Toxoplasma gondii isolated from a Brazilian patient with rare pulmonary toxoplasmosis has a novel genotype and is closely related to Amazonian isolates.

Pulmonary toxoplasmosis is rare in immunocompetent patients. Herein, a Toxoplasma gondii strain isolated in Brazil from an immunocompetent patient who had severe pulmonary involvement was biologically and molecularly characterized for the first time. The TgHumIMTBr1 isolate was bioassayed in mice showing a virulent phenotype. Restriction fragment length polymorphism (RFLP) genotyping using 11 markers [SAG1, SAG2 (5´3´SAG2 and alt. SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, Apico and CS3] revealed a new non-archetypal genotype assigned as #312. Genotyping using ROP18/ROP5 markers exhibited the virulent combination of alleles 4 and 1. Microsatellite analysis using 15 markers (TUB2, W35, TgM-A, B18, B17, M33, IV.1, X1.1, N60, N82, AA, N61, N83, M48 and M102) revealed an atypical genotype with three unique alleles and a rare combination of alleles 246 (W35) and 203 (TgM-A) that is typical of the Amazon region. Non-archetypal genotypes with unique alleles may function in the occurrence of severe toxoplasmosis in immunocompetent patients in Brazil. Attempts to isolate or molecularly detect T. gondii for further genotyping studies would contribute to the understanding of causes related to the severity of toxoplasmosis in immunocompetent patients.

Typical Brazilian genotype of Toxoplasma gondii isolated from a horse destined for human consumption in Europe from a slaughterhouse.

Toxoplasmosis is a zoonotic disease caused by the protozoan Toxoplasma gondii. Infections occur via the ingestion of oocysts, consumption of cysts containing bradyzoites, and transplacental transmission of tachyzoites. Diversity in T. gondii strains may affect the outcome of clinical toxoplasmosis. The consumption of horse meat is a common practice in some parts of the world. The objectives of the present study were to isolate and genotype T. gondii from horses from an abattoir in the state of Rio Grande do Sul in southern Brazil that exports horse meat to Europe. Antibodies to T. gondii were found in 32.5% (13/40) of the horses using the modified agglutination test (MAT) with a cut-off of 1:25. Tissues from the 13 seropositive horses were bioassayed in mice, and one isolate, designated TgHorseBrRS1, was obtained. PCR-RFLP of the isolate revealed the ToxoDB-RFLP #228 genotype, a typical non-archetypal Brazilian genotype, and microsatellite analysis showed a unique non-archetypal genotype. This study showed that horses from Brazil can harbor viable T. gondii in their tissues, suggesting that recommendations to consumers should be made, especially in European countries where consumption of raw horse meat is common.

Free-range chickens from Santa Catarina state, southern Brazil, as asymptomatic intermediate hosts for Toxoplasma gondii clonal type I and typical Brazilian genotypes.

Chickens are a host that is very resistant to the development of clinical toxoplasmosis. Free-range chickens have been used to indirectly track environmental contamination with Toxoplasma gondii oocysts because they feed on the ground. This study evaluated the genetic diversity of T. gondii isolates from free-range chickens from Florianópolis island in Santa Catarina state, southern Brazil. Sera from 21 chickens were tested for IgG anti-T. gondii antibodies using the modified agglutination test (MAT). Tissue homogenates from the 11 seropositive birds (MAT titres ≥5) were bioassayed in mice. The four obtained isolates (TgCkBrSC1-4) were genotyped using 11 PCR-RFLP markers and 15 microsatellite markers (MS). Four genotypes were identified, three of which are typical Brazilian genotypes (ToxoDB-RFLP #26 and #53 were previously reported and #278 is new), and the other is the rare clonal type I genotype. This type I isolate was considered a variant according to MS analysis, with two atypical alleles, which emphasizes the genetic diversity of the parasite in Brazil. The genetic variability of T. gondii in South America may be related to the high occurrence of severe ocular and congenital toxoplasmosis in humans in this region. High human seroprevalence and frequency of ocular toxoplasmosis are reported in southern Brazil, but there is limited information on the T. gondii strains that are circulating in this region, so more studies should be conducted to identify the strains in different hosts and in human toxoplasmosis cases.

