studied, most likely oocysts contaminating the environment.

show abstract

Section: Discussionsupporting

confidence: 89%

Overlapping Toxoplasma gondii Genotypes Circulating in Domestic Animals and Humans in Southeastern Brazil

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Thus, there is no clear correlation between the genotypes of the isolates of T. gondii obtained from newborns in the state of Minas Gerais in Brazil and virulence to mice. A recent study in Brazil has also not shown any concrete evidence of correlation between virulence of T. gondii in mice and different genotypes (38).…”

Section: Sag2 Sag3 Btub Gra6 C22-8 C29-2 L358 Pk1 Apicomentioning

confidence: 87%

Genetic Characterization of Toxoplasma gondii Revealed Highly Diverse Genotypes for Isolates from Newborns with Congenital Toxoplasmosis in Southeastern Brazil

et al. 2013

View full text Add to dashboard Cite

e Recent studies of Toxoplasma gondii isolates from animals in Brazil have revealed high genetic diversity. Many of these isolates are virulent to mice. It is speculated that these isolates may also be virulent to humans. However, there is very limited data regarding T. gondii strains from human infection. Therefore, it is not clear whether there is any association between parasite genotypes and disease phenotypes. In this study, a total of 27 T. gondii strains were isolated from humans with congenital toxoplasmosis in Minas Gerais state, Brazil. The genetic variability was assessed by restricted fragment length polymorphism in 11 loci (SAG1, 5= plus 3= SAG2, alternative [alt.] SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). Genetic analysis of 24 strains revealed 14 different genotypes, including 7 previously identified from animals and 7 new types. The widespread genotype BrII accounted for 29% (7/24) of the isolates and was the dominant genotype involved in this study. This is the first report of genotyping of T. gondii isolates obtained from blood samples from newborns with congenital toxoplasmosis. Genotypic characterization of these isolates suggests high genetic diversity of T. gondii in this human population in Brazil. Future studies are needed to determine the source of contamination of this human population.

show abstract

“…Some of these distinct strains likely represent recombinants of the three main clonal types based on their allelic combinations, but this cannot be confirmed without further sequencing analysis, since this typing scheme was specifically designed to detect polymorphisms inherent to the archetypal strains (Su et al, 2006). It is increasingly evident that apparent recombinants of the three archetypal lineages detected by RFLP analysis are often later re-classified by DNA sequencing as genetically distinct admixtures bearing many non-archetypal alleles (Boyle et al, 2006; Frazao-Teixeira et al, 2011; Grigg et al, 2001a; Khan et al, 2006; Su et al, 2010). …”

Section: Toxoplasma In Wildlifementioning

confidence: 99%

Population genetics of Toxoplasma gondii: New perspectives from parasite genotypes in wildlife

Wendte

Gibson

Grigg

2011

Veterinary Parasitology

View full text Add to dashboard Cite

Toxoplasma gondii, a zoonotic protozoal parasite, is well-known for its global distribution and its ability to infect virtually all warm-blooded vertebrates. Nonetheless, attempts to describe the population structure of T. gondii have been primarily limited to samples isolated from humans and domesticated animals. More recent studies, however, have made efforts to characterize T. gondii isolates from a wider range of host species and geographic locales. These findings have dramatically changed our perception of the extent of genetic diversity in T. gondii and the relative roles of sexual recombination and clonal propagation in the parasite’s lifecycle. In particular, identification of novel, disease-causing T. gondii strains in wildlife has raised concerns from both a conservation and public health perspective as to whether distinct domestic and sylvatic parasite gene pools exist. If so, overlap of these cycles may represent regions of high probability of disease emergence. Here, we attempt to answer these key questions by reviewing recent studies of T. gondii infections in wildlife, highlighting those which have advanced our understanding of the genetic diversity and population biology of this important zoonotic pathogen.

show abstract

Multi-locus DNA sequencing of Toxoplasma gondii isolated from Brazilian pigs identifies genetically divergent strains

Cited by 34 publications

References 31 publications

Overlapping Toxoplasma gondii Genotypes Circulating in Domestic Animals and Humans in Southeastern Brazil

Overlapping Toxoplasma gondii Genotypes Circulating in Domestic Animals and Humans in Southeastern Brazil

Genetic Characterization of Toxoplasma gondii Revealed Highly Diverse Genotypes for Isolates from Newborns with Congenital Toxoplasmosis in Southeastern Brazil

Population genetics of Toxoplasma gondii: New perspectives from parasite genotypes in wildlife

Contact Info

Product

Resources

About