Clinical and epidemiological aspects of chronic Chagas disease from Southern Brazil

INTRODUCTION

Patients with Chagas disease (CD), caused by Trypanosoma cruzi, present a higher risk of developing other chronic diseases, which may contribute to CD severity. Since CD is underreported in the southern state of Paraná, Brazil, we aimed to characterize clinical and epidemiological aspects of individuals chronically infected with T. cruzi in Southern Brazil.

METHODS

A community hospital-based study was performed, recording clinical/demographic characteristics of 237 patients with CD from Southern Brazil. To estimate the association between different forms of CD and sociodemographic and clinical variables, multiple logistic regression models were built using the Akaike information criterion.

RESULTS

Mean age was 57.5 years and 59% were females. Most patients' (60%) place of origin/birth was within Paraná and they were admitted to the CD outpatient clinic after presenting with cardiac/digestive symptoms (64%). The predominant form of CD was cardiac (53%), followed by indeterminate (36%), and digestive (11%). The main electrocardiographic changes were in the right bundle branch block (39%) and left anterior fascicular block (32%). The average number of comorbidities per patient was 3.9±2.3; systemic arterial hypertension was most common (64%), followed by dyslipidemia (34%) and diabetes (19%); overlapping comorbidities were counted separately. Male sex was associated with symptomatic cardiac CD (OR=2.92; 95%CI: 1.05-8.12; p=0.040).

CONCLUSIONS

This study provided greater understanding of the distribution and clinical profile of CD patients in Southern Brazil, indicating a high prevalence of comorbidities among these patients who are a vulnerable group due to advanced age and substantial risk of morbidity.

Differential ability to resist to complement lysis and invade host cells mediated by MBL in R4 and 860 strains of Trypanosoma cruzi

To produce an infection Trypanosoma cruzi must evade lysis by the complement system. During early stages of infection, the lectin pathway plays an important role in host defense and can be activated by binding of mannan-binding lectin (MBL) to carbohydrates on the surface of pathogens. We hypothesized that MBL has a dual role during parasite-host cell interaction as lectin complement pathway activator and as binding molecule to invade the host cell. We used two polarized strains of T. cruzi, R4 (susceptible) and 860 (resistant) strains, to investigate the role of MBL in complement-mediated lysis. Interestingly R4, but not 860 metacyclic strain, markedly increases the invasion of host cells, suggesting that MBL drives the invasion process while the parasite deactivates the Lectin complement pathway.

Mechanisms of complement lectin pathway activation and resistance by trypanosomatid parasites

Studies in the past decade have demonstrated a crucial role for the complement lectin pathway in host defence against protozoan microbes. Recognition of pathogen surface molecules by mannan-binding lectin and ficolins revealed new mechanisms of innate immune defence and a diversity of parasite strategies of immune evasion. In the present review, we will discuss the current knowledge of: (1) the molecular mechanism of lectin pathway activation by trypanosomes; (2) the mechanisms of complement evasion by trypanosomes; and (3) host genetic deficiencies of complement lectin pathway factors that contribute to infection susceptibility and disease progression. This review will focus on trypanosomatids, the parasites that cause Chagas disease, leishmaniasis and sleeping sickness (African trypanosomiasis).

Functional haplotypes that produce normal ficolin-2 levels protect against clinical leprosy

Host factors have been shown to play a significant role in the susceptibility to and clinical outcome of leprosy. Here, we analyze polymorphisms of the gene encoding ficolin-2 (FCN2), which is a soluble pattern-recognition molecule. A total of 158 patients with leprosy and 210 healthy control subjects from Brazil were investigated. Polymorphisms in the promoter and exon 8 of FCN2 were assessed by DNA sequencing. The distribution of functional FCN2 haplotypes amongpatients was significant different from that among the control subjects (P = .004). These results unveil an immunogenetic role for ficolin-2 in the host response against M. leprae.

A globally occurring indel polymorphism in the promoter of the IFNA2 gene is not associated with severity of malaria but with the positivity rate of HCV

BACKGROUND

Type I Interferons (IFNs) are well known cytokines which exert antiviral activity, antitumor activity and immunomodulatory effects. Single-nucleotide polymorphisms (SNP) and deletions in the gene coding for IFNA2 have been shown to influence the level of expression in vitro. The indel polymorphism -305_-300delAACTTT showed the strongest effect in vitro. To analyse the worldwide distribution of this polymorphism we analyzed five different populations (586 Vietnamese, 199 Central Africans, 265 Brazilians, 108 Kaingang and 98 Guarani). To investigate a possible association with susceptibility to infectious diseases we determined the polymorphism in malaria patients suffering either mild or severe malaria and in a cohort of hepatitis C virus infected individuals.

RESULTS

We could detect the indel polymorphism in all populations analysed. There was no association with this polymorphism and the outcome of malaria but we found an increase of this indel polymorphism in hepatitis C virus positive individuals compared to healthy controls (p = 0.014).

CONCLUSION

Polymorphisms in genes involved in the interferon pathway have been implicated in the resistance or susceptibility against cerebral malaria and HBV. Here we show that an indel polymorphism, which mediates a disadvantageous effect in HBV patients, may also play a disadvantageous role in HCV infections stressing the importance of a fully functional interferon pathway.

Soroepidemiologia da hepatite B e C em índios Kaingang do Sul do Brasil

OBJECTIVE

To investigate the prevalence of infection with hepatitis B virus (HBV) and hepatitis C virus (HCV) among Kaingang Indians living on the Mangueirinha reservation in the state of Paraná, Brazil.

METHODS

The presence of viral markers was investigated in blood samples from 214 volunteers (81 males, 133 females), using immunoenzymatic techniques. The viral markers studied were: antibody to hepatitis B core antigen (anti-HB(c)), antibody to hepatitis B surface antigen (anti-HB(s)), hepatitis B surface antigen (HB(s)Ag), and antibody to hepatitis C virus (anti-HCV). The participants answered a questionnaire on their sociodemographic characteristics, living conditions, personal habits (such as smoking and consuming alcohol or illicit drugs), and history of disease and of vaccination.

RESULTS

The respondents ranged in age from 1 to 90 years; their mean age was 29.85 years. Positivity for anti-HB(s) was 71.02%, and for anti-HB(c) it was 15.42%. None of the individuals was positive for HB(s)Ag. Anti-HCV was detected in only one participant, a 30-year-old woman.

CONCLUSIONS

There were low prevalences of HBV and HCV infection in the Kaingang population studied. The high prevalence of anti-HB(s) in younger individuals indicates good immunization coverage. In the adult population, immunity against HBV was probably acquired mainly by contact with the virus.