Biologic and genetic comparison of Toxoplasma gondii isolates in free-range chickens from the northern Pará state and the southern state Rio Grande do Sul, Brazil revealed highly diverse and distinct parasite populations

Dubey, J. P.; Natarajan, Sundar; Gennari, Solange Maria; Minervino, Antônio Humberto Hamad; Farias, Nara Amélia da Rosa; Ruas, Jerônimo Lopes; Santos, Tânia Regina Bettin dos; Cavalcante, Guacyara Tenório; Kwok, O. C. H.; Su, Chunlei

doi:10.1016/j.vetpar.2006.08.024

Cited by 159 publications

(106 citation statements)

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“…Forty four isolates killed all T. gondii infected mice between 10 and 30 days p.i., corroborating other studies that show that most isolates from the mainland Brazil are mouse virulent (Dubey et al, 2007;Pena et al, 2008;Ragozo et al, 2008). It has to be pointed out that mouse virulence depends on several factors including the stage of the parasite, route, dose, types of mice used, and the strain of the parasite.…”

Section: Discussionsupporting

confidence: 85%

“…Espírito Santo of the strains prevalent in the environment, as FR chickens become infected mostly by feeding from soil contaminated with oocysts (Ruiz and Frenkel, 1980). In the last 12 years we and others have determined prevalence of T. gondii in FR chickens from different regions of Brazil (Peixoto and Lopes, 1990;Garcia et al, 2000;Dubey et al, 2002;da Silva et al, 2003;Dubey et al, 2003a,b;Brandão et al, 2006;Dubey et al, 2006Dubey et al, , 2007Aigner et al, 2010;de Oliveira et al, 2009;Soares et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Seroprevalence and isolation of Toxoplasma gondii from free-range chickens from Espírito Santo state, southeastern Brazil

Beltrame

Pena

Ton

et al. 2012

Veterinary Parasitology

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Seroprevalence and isolation of Toxoplasma gondii from free-range chickens from Espírito Santo state, southeastern Brazil

Beltrame

Pena

Ton

et al. 2012

Veterinary Parasitology

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“…The relative frequency of animals positive for T. gondii of all farms valued between 40 and 100%. The results of this study showed a high frequency of animals positive for T. gondii by MAT, which agrees with other ϐin-dings in surveys conducted in Brazil (Dubey et al 2006a, 2007a, De Oliveira et al 2009). …”

Section: Resultssupporting

confidence: 91%

Serologic and molecular diagnostic and bioassay in mice for detection of Toxoplasma gondii in free ranges chickens from Pantanal of Mato Grosso do Sul

et al. 2012

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The aim of this study was to investigate the occurrence of Toxoplasma gondii and compare the results obtained in the Modiϐied Agglutination Test (MAT), Polimerase Chain Reaction (PCR) and bioassay in mice. In order to accomplish this, 40 free-range chickens from eight farms in neighboring areas to the Pantanal in Nhecolândia, Mato Grosso do Sul, were euthanized and blood samples, brain and heart were collected. The occurrence of anti-T. gondii antibodies found in chickens was 67.5% (27 samples), considering as a cutoff point the dilution 1:5. Among the samples analyzed, 7 (25.9%) were positive in the dilution 1:5, 3 (11.1%) in 1:10, 2 (7.4%) in 1:20, 3 (11.1%) in 1:320, 1 ( 3.7%) in 1:640, 3 (11.1%) in 1:1280, 2 (7.4%) in 1:2560, 4 (14.8%) in 1:5120 and 2 (7.4%) in 1:10.240. From the mixture of tissue samples (brain and heart) from the chickens analyzed, 16 (40%) presented electrophoretic bands compatible with T. gondii by PCR (gene B1). In the comparison of techniques, 59.26% positivity in PCR was revealed among animals that were seropositive in MAT (cutoff 1:5). From 141 inoculated mice, six (4.44%) died of acute toxoplasmosis between 15 and 23 days after inoculation. Surviving mice were sacriϐiced at 74 days after inoculation, and a total of 28 cysts were found in the brains of 10 distinct groups. From the seropositive hens, 27 bioassays were performed and 11 (40.7%) isolates were obtained. A greater number of isolations happened in mice that were inoculated with tissues from chickens that had high titers for anti-T. gondii antibodies. Chronic infection in mice was observed in nine groups (33.3%) from ϐive different properties. Among the surviving mice, 25.6% were positive for T. gondii in MAT (1:25). From mice positive in PCR, 87.5% were also positive in MAT. Among the PCR-negative mice, 5.2% were positive for T. gondii in MAT. It can be concluded through this study that the occurrence of infecton by T. gondii in the rural properties studied was high, that PCR directed to gene B1 does not conϐirm the viability of the parasite, but it can be used as a screening method for the selection of chickens infected by T. gondii, that the animals with titer greater than 10 must be prioritized for the selection of animals for bioassay, since for them, the chances of isolating the parasite are greater and that seroconversion in experimentally infected mice is not a good indicator for isolating the agent.

