Validation of a New Duplex Real-Time Polymerase Chain Reaction for Chlamydia trachomatis DNA Detection in Ocular Swab Samples.

Trachoma is the world-leading infectious cause of preventable blindness and is caused by the bacteria Chlamydia trachomatis. In developing countries, diagnosis is usually based on clinical evaluation. Serological-based tests are cheaper than molecular-based ones, but the latter are more sensitive and specific. The present study developed a new duplex qPCR which concomitantly detects the C. trachomatis cryptic plasmid and the human 18S rRNA gene, with an LOD95% for C. trachomatis DNA of 13.04 genome equivalents per reaction. The new qPCR was tested using 50 samples from an endemic area and 12 from a non-endemic area that were previously characterized using direct immunofluorescence assay (DFA) and clinical evaluation. Among the 50 endemic samples, 3 were found to be positive by clinical evaluation (6%), 18 were found to be positive by DFA (36%), and 48 were found to be positive by qPCR (96%). Next, the new duplex qPCR was validated using 50 samples previously characterized by qPCR. Validation was carried out on a benchtop instrument (ABI7500) or on a portable point-of-care instrument (Q3-Plus), showing 95% specificity and 100% sensitivity. The ubiquitous presence of C. trachomatis DNA in samples from the endemic region confirms that constant monitoring is of paramount importance for the effective measurement of the elimination of trachoma. The newly developed duplex qPCR presented in this study, along with its validation in a portable qPCR system, constitutes important tools toward achieving this goal.

Genome sequencing of dengue virus serotype 4 in a bat brain sample (Platyrrhinus helleri) from the Brazilian Amazon.

The existence of sylvatic transmission of dengue virus in communities of neotropical bats remains uncertain. In this work we present a near-complete genome of dengue virus serotype 4 obtained from the brain sample of a bat from Platyrrhinus helleri specie collected in the Brazilian Amazon region. The presence of the virus in the brain sample may indicate a possible tropism for the central nervous system in bats, which may justify negative results in previous studies that focused on analysis of other tissues, such as liver and spleen. Besides the duration of dengue virus circulation in the Americas (circa 40 years) may be too short for an implementation of a sylvatic dengue virus cycle. Our findings suggest that continued monitoring is needed to confirm with the neotropical bats could potentially act as a natural reservoir of dengue in the region.

Epidemiology and control of trachoma in the state of Ceará, Northeast Brazil, 2007-2021.

BACKGROUND: To analyze the epidemiology, surveillance, and control strategies for trachoma in the state of Ceará, northeast Brazil, from 2007 to 2021. METHODS: This ecological study was based on secondary data from the Information System on Notifiable Diseases of the Secretary of Health of the state of Ceará. Data from school and home surveys for trachoma detection obtained during the study period were analyzed, the percentage of positivity was estimated, and sociodemographic and clinico-epidemiological factors were investigated. RESULTS: The coverage of trachoma surveillance and control actions in Ceará municipalities increased from 12.5% in 2007 to 55.9% in 2019, but with an average restriction of 8.0% during the COVID-19 pandemic. The estimated trachoma positivity (mean overall positivity) was less than 5.0% (2.76%, 95% CI 1.2-5.2), with a higher proportion of cases in the 5-9-year age group (45.0%, 95% CI 44.6-45.4), in females (53.2%, 95% CI 52.8-53.6), and rural areas (52.6%, 95% CI 52.2-53.0). Positivity above 10.0% was observed in the Litoral Leste/Jaguaribe and Sertão Central regions, with a higher occurrence of the follicular inflammatory clinical form (98.1%, 95% CI 98.0-98.2). CONCLUSIONS: Trachoma remains in the state of Ceará and is likely underreported. Despite recent advances, the fragility of health surveillance activities compromises the recognition of the actual magnitude and distribution of trachoma in the state. Accurate information is fundamental for planning, monitoring, and evaluating surveillance and disease control.

Assessment of the Accuracy, Usability and Acceptability of a Rapid Test for the Simultaneous Diagnosis of Syphilis and HIV Infection in a Real-Life Scenario in the Amazon Region, Brazil.

