Seroepidemiology of Toxoplasma gondii infection in blood donors in a population from the northwestern region of São Paulo state, Brazil.

BACKGROUND: Toxoplasmosis is one of the most common parasitic infections worldwide with varying prevalence between human populations. These variations are mainly associated with human exposure to risk factors. In this article, the seroprevalence of Toxoplasma gondii infection and the risk factors associated with infection in 1729 blood donors from São José do Rio Preto, São Paulo, Brazil were analysed. METHODS: The serological tests for detecting immunoglobulin M (IgM) and immunoglobulin G (IgG) anti-T. gondii were used. The risk factors associated with the infection were identified through the application of an epidemiological questionnaire. RESULTS: The prevalence of T. gondii infection was 48.0%. The following factors were identified in the final model after multiple logistic regression analysis: drinking raw milk (p=0.003; odds ratio [OR] 1.364 [confidence interval {CI} 1.1 to 1.7]), residing in a rural area (p<0.0001; OR 2.764 [CI 1.7 to 4.6]) and receiving a blood transfusion (p=0.015; OR 1.856 [CI 1.1 to 3.0]). CONCLUSIONS: The data obtained in this study showed that the blood donor population is exposed to risk factors related to infection by T. gondii. These data allow the establishment of control programs to contribute to public health in northwestern São Paulo state.

The Potential Contribution of ABO, Lewis and Secretor Histo-Blood Group Carbohydrates in Infection by Toxoplasma gondii.

The glycosyltransferases encoded by genes from the human ABO, Lewis, and Secretor histo-blood group systems synthesize part of the carbohydrate antigens in hematopoietic and non-hematopoietic tissues. The combined action of these glycosyltransferases strongly influences cell, tissue, mucosa, and exocrine secretion carbohydrate phenotypes, including those serving as habitat for mutualistic and pathogenic microorganisms. A set of reports investigated associations between Toxoplasma gondii infection and the ABO histo-blood group system, but the results are contradictory. As T. gondii uses the gastrointestinal tract as a route for infection, and in this organ, the expression of ABO, Lewis, and Secretor histo-blood group carbohydrates occurs, it is reasonable to suppose some biological relationship between them. This text reviewed association studies published in recent decades focusing on the potential contribution of the ABO, Lewis, and Secretor histo-blood group carbohydrates and infection by T. gondii.

FUT3 and FUT2 genotyping and glycoconjugate profile Lewisb as a protective factor to Toxoplasma gondii infection.

The interaction between the ABO, FUT2 and FUT3 genes results in the synthesis of different glycoconjugates profiles expressed in gastrointestinal tract. Moreover, the protozoan Toxoplasma gondii, which causes toxoplasmosis, utilizes this organ as an infection route. We analyzed the frequencies of the different glycoconjugate profiles which were determined by phenotyping ABO and genotyping the status secretor (FUT2; substitution G428A) and Lewis (FUT3; substitution T202C and C314T) histo-blood systems, assessed by PCR-RFLP and PCR-SSP, respectively. A total of 244 pregnant women (G1: Seropositive; G2: Seronegative) for IgG T. gondii antibodies were enrolled. IgG anti-T. gondii antibodies were determined by ELISA. G1 was composed of 158 (64.8%) sample and G2 by 86 (36.2%). The glycoconjugate profile was accessed in 151 seropositive and 85 seronegative samples by the combination of ABO and Lewis phenotyping as well as FUT2 and FUT3 genotyping. In G1, 36 (22.8%) presented the glycoconjugate profile ALeb, 5 (3.3%) A, 13 (8.6) BLeb, 1 (0.6%) B, 41 (27.1%) Leb, 13(8.6%) H, 38(25.2%) Lea and 4 (2.6%) Lec. G2 was composed of 13 (15.3%) of ALeb, 15 (17.6%) BLeb, 1 (1.2%) B, 42 (49,4%) Leb and 14 (16.5) Lea. H and Lec glycoconjugate profiles were not found in G2. The frequencies of the glycoconjugates profiles Leb (p = 0.001) and H (p = 0.005) were significantly different compared between G1 and G2. The glycoconjugate profile H inferred from the ABO phenotyping and FUT3 and FUT2 genotyping is associated with infection by T. gondii in pregnant women and the Leb profile appears to protect the infection by this parasite.

Serum IgG Anti-Toxoplasma gondii Antibody Concentrations Do Not Correlate Nested PCR Results in Blood Donors.