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“…Although type II isolates have been found in Chile , it seems very rare elsewhere in South America. Genetically distinct isolates are found in different regions of South America (Dubey et al, 2007c). Common clonal lineages, different from the three classical types, may circulate on this continent (Pena et al, 2007).…”

Section: South Americamentioning

confidence: 99%

Toxoplasma gondii, “new” genotypes and virulence

Dardé¹

2008

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144

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Summary :Toxoplasma gondii has been described as a parasite with a low genetic diversity and a clonal population structure. The three main clonal lineages designated as type I, II or III largely predominate in Europe and North America. But strains not related to these main lineages circulate, notably, in other continents. They possess a shuffled combination of alleles that typify the three clonal types and unique polymorphisms detected by multilocus analysis. The population structure of Toxoplasma in these continents is also characterized by a higher genetic diversity associated with a lower linkage desequilibrium suggesting a role for genetic exchange. Due to their genomic diversity, it is difficult to draw global conclusions about their virulence. However, most of them are virulent in mice at isolation. Several reports also suggest a higher pathogenicity in humans and an association with ocular toxoplasmosis or severe cases of acquired toxoplasmosis in immunocompetent patients. T he three main types respond to the criteria for a clonal population structure of Toxoplasma (isolation of identical multilocus genotypes over large geographic areas and at interval of several years, and a strong linkage disequilibrium) (Tibayrenc et al., 1991). This simple clonal structure is accompanied by a low genetic divergence between the three main lineages (only ≈ 2 % divergence at the DNA sequence level between lineages). A large majority (84 %) of the of the single nucleotide polymorphisms (SNPs) identified among the three types are type I and II SNPs, type III polymorphisms (only 16 %) being located mainly on chromosome IV (Boyle et al., 2006). The assymetrical distribution of SNPs on chromosomes indicates that types I and III are second and first generation offspring, respectively, of a cross between a type II strain and one of two ancestral strains. The limited genetic diversity within each of these lineages and the low divergence between lineages strongly suggest that these three clonal lineages have expanded as the dominant strains relatively recently, from a common ancestor 10,000 years ago (Su et al., 2003).

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Biologic and genetic comparison of Toxoplasma gondii isolates in free-range chickens from the northern Pará state and the southern state Rio Grande do Sul, Brazil revealed highly diverse and distinct parasite populations

Cited by 159 publications

References 21 publications

Seroprevalence and isolation of Toxoplasma gondii from free-range chickens from Espírito Santo state, southeastern Brazil

Seroprevalence and isolation of Toxoplasma gondii from free-range chickens from Espírito Santo state, southeastern Brazil

Serologic and molecular diagnostic and bioassay in mice for detection of Toxoplasma gondii in free ranges chickens from Pantanal of Mato Grosso do Sul

Toxoplasma gondii, “new” genotypes and virulence

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