We field-assessed the accuracy, acceptability, and feasibility of the SD BIOLINE HIV/Syphilis Duo rapid diagnostic test in three groups: pregnant women, female sex workers (FSW), and men who have sex with men (MSM). Venous blood samples collected in the field were compared with the respective gold standard methods: SD BIOLINE HIV/Syphilis Duo Treponemal Test versus FTA-abs (Wama brand) treponemal laboratory test for syphilis, and SD BIOLINE HIV/Syphilis Duo Test versus the fourth generation Genscreen Ultra HIV Ag-Ag (Bio-Rad brand) laboratory test for HIV. From a total of 529 participants, 397 (75.1%) were pregnant women, 76 (14.3%) FSW and 56 (10.6%) MSM. Sensitivity and specificity parameters of HIV were 100.0% (95% CI: 82.35-100.0%) and 100.0% (95% CI: 99.28-100.0%), respectively. Sensitivity and specificity parameters found for TP antibody detection were 95.00% (95% CI: 87.69-98.62%) and 100.0% (95% CI: 98.18-100.0%), respectively. The SD BIOLINE HIV/Syphilis Duo Test showed high acceptability among participants (85.87%) and health professionals (85.51%), as well as easy usability by professionals (91.06%). The usability of the SD BIOLINE HIV/Syphilis Duo Test kit would not be a barrier to accessing rapid testing, if the product were incorporated into the list of health service supplies.

Prevalence of trachoma in the non-indigenous Baixo Jaguaribe micro-region, Ceará State, Northeast Brazil.

BACKGROUND: The aim of the current study was to estimate the population prevalence of trachoma in non-indigenous populations in the Baixo Jaguaribe micro-region, in the state of Ceará, northeast region of Brazil, 2021-2022. METHODS: A population-based prevalence survey focusing on detecting cases of trachomatous inflammation-follicular (TF) in children aged 1-9 y and trachomatous trichiasis (TT) 'unknown to the health system' in people aged ≥15 y, was conducted in rural areas of the Baixo Jaguaribe micro-region in the state of Ceará. Indigenous populations will be further researched. RESULTS: There was no detection of cases of TF and TT. In 900 households, 2234 people were examined. In the Baixo Jaguaribe micro-region, females (54.6%; 1219/2234) and the mixed/Pardo-Brazilian ethnicity (68.1%; 1521/2234) predominated. The most commonly reported educational level was elementary and middle school (41.8%; 702/1679). In 56.2% (506/900) of households, there was a source of water within the household. The monthly income range of 50%-100% of the minimum wage predominated in the families of the Baixo Jaguaribe micro-region (43.1%; 388/900). CONCLUSIONS: Although no cases of TF and TT were detected in the Baixo Jaguaribe micro-region in the state of Ceará during the study period, considering the historical endemicity, we emphasise the need for monitoring and sustainability of surveillance actions in areas at risk for trachoma, common contexts for neglected populations.

Population Prevalence of Trachoma in Nine Rural Non-Indigenous Evaluation Units of Brazil.

PURPOSE: To assess the contemporary prevalence of trachoma in Brazil's non-indigenous population, surveys of those thought to be at greatest risk of disease were conducted. METHODS: Rural census tracts of non-indigenous population from nine mesoregions were selected to compose the survey evaluation units (EUs) by considering previously endemic municipalities at greatest risk of trachoma. In each of the nine EUs, we conducted a population-based prevalence survey. Every resident of selected households aged ≥1 year was examined for trachomatous inflammation - follicular (TF) and trachomatous trichiasis (TT). Additionally, data were collected on household-level access to water, sanitation, hygiene (WASH) and education. RESULTS: A total of 27,962 individuals were examined across nine EUs. The age-adjusted TF prevalence in 1-9-year-olds was <5% in each EU. The age- and gender-adjusted prevalence of TT unknown to the health system in ≥15-year-olds was <0.2% in eight EUs; in one EU, it was 0.22%. The median number of households surveyed per EU with access to an improved drinking water source within a 30-minute roundtrip of the house was 66%. School attendance was >99% of surveyed children. CONCLUSIONS: The prevalence of TF was well below the target for elimination as a public health problem in all EUs. Because EUs surveyed were selected to represent the highest-risk non-indigenous areas of the country, TF prevalence is unlikely to be ≥5% in non-indigenous populations elsewhere. In one EU, the prevalence of TT was above the target threshold for elimination. Further investigation and possibly improvement in TT surgical provision are required in that EU.

[Prevalence of respiratory symptoms in areas of the Federal District, Brazil]. / Prevalência de sintomáticos respiratórios em regiões do Distrito Federal, Brasil.