Background:Toxoplasma gondii infects millions of individuals worldwide. This protozoan is food and water-borne transmitted but blood transfusion and organ transplantation constitute alternative forms for transmission. However, the influence of IgG anti-T. gondii antibodies in molecular analysis carried out in peripheral blood still remain unclear. This study aimed to investigate the serum IgG anti-T. gondii antibody concentrations correlate Nested PCR results in blood donors. Methods: 750 blood donors were enrolled. IgM and IgG anti-T. gondii antibodies were assessed by ELISA (DiaSorin, Italy). Nested PCR was performed with primers JW62/JW63 (288 bp) and B22/B23 (115 bp) of the T. gondii B1 gene. The mean values of IgG concentration were compared for PCR positive and PCR Negative blood donors using the t-test or Mann-Whitney according to the normal distribution (p-value ≤ 0.05). Results: 361 (48.1%) blood donors presented positive serology as follow: IgM+/IgG-: 5 (0.6%); IgM+/IgG+: 21 (2.8%); IgM-/IgG+: 335 (44.7%) and 389 (51.9%), negative serology. From 353 blood donors with positive serology tested, the Nested PCR was positive in 38 (10.8%) and negative in 315 (89.2%). There were no differences statistically significant between the mean values of serum IgG anti-T. gondii antibody concentrations and the Nested PCR results. Conclusions: In conclusion, our data show that variations in the serum IgG anti-T. gondii antibody concentrations do not correlate T. gondii parasitemia detected by Nested PCR in chronically infected healthy blood donors.

Evaluation of Serological and Molecular Tests Used for the Identification of Toxoplasma gondii Infection in Patients Treated in an Ophthalmology Clinic of a Public Health Service in São Paulo State, Brazil.

Ocular toxoplasmosis is one of the most common complications caused by the infection with the parasite Toxoplasma gondii. The risk of developing eye lesions and impaired vision is considered higher in Brazil than other countries. The clinical diagnosis is difficult and the use of sensitive and specific laboratorial methods can aid to the correct diagnosis of this infection. We compared serological methods ELISA and ELFA, and molecular cPCR, Nested PCR and qPCR for the diagnosis of T. gondii infection in groups of patients clinically evaluated with ocular diseases non-toxoplasma related (G1 = 185) and with lesions caused by toxoplasmosis (G2 = 164) in an Ophthalmology clinic in Brazil. Results were compared by the Kappa index, and sensitivity (S), specificity (E), positive predictive value (PPV), and negative (NPV) were calculated. Serologic methods were in agreement with ELISA more sensitive and ELFA more specific to characterize the acute and chronic infections while molecular methods were discrepant where qPCR presented higher sensitivity, however, lower specificity when compared to cPCR and Nested PCR.

High genetic diversity in Toxoplasma gondii isolates from pigs at slaughterhouses in Paraíba state, northeastern Brazil: Circulation of new genotypes and Brazilian clonal lineages.

The consumption of raw or undercooked pig meat containing Toxoplasma gondii cysts is an important transmission route of this protozoon to animals and humans. This study aimed to serologically diagnose, isolate and genotype T. gondii from pigs slaughtered for human consumption in the state of Paraíba, northeastern Brazil. Blood and tissue samples (heart, tongue and brain) were collected from 120 pigs at slaughterhouses in the state of Paraíba. Serological examinations were performed with an indirect immunofluorescent antibody test (IFAT) with a cut-off point of 1:64. Tissues from positive animals were subjected to bioassays in mice to isolate the parasite. A total of 12.5% (15/120) of the animals were positive according to the IFAT, with titres ranging from 64 to 2048. Viable parasites were isolated in 80% (12/15) of the bioassays. The twelve T. gondii isolates obtained in this study and an additional 13 previously described isolates were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using 11 genetic markers. Additionally, microsatellite (MS) analysis was performed using 15 markers. Nineteen of the 25 isolates completely genotyped using PCR-RFLP had 12 different genotypes, six of which were newly identified. One isolate had a mixed infection. The same 18 non-mixed isolates had 16 different genotypes based on the MS analysis. Genotype #13 (Caribbean 1), which is commonly encountered in northeastern Brazil and is probably a clonal lineage circulating in this region, was the most frequent genotype detected through both the PCR-RFLP and MS analyses. These results demonstrate that T. gondii is widespread among pigs slaughtered in the state of Paraíba. The results also confirm that this parasite has high genetic diversity in this region and that non-archetypal genotypes commonly circulate between different hosts and across different regions of Brazil.

First report of typical Brazilian Toxoplasma gondii genotypes from isolates of free-range chickens (Gallus gallus domesticus) circulating in the state of Paraíba, Northeast Brazil.

