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.

Genetic polymorphisms related to the vitamin D pathway in patients with cirrhosis with or without hepatocellular carcinoma (HCC).

Objective: To evaluate the association of genetic polymorphisms of vitamin D transporter protein (DBPrs4588 and DBP-rs7041) and cytochrome P450-24A1 (CYP24A1-rs6013897) in patients with cirrhosis with or without hepatocellular carcinoma (HCC), including demographic/clinical/biochemical profiles. Methods: A total of 383 individuals were studied, considering the total group (TotalG) of patients with cirrhosis (TotalG: N = 158) with or without HCC, distributed into Group 1 (G1): cirrhosis and HCC; Group 2 (G2): isolated cirrhosis; and 225 individuals without hepatopathies (G3). Polymorphisms were analysed by real-time polymerase chain reaction. An alpha error of 5% was admitted. Results: CYP24A1-rs6013897 predominated the genotype with at least one polymorphic allele (_/T) in G1 (98.3%) versus G2 (88.8%; p = 0.0309). There was a moderate positive correlation between vitamin D and parathyroid hormone in patients (TotalG: R 2 = 0.3273). Smoking, alcoholism and diabetes mellitus (DM) stood out as independent factors for cirrhosis, as well as for cirrhosis with HCC, except for smoking, adding, in this case, advanced age, male gender, polymorphic allele of CYP24A1-rs6013897, viral hepatitis and high levels of serum gamma-glutamyl transferase (GGT), alpha-fetoprotein (AFP) and creatinine. An increase in survival was observed in the presence of the polymorphic allele of DBP-rs7041 (p = 0.0282). Conclusion: CYP24A1-rs6013897 is associated with cirrhosis and HCC as a predictor, while DBP-rs4588 is associated with reduced vitamin D, and DBP-rs7041 provides increased survival, suggesting a protective characteristic. Advanced age, alcoholism, DM, viral hepatitis and high levels of GGT, AFP and creatinine are also confirmed as predictors of HCC and cirrhosis, while smoking, alcoholism and DM for isolated cirrhosis only.

TNFα rs1799964 TT genotype may be a susceptibility factor for vertical transmission of Toxoplasma gondii and clinical signs in newborns from pregnant women with acute toxoplasmosis.

BACKGROUND: One of the main impacts of Toxoplasma gondii infection occurs during pregnancy and is related to the vertical transmission of the parasite (congenital toxoplasmosis), which can cause severe clinical outcomes and fetal death. During acute infection, in order to control the rapid replication of tachyzoites, different host immune response genes are activated, and these include cytokine-encoding genes. Considering that polymorphisms in cytokine genes may increase susceptibility to vertical transmission of T. gondii by determining the immune status of the pregnant woman, this study evaluated the influence of polymorphisms of tumor necrosis factor alpha (TNFα) rs1799964 (- 1031) and interleukin 1 beta (IL1ß) rs16944 (- 511) genes on gestational toxoplasmosis and on the vertical transmission of the parasite and verified the allele and genotype frequency of these polymorphisms in pregnant patients whose respective newborn did or did not present clinical abnormalities suggestive of congenital toxoplasmosis. METHODS AND RESULTS: A total of 204 pregnant patients with (n = 114) or without (n = 90) infection by T. gondii were enrolled. No associations were found involving the polymorphisms rs1799964 (- 1031) of the TNFα gene and rs16944 (- 511) of the IL1ß gene with the increased chance of T. gondii infection during pregnancy. However, it was observed that the maternal TT genotype referring to the polymorphism of the TNFα gene seems to influence the vertical transmission of the parasite (P = 0.01; χ2 = 6.05) and the presence of clinical manifestation in newborns from pregnancies with acute toxoplasmosis (P = 0.007; χ2 = 9.68). CONCLUSION: The TNFα rs1799964 TT genotype may act as a susceptibility factor for the vertical transmission of parasite and for the presence of clinical signs in newborns from pregnant women with acute toxoplasmosis.

The Role of microRNAs in the Infection by T. gondii in Humans.

MicroRNAs are molecules belonging to an evolutionarily conserved family of small non-coding RNAs, which act on post-transcriptional gene regulation, causing messenger RNA (mRNA) degradation or inhibiting mRNA translation into proteins. These molecules represent potential biomarkers for diagnosis, non-invasive prognosis, and monitoring the development of the disease. Moreover, they may provide additional information on the pathophysiology of parasitic infections and guide strategies for treatment. The Apicomplexan parasite Toxoplasma gondii modifies the levels of microRNAs and mRNAs in infected host cells by modulating the innate and adaptive immune responses, facilitating its survival within the host. Some studies have shown that microRNAs are promising molecular markers for developing diagnostic tools for human toxoplasmosis. MicroRNAs can be detected in human specimens collected using non-invasive procedures. changes in the circulating host microRNAs have been associated with T. gondii infection in mice and ocular toxoplasmosis in humans. Besides, microRNAs can be amplified from samples using sensitive and molecular-specific approaches such as real-time PCR. This review presents recent findings of the role that microRNAs play during T. gondii infection and discuss their potential use of these small nuclei acid molecules to different approaches such as laboratory diagnosis, modulation of cell and tissue infected as other potential applications in human toxoplasmosis.