The identification of individuals with respiratory symptoms (RS) is important for the early detection of tuberculosis. The aim of this study was to estimate the prevalence of RS in three administrative regions of the Federal District, Brazil. For this, we used the 30 by 7 cluster sampling technique proposed by the World Health Organization. Individuals with RS were defined as those aged 15 years or older living in the administrative regions of Estrutural, Itapoã, or Varjão and reporting a cough lasting at least 3 weeks at the date of the interview. The prevalence of RS was 5.7% in Estrutural and Varjão (95% CI: 2.4-9.0) and 4.8% in Itapoã (95%CI: 1.6-7.9), with a design effect close to 1.0. In Estrutural and Itapoã, fewer years of schooling, and in Itapoã and Varjão, lower income, were associated with RS. Cigarette smoking was associated with the presence of RS in all regions. The prevalence of RS in the three administrative regions investigated is consistent with that of other areas with a similar socioeconomic profile.

Prevalence of trachoma in school children in the Marajó Archipelago, Brazilian Amazon, and the impact of the introduction of educational and preventive measures on the disease over eight years.

Trachoma is the leading infectious cause of blindness in the world and is associated with precarious living conditions in developing countries. The aim of the present study was to evaluate the prevalence of trachoma in three municipalities of the Marajó Archipelago, located in the state of Pará, Brazil. In 2008, 2,054 schoolchildren from the public primary school system of the urban area of the region and their communicants were clinically examined; in 2016, 1,502 schoolchildren were examined. The positive cases seen during the clinical evaluation were confirmed by direct immunofluorescence (DIF) laboratory tests. The presence of antibodies against the genus Chlamydia was evaluated by indirect immunofluorescence (IIF), and the serotypes were determined by microimmunofluorescence (MIF). In 2008, the prevalence of trachoma among schoolchildren was 3.4% (69 cases) and it was more frequent in children between six and nine years of age and in females; among the communicants, a prevalence of 16.5% was observed. In 2016, three cases of trachoma were diagnosed (prevalence of 0.2%), found only in the municipality of Soure. The results of the present study showed that in 2008, trachoma had a low prevalence (3.4%) among schoolchildren in the urban area of Marajó Archipelago; eight years after the first evaluation and the introduction of control and prevention measures (SAFE strategy), there was a drastic reduction in the number of cases (0.2%), demonstrating the need for constant monitoring and effective measures for the elimination of trachoma.

Epidemiology and control of trachoma in the state of Ceará, Northeast Brazil, 2007-2021

ABSTRACT Background: To analyze the epidemiology, surveillance, and control strategies for trachoma in the state of Ceará, northeast Brazil, from 2007 to 2021. Methods: This ecological study was based on secondary data from the Information System on Notifiable Diseases of the Secretary of Health of the state of Ceará. Data from school and home surveys for trachoma detection obtained during the study period were analyzed, the percentage of positivity was estimated, and sociodemographic and clinico-epidemiological factors were investigated. Results: The coverage of trachoma surveillance and control actions in Ceará municipalities increased from 12.5% in 2007 to 55.9% in 2019, but with an average restriction of 8.0% during the COVID-19 pandemic. The estimated trachoma positivity (mean overall positivity) was less than 5.0% (2.76%, 95% CI 1.2-5.2), with a higher proportion of cases in the 5-9-year age group (45.0%, 95% CI 44.6-45.4), in females (53.2%, 95% CI 52.8-53.6), and rural areas (52.6%, 95% CI 52.2-53.0). Positivity above 10.0% was observed in the Litoral Leste/Jaguaribe and Sertão Central regions, with a higher occurrence of the follicular inflammatory clinical form (98.1%, 95% CI 98.0-98.2). Conclusions: Trachoma remains in the state of Ceará and is likely underreported. Despite recent advances, the fragility of health surveillance activities compromises the recognition of the actual magnitude and distribution of trachoma in the state. Accurate information is fundamental for planning, monitoring, and evaluating surveillance and disease control.

Preliminary evidence that synanthropic flies contribute to the transmission of trachoma- causing Chlamydia trachomatis in Latin America.

Synanthropic flies have been shown to be important mechanical vectors of Chlamydia trachomatis, which causes trachoma. However entomological studies have not been forthcoming in Latin America. This study assesses the relationship between household dipteran fly densities and active childhood trachoma in a village on Marajó Island, Pará state, Brazil. For 78 households, members were examined for signs of trachoma, relative abundance of potential trachoma vectors (Diptera, Chloropidae and Diptera, Muscidae) was quantified by trap counts, and additional measures of household hygiene associated with C. trachomatis transmission were assessed. Active childhood trachoma prevalence was 24.1% (45/187), present in 46.2% of sampled households with evidence of case clustering. Childhood prevalence was positively associated with increased fly densities, whereas indirect measures of sanitary conditions (latrine ownership and perceived importance of flies) showed a protective effect. This study indicates that C. trachomatis can be transmitted by synanthropic flies in this region of Latin America.