Molecular diagnosis of symptomatic toxoplasmosis: a 9-year retrospective and prospective study in a referral laboratory in São Paulo, Brazil

ABSTRACT Symptomatic forms of toxoplasmosis are a serious public health problem and occur in around 10-20% of the infected people. Aiming to improve the molecular diagnosis of symptomatic toxoplasmosis in Brazilian patients, this study evaluated the performance of real time PCR testing two primer sets (B1 and REP-529) in detecting Toxoplasma gondii DNA. The methodology was assayed in 807 clinical samples with known clinical diagnosis, ELISA, and conventional PCR results in a 9-year period. All samples were from patients with clinical suspicion of several features of toxoplasmosis. According to the minimum detection limit curve (in CT), REP-529 had greater sensitivity to detect T. gondii DNA than B1. Both primer sets were retrospectively evaluated using 515 DNA from different clinical samples. The 122 patients without toxoplasmosis provided high specificity (REP-529, 99.2% and B1, 100%). From the 393 samples with positive ELISA, 146 had clinical diagnosis of toxoplasmosis and positive conventional PCR. REP-529 and B1 sensitivities were 95.9% and 83.6%, respectively. Comparison of REP-529 and B1 performances was further analyzed prospectively in 292 samples. Thus, from a total of 807 DNA analyzed, 217 (26.89%) had positive PCR with, at least one primer set and symptomatic toxoplasmosis confirmed by clinical diagnosis. REP-529 was positive in 97.23%, whereas B1 amplified only 78.80%. After comparing several samples in a Brazilian referral laboratory, this study concluded that REP-529 primer set had better performance than B1 one. These observations were based after using cases with defined clinical diagnosis, ELISA, and conventional PCR.

Evaluation of serological and molecular tests used to identify Toxoplasma gondii infection in pregnant women attended in a public health service in São Paulo state, Brazil.

Toxoplasmosis during pregnancy can have severe consequences. The use of sensitive and specific serological and molecular methods is extremely important for the correct diagnosis of the disease. We compared the ELISA and ELFA serological methods, conventional PCR (cPCR), Nested PCR and quantitative PCR (qPCR) in the diagnosis of Toxoplasma gondii infection in pregnant women without clinical suspicion of toxoplasmosis (G1=94) and with clinical suspicion of toxoplasmosis (G2=53). The results were compared using the Kappa index, and the sensitivity, specificity, positive predictive value and negative predictive value were calculated. The results of the serological methods showed concordance between the ELISA and ELFA methods even though ELFA identified more positive cases than ELISA. Molecular methods were discrepant with cPCR using B22/23 primers having greater sensitivity and lower specificity compared to the other molecular methods.

Anti-Toxoplasma gondii antibodies in patients with beta-hemoglobinopathies: the first report in the Americas.

BACKGROUND: In Brazil, there have been no previous studies of Toxoplasma gondii infection in sickle cell anemia patients and carriers of severe forms of beta-thalassemia. This study evaluated T. gondii infection in patients with beta-hemoglobinopathies. METHODS: A total of 158 samples, 77 (48.7%) men and 81 (51.3%) women, were evaluated. Three groups were formed: G1 (85 patients with sickle cell disease); G2 (11 patients with homozygous beta-thalassemia; G3 (62 patients with heterozygous beta-thalassemia). ELISA was employed to identify anti-T. gondii IgM and IgG antibodies, and molecular analysis was performed to determine beta-hemoglobin mutations. Fisher's exact test was used to compare frequencies of anti-T. gondii IgM and IgG antibodies in respect to gender and age. RESULTS: Anti-T. gondii IgG antibodies were found in 43.5% of individuals in G1, 18.1% in G2 and 50% in G3. All samples from G1 and G2 were seronegative for anti-T. gondii IgM antibodies, but 3.2% from G3 were seropositive. Considering anti-T. gondii IgG antibodies, no statistical significant differences were found between these groups nor in seroprevalence between genders within each group. Despite this, comparisons of the mean ages between G1, G2 and G3 were statistically significant (G2 vs. G1: p value = 0.0001; G3 vs. G1: p-value <0.0001; G3 vs. G2: p-value = 0.0001). CONCLUSION: A comparison by age of patients with sickle cell anemia showed a trend of lower risk of infection among younger individuals. Therefore, this study demonstrates that T. gondii infection occurs in patients with beta-thalassemia and sickle cell anemia in Brazil as seen by the presence of anti-T. gondii IgM and IgG antibodies.

Frequency of anti- Toxoplasma gondii IgA, IgM, and IgG antibodies in high-risk pregnancies, in Brazil.

INTRODUCTION: Toxoplasmosis during pregnancy can be severe; thus, it is essential to diagnose the disease via serological tests. METHODS: An enzyme-linked immunosorbent assay (ELISA) was used to investigate anti-Toxoplasma gondii immunoglobulin A (IgA), M (IgM) and G (IgG) antibodies in 62 high-risk pregnant women. RESULTS: Forty-three (69.4%) women were positive for IgA, 31 (50%) for IgG, and 57 (91.9%) for IgM; 4 (6,5%) were positive for IgA but negative for IgM; 10 (16.1%) were negative for IgA and IgM but positive for IgG. CONCLUSIONS: Testing for these antibodies can help diagnose infection in pregnant women, thereby contributing to clinical management.