This study evaluated, for the first time, the genetic diversity of Toxoplasma gondii isolates from free-range chickens from the state of Paraíba, Northeast Brazil. Tissue samples from 33 chickens from properties in five municipalities of Paraíba (Esperança, Olho d'Água, Malta, Monteiro, and Patos) were bioassayed in mice. The brains of mice infected with T. gondii cysts were used for DNA extraction and genotyping. Genotyping was performed using 11 PCR-RFLP markers and 15 microsatellite (MS) markers. Complete genotyping results were obtained for 29 isolates, with nine genotypes detected by RFLP and 15 genotypes identified by MS. Three genotypes (#273, #274, and #277) have only been recently identified from pigs in the region. Brazilian clonal types BrII and BrIII were identified from one isolate each. Clonal types I, II, and III were not detected by RFLP. Genotype #13 (Caribbean 1), detected in 48.3% (14/29) of isolates from four of the five municipalities investigated, was the most prevalent genotype in the state of Paraíba. However, the MS analysis showed that of these 14 isolates, only four were unique genotypes, and considering the distance between the municipalities from where they were collected, it is possible that only seven are independent isolates while the others are clones. The other genotypes were restricted to different microregions. The results indicate that the Caribbean 1 lineage of T. gondii is circulating widely in Northeast Brazil. The genotypic diversity of T. gondii in the state of Paraíba is high, and microsatellite analysis revealed this diversity with higher resolution than PCR-RFLP.

Evidence of an association between the O blood group and allergic rhinitis

OBJECTIVE: The aim of this study was to verify if ABO phenotypes are associated with allergic rhinitis. METHODS: 168 patients with allergic rhinitis and 168 control individuals from the same geographical region and paired by gender and age were enrolled in the study. ABO phenotypes were identified in red blood cells using the hemagglutination technique. The Fisher exact and chi-squared tests were employed to compare proportions. Statistical significance was set for an alpha error of 5 percent (p-value < 0.05). RESULTS: The overall differences in the frequencies of the ABO phenotypes of patients and controls were marginal (χ2: 7.569; degrees of freedom (DF): 3; p-value = 0.055) however the O blood group was associated with allergic rhinitis (χ2: 5.764; DF: 1; p-value = 0.016; OR: 1.735; CI 95 percent: 1.127-2.673). The differences in the frequencies of the O phenotype in patients and controls were statistically different for men (χ2: 8.520; DF: 1; p-value = 0.003) but not for women (χ2: 0.6375; DF: 1; p-value = 0.4246). The A phenotype was associated with protection (OR: 0.4385; CI 95 percent: 0.2043-0.9415; p-value = 0.049) and the O phenotype was associated with susceptibility (OR = 2.789; CI 95 percent: 1.385-5.616; p-value = 0.005) to allergic rhinitis only for men. CONCLUSION: The O blood group phenotype is associated with allergic rhinitis in male but not in female patients.

Anti-Toxoplasma gondii antibodies in pregnant women and their newborn infants in the region of São José do Rio Preto, São Paulo, Brazil.

CONTEXT AND OBJECTIVE: Toxoplasmosis transmission during pregnancy can cause severe sequelae in fetuses and newborns. Maternal antibodies may be indicators of risk or immunity. The aim here was to evaluate seropositivity for anti-Toxoplasma gondii (anti-T. gondii) immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies and IgG avidity in pregnant women and their newborn infants. DESIGN AND SETTING: Cross-sectional study in a high-risk pregnancy outpatient clinic. METHODS: Serum samples from pregnant women (n = 87) and their respective newborns (n = 87) were evaluated for anti-T. gondii antibodies using indirect immunofluorescence (IIF) (IgM and IgG), enzyme-linked immunosorbent assay (ELISA) (IgG) and an avidity test. RESULTS: Anti-T. gondii antibodies were identified in 64.4% of the serum samples from the mothers and their infants (56/87). Except for two maternal serum samples (2.3%), all others were negative for anti-T. gondii IgM antibodies, using IIF. The results showed that 92.9% of the pregnant women had high IgG avidity indexes (> 30%) and four samples had avidity indexes between 16 and 30%. Two women in the third trimester of pregnancy were positive for anti-T. gondii IgM antibodies; their babies had avidity indexes between 16 and 30%. The avidity indexes of serum from the other 83 newborns were similar to the results from their mothers. CONCLUSIONS: The results showed that 2% of the pregnant women were at risk of T. gondii transmission during the gestational period. These data seem to reflect the real situation of gestational toxoplasmosis in the northwestern region of the state of São Paulo.

Evidence of an association between the O blood group and allergic rhinitis.

