Predictor Variables in the Spread of Chagas Disease in Rural Areas.

Over a hundred years ago after the discovery of Chagas disease (CD) in Brazil, the World Health Organization estimates a number of 6 to 7 million people infected by Trypanosoma cruzi worldwide. Therefore, the goal of this work was to identify variables related to the spread of infection by T. cruzi in humans living in rural areas, seeking predictor variables. A systematic review of the literature has been conducted, with a search in the Scopus platform, using the search string "Chagas disease" and "rural", resulting in 85 valid and analyzed scientific studies (1977 and 2022). Twenty-seven predictor variables have been acquired, and 19 of them have been grouped, such as: socioeconomic and educational, housing, environmental, sanitary, and cultural; and 8 variables related to T. cruzi seropositive individuals. The predictor variables yielded significant results (p-value < 0.05) in 59.5% of the cases (195/328), with a median of 66.7%. In other words, studies relating to 50% of the 27 variables showed significance equal to or greater than 66.7% of the time. The independent variables with the highest proportion of significant data (p-value < 0.05) were Education (87.6%), Intradomicile building (70%), Domestic animals (69.6%), and Triatomines (69.2%) in the households. Some variables reached 100%; however, few articles were found, indicating the need for further research, especially for Sanitation and Culture. It has been concluded that, in the several contexts found, the social vulnerability and lack of information led the individual to living in environments where inhabitability is inadequate, to perform limited work activity and develop habits and behaviors which impair them in an environmental insalubrity situation, favorable to the access of vectors and pathogens of anthropozoonoses such as CD.

Risk of adverse pregnancy and infant outcomes associated with prenatal Zika virus infection: a post-epidemic cohort in Central-West Brazil.

This study aimed to estimate the risks of adverse infant outcomes in the first year of life related to prenatal Zika virus (ZIKV) exposure. A prospective cohort of pregnant women with rash was recruited in Central-West Brazil in a post-epidemic period (January 2017 to April 2019). We evaluated participants' medical histories and performed ZIKV diagnostic testing using molecular (reverse transcription polymerase chain reaction [RT-PCR]) and serologic (immunoglobulin [Ig]M and plaque reduction neutralization tests [PRNT90]) assays. The ZIKV-positive group included both RT-PCR-confirmed cases as well as IgM and/or PRNT90-positive probable cases. Children were evaluated at birth and in the first 12 months of life. Transfontanellar ultrasound, central nervous system computed tomography, eye fundoscopy and retinography were performed. We estimated the absolute risk and 95% confidence interval (95% CI) of adverse infant outcomes among confirmed prenatally ZIKV-exposed children. Among 81 pregnant women with rash, 43 (53.1%) were ZIKV infected. The absolute risk of microcephaly among offspring of ZIKV-infected pregnant women was 7.0% (95% CI: 1.5-19.1), including the two cases of microcephaly detected prenatally and one detected postnatally. In total, 54.5% (95% CI: 39.8-68.7) of children in the ZIKV-exposed group had at least one ophthalmic abnormality, with the most frequent abnormalities being focal pigmentary mottling and chorioretinal atrophy or scarring. Our findings reinforce the importance of long-term monitoring of prenatally ZIKV-exposed children born apparently asymptomatic for Congenital Zika Syndrome.

High frequency of pre-existing neutralizing antibody responses in patients with dengue during an outbreak in Central Brazil.

BACKGROUND: This study aims to identify dengue neutralizing antibody response in patients with dengue from a well-characterized cohort during an outbreak in central Brazil, 2012-2013. METHODS: We analyzed paired samples from 40 patients with severe dengue and 20 patients with dengue. Eligibility criteria were: IgM, NS1Ag and/or RT-PCR positivity and positive IgG result. Plaque reduction neutralization test (PRNT50) from DENV-1 to DENV-4 was performed to identify serotype-specific NAbs response. An infecting serotype was defined as ≥4-fold increase in DENV NAbs in paired samples. Monotypic response was classified as PRNT50 ≥ 1/20 to only one DENV serotype, and multitypic response was considered to be PRNT50 ≥ 1/20 to two or more serotypes simultaneously. RESULTS: Patients were mainly adults. Virological dengue infection was confirmed by RT-PCR: DENV-4(n = 14) and DENV-1(n = 10). Forty-four out of 60(73.3 %) patients had NAbs to DENV-4, DENV-1(68.3 %), DENV-2(68.3 %) and DENV-3(61.6 %) respectively. Fifteen percent of the cases presented monotypic response, whereas 85 % had multitypic response. DENV-4 infected-patients presented the greatest difference in PRNT50 titers compared with other serotypes. Pre-existing DENV NAbs was not correlated with disease severity. This was the first time that DENV-4 was implicated in an epidemic in the region. CONCLUSION: Our data indicates high exposure of multiple DENV serotypes in all age groups in the pre-dengue vaccine era and also previous to Zika virus introduction in Brazil.

Evaluation of a commercial real-time PCR kit for detection of dengue virus in samples collected during an outbreak in Goiania, Central Brazil, in 2005.

In the past 2 decades, dengue has reemerged in Brazil as a significant public health problem. Clinicians demand a diagnostic test with high sensitivity that is applicable during the early symptomatic phase. We aimed to test two distinct molecular methods on samples from suspected dengue cases during an outbreak in Central Brazil. Acute-phase serum specimens from 254 patients suspected of having dengue were collected during 2005 in the city of Goiânia, Central Brazil. Samples were blindly evaluated by real-time and multiplex PCR in addition to routine immunoglobulin M serology and virus culture. Overall, acute dengue was confirmed by serology, multiplex PCR, or virus isolation for 80% of patients (203/254). Another four patients presented real-time PCR-positive results as the unique marker of dengue. Higher real-time PCR positivity levels and viral loads were observed in the early symptomatic phase of disease (< or =5 days) than after this period. Multiplex and real-time PCR assays presented a high kappa agreement (0.85). According to multiplex PCR, 60 samples harbored dengue virus type 3 (DEN-3), 4 samples harbored DEN-2, and 1 sample displayed a pattern compatible with a double infection with DEN-2 and -3. The dengue virus real-time kit was found to be practical and adjustable for high throughput, to display the best performance in the early symptomatic phase of dengue cases, and to be valuable for confirming dengue diagnosis in a timely manner.