Introduction: This study assessed the seroprevalence of cytomegalovirus, associated factors, and Epstein-Barr virus coinfection among adult residents of Manaus. Methods: Using a cross-sectional study design, we collected blood samples from 136 individuals in a household survey in 2016. Prevalence ratios were calculated using Poisson regression. Results: Cytomegalovirus and Epstein-Barr virus seroprevalences were 67.6% (95% CI: 9.7-75.6%) and 97.8% (95% CI: 95.3-100.0%), respectively. Coinfection was observed in 66.2% (95% CI: 58.1-74.2%) of participants. Bivariate analysis showed no statistical association. Conclusions: Seroprevalences were high among participants and approximately 7 out of 10 individuals had cytomegalovirus and Epstein-Barr virus coinfection.

The COVID-19 pandemic threatens indigenous peoples living in suburban areas of large Brazilian cities and has thus far intensified their pre-existing socio-economic inequalities. We evaluated the epidemiological situation of SARS-CoV-2 infection among residents of the biggest urban multiethnic indigenous community of the Amazonas state, Brazil. Blood samples of 280 indigenous people living in the surrounding area of Manaus were tested for the presence of anti-SARS-CoV-2 IgA or IgG antibodies. The risk factors and sociodemographic information were assessed through an epidemiological questionnaire. We found a total positivity rate of 64.64% (95% CI 59.01–70.28) for SARS-CoV-2 infection. IgA and IgG were detected in 55.71% (95% CI 49.89–61.54) and 60.71% (95% CI 54.98–66.45) of the individuals, respectively. Over 80% of positive individuals were positive for both IgA and IgG.No significant difference in positivity rates between genders or age groups was observed. Moreover, the age group ≥ 60 years old showed the highest antibody ratios (IgA mean ratio = 3.080 ± 1.623; IgG mean ratio = 4.221 ± 1.832), while the age groups 13–19 and 20–29 showed the lowest IgA (mean ratio = 2.268 ± 0.919) and IgG ratios (mean ratio = 2.207 ± 1.246), respectively. Individuals leaving the home more frequently were at higher risk of infection (Odds ratio (OD) 2.61; 95% CI 1.00–1.49; p = 0.048). Five or more individuals per household increased fivefold the risk of virus transmission (OR 2.56; 95% CI 1.09–6.01; p = 0.019). The disproportionate dissemination of SARS-CoV-2 infection observed among the study population might be driven by typical cultural behavior and socioeconomic inequalities. Despite the pandemic threat, this population is not being targeted by public policies and appears to be chronically invisible to the Brazilian authorities.

Cytomegalovirus (CMV) is a worldwide distributed pathogen that may cause serious complications in patients with hematological diseases. This study aimed to serologically characterize CMV infection in patients suffering from hematological diseases in Amazonas state, Brazil. Serum samples from 323 patients were tested for the presence of anti-CMV IgM or IgG antibodies using an enzyme-linked immunosorbent assay. Positive samples for IgM were submitted to the IgG avidity test to differentiate primary infection from recurrent infection. An epidemiological questionnaire was administered to collect the sociodemographic information of the study population. The overall prevalence of CMV infection verified in this study was 91.3%. The highest rates were found in patients suffering from platelet disorders (94.5%), anemia (93.3%), or leukemia (91%). The study population was predominantly composed of individuals with low socioeconomic status. Blood transfusions were more common in patients with anemia or leukemia, but this variable was not correlated with the seropositivity for CMV infection. Measurement of IgG avidity in patients positive for anti-CMV IgM demonstrated a recurrent infection rate of 5.2% (17/323). Over 80% of recurrent infections occurred in patients with acute lymphocytic leukemia (ALL) or anemia. Our findings indicated that CMV infection is highly prevalent in patients from the western Brazilian Amazon who have hematological diseases. The prevalence observed progressively rose with increasing age, whereas anemia or ALL figured as risk factors for the recurrence of CMV infection.

The systemic inflammatory response elicited by acute Zika virus (ZIKV) infection during pregnancy plays a key role in the clinical outcomes in mothers and congenitally infected offspring. The present study aimed to evaluate the serum levels of GDF-3 and inflammasome-related markers in pregnant women during acute ZIKV infection. Serum samples from pregnant (n = 18) and non-pregnant (n = 22) women with acute ZIKV infection were assessed for NLRP3, IL-1β, IL-18, and GDF3 markers through an enzyme-linked immunosorbent assay. ZIKV-negative pregnant (n = 18) and non-pregnant women (n = 15) were used as control groups. All serum markers were highly elevated in the ZIKV-infected groups in comparison with control groups (p < 0.0001). Among the ZIKV-infected groups, the serum markers were significantly augmented in the pregnant women in comparison with non-pregnant women (NLRP3 p < 0.001; IL-1β, IL-18, and GDF3 p < 0.0001). The IL-18 marker was found at significantly higher levels (p < 0.05) in the third trimester of pregnancy. Bivariate and multivariate analyses showed a strong positive correlation between GDF3 and NLRP3 markers among ZIKV-infected pregnant women (r = 0.91, p < 0.0001). The findings indicated that acute ZIKV infection during pregnancy induces the overexpression of GDF-3 and inflammasome-related markers, which may contribute to congenital disorders and harmful pregnancy outcomes.

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