OBJECTIVE: The aim of this study was to verify if ABO phenotypes are associated with allergic rhinitis. METHODS: 168 patients with allergic rhinitis and 168 control individuals from the same geographical region and paired by gender and age were enrolled in the study. ABO phenotypes were identified in red blood cells using the hemagglutination technique. The Fisher exact and chi-squared tests were employed to compare proportions. Statistical significance was set for an alpha error of 5% (p-value < 0.05). RESULTS: The overall differences in the frequencies of the ABO phenotypes of patients and controls were marginal (χ(2): 7.569; degrees of freedom (DF): 3; p-value = 0.055) however the O blood group was associated with allergic rhinitis (χ(2): 5.764; DF: 1; p-value = 0.016; OR: 1.735; CI 95%: 1.127-2.673). The differences in the frequencies of the O phenotype in patients and controls were statistically different for men (χ(2): 8.520; DF: 1; p-value = 0.003) but not for women (χ(2): 0.6375; DF: 1; p-value = 0.4246). The A phenotype was associated with protection (OR: 0.4385; CI 95%: 0.2043-0.9415; p-value = 0.049) and the O phenotype was associated with susceptibility (OR = 2.789; CI 95%: 1.385-5.616; p-value = 0.005) to allergic rhinitis only for men. CONCLUSION: The O blood group phenotype is associated with allergic rhinitis in male but not in female patients.

Anti-Toxoplasma gondii antibodies in pregnant women and their newborn infants in the region of São José do Rio Preto, São Paulo, Brazil / Anticorpos anti-Toxoplasma gondii em gestantes e seus neonatos na região de São José do Rio Preto, São Paulo, Brazil

CONTEXT AND OBJECTIVE: Toxoplasmosis transmission during pregnancy can cause severe sequelae in fetuses and newborns. Maternal antibodies may be indicators of risk or immunity. The aim here was to evaluate seropositivity for anti-Toxoplasma gondii (anti-T. gondii) immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies and IgG avidity in pregnant women and their newborn infants. DESIGN AND SETTING: Cross-sectional study in a high-risk pregnancy outpatient clinic. METHODS: Serum samples from pregnant women (n = 87) and their respective newborns (n = 87) were evaluated for anti-T. gondii antibodies using indirect immunofluorescence (IIF) (IgM and IgG), enzyme-linked immunosorbent assay (ELISA) (IgG) and an avidity test. RESULTS: Anti-T. gondii antibodies were identified in 64.4 percent of the serum samples from the mothers and their infants (56/87). Except for two maternal serum samples (2.3 percent), all others were negative for anti-T. gondii IgM antibodies, using IIF. The results showed that 92.9 percent of the pregnant women had high IgG avidity indexes (> 30 percent) and four samples had avidity indexes between 16 and 30 percent. Two women in the third trimester of pregnancy were positive for anti-T. gondii IgM antibodies; their babies had avidity indexes between 16 and 30 percent. The avidity indexes of serum from the other 83 newborns were similar to the results from their mothers. CONCLUSIONS: The results showed that 2 percent of the pregnant women were at risk of T. gondii transmission during the gestational period. These data seem to reflect the real situation of gestational toxoplasmosis in the northwestern region of the state of São Paulo.

CONTEXTO E OBJETIVOS: A toxoplasmose, quando transmitida durante a gestação, pode causar graves sequelas em fetos e neonatos. Anticorpos maternos podem ser indicadores de risco ou de imunidade. O objetivo foi avaliar a positividade dos anticorpos das classes imunoglobulina M (IgM) e imunoglobulina G (IgG) anti-Toxoplasma gondii (anti-T. gondii), bem como a avidez de IgG em gestantes e seus neonatos. TIPO DE ESTUDO E LOCAL: Estudo transversal em ambulatório de gestação de alto risco. MÉTODOS: Anticorpos anti-T. gondii foram avaliados em amostras de soro de gestantes (n = 87) e seus respectivos neonatos (n = 87) com o uso dos métodos imunofluorescência indireta (IFI) (IgM e IgG), ensaio imunoenzimático (ELISA) (IgG) e avidez. RESULTADOS: Anticorpos anti-T. gondii foram identificados em 64,4 por cento das amostras de soro das mães e seus bebês (56/87). Com exceção de duas amostras de soro materno (2,3 por cento), todas as demais foram negativas anticorpos IgM anti-T. gondii determinado pela IFI. Os resultados mostraram que 92,9 por cento das gestantes tinham índices elevados de avidez de IgG (> 30 por cento) e 4 amostras apresentaram índices de avidez entre 16-30 por cento. Duas gestantes no terceiro trimestre da gravidez eram positivas IgM anti-T. gondii; seus bebês apresentaram índices de avidez entre 16 e 30 por cento. Os índices de avidez dos soros dos outros 83 recém-nascidos foram semelhantes àqueles encontrados nas amostras maternas. CONCLUSÕES: Os resultados mostraram que 2 por cento das gestantes estavam sob risco de transmissão de T. gondii durante o período gestacional. Estes dados parecem refletir a real situação da toxoplasmose gestacional na região noroeste do Estado de São Paulo.