Prevalence of Trachoma in Schoolchildren in Brazil.

PURPOSE: Trachoma was hyperendemic in Brazil until the 20th century. The prevalence has declined sharply in the past decades. The aim of this study was to estimate trachoma prevalence in schoolchildren in Brazilian municipalities with a Human Development Index (HDI) below the national mean. METHODS: A cluster random sampling survey on trachoma prevalence was carried out. Brazilian municipalities with HDI below the national mean, within each of the 27 states, were stratified into three strata according to population size. In each stratum, schools were systematically selected to comprise a sample of 2400 schoolchildren, totaling 7200 per state. In each selected school, children enrolled from 1st to 4th grade were examined for trachoma. The simplified trachoma grading system was used. At a meeting held in each school, the study was explained to parents, and verbal consent sought. RESULTS: A total of 185,862 children were enrolled in the selected schools. Of these, 171,973 (92.5%) participated in the study. The overall prevalence of trachomatous inflammation - follicular was 5.0% (95% confidence interval 4.7-5.3%), varying from 1.5% to 9.0% among the states. Prevalence was significantly associated with the sampling stratum (being higher in small municipalities), the zone in which the school was located (higher in rural schools), and with age (higher among younger children). CONCLUSION: Trachoma is still a public health problem in Brazil, although at a low level of endemicity. As the country advances towards the elimination of blinding trachoma, this survey provides a baseline for evaluation of ongoing and future elimination interventions.

Inquérito domiciliar de prevalência de tracoma em crianças do Distrito Federal, Brasil, julho/2010 / Survey of prevalence trachoma of children in Distrito Federal, Brazil, july/2010

Realizamos um estudo de corte transversal na Vila Estrutural (DF), utilizando amostragem por conglomerados. Os objetivos do estudo foram estimar a prevalência de tracoma em crianças de um a nove anos, descrever o perfil sociodemográfico dos casos e identificar possíveis fatores de risco associados à doença. A medida de associação foi razão de prevalência estimada pela odds ratio e o intervalo de confiança 95% (IC95%). Foram amostradas 766 crianças de 1 a 9 anos e encontrada prevalência de tracoma ativo de 12,5%. A alta prevalência observada reforça que a doença permanece como um problema de saúde pública, sendo necessária a adoção de medidas de controle, com vistas à eliminação da doença, enquanto causa de cegueira. Recomendamos capacitar profissionais da área para detecção e monitoramento de situação epidemiológica e adotar atividades de educação em saúde com enfoque em medidas de controle e prevenção.

We conducted a cross-sectional study in Vila Estrutural (DF) using cluster sampling. This study aimed to estimate prevalence of trachoma in children aged one to nine years, to describe the socio-demographic profile of cases, and to identify possible risk factors associated with the disease. The association measure was prevalence ratio estimated by odds ratio and 95% confidence interval (CI95%). We sampled 766 children aged 1 to 9 years and found a prevalence of active trachoma of 12.5%. The high prevalence reinforces that the disease remains a public health problem, being necessary to adopt control measures, in order to eliminate the disease as a cause of blindness. We recommend enabling professionals to detect and to monitor the epidemiological situation and adopt health education activities focusing on prevention and control measures.

Prevalência de sintomáticos respiratórios em regiões do Distrito Federal, Brasil / Prevalence of respiratory symptoms in areas of the Federal District, Brazil

A captação de sintomáticos respiratórios (SR) é importante para a detecção precoce de tuberculose. O objetivo deste estudo foi estimar a prevalência de SR em três regiões administrativas (RA) do Distrito Federal, Brasil. Para tanto, foi utilizada a técnica de amostragem por conglomerados (30 por 7) proposta pela Organização Mundial da Saúde. Foram definidos como SR os indivíduos com 15 anos ou mais residentes nas RAs Estrutural, Itapoã ou Varjão e que apresentassem tosse há pelo menos 3 semanas na data da entrevista. A prevalência de SR em Estrutural e Varjão foi de 5,7 por cento (IC95 por cento: 2,4 a 9,0), e em Itapoã, de 4,8 por cento (IC95 por cento: 1,6 a 7,9), com efeito de desenho próximo de 1,0. Em Estrutural e Itapoã, menos anos de estudo, e em Itapoã e Varjão, menor renda, estiveram associados com ser SR. O tabagismo esteve associado com a presença de sintomas respiratórios em todas as RAs. A prevalência de SR está de acordo com aquela encontrada em outras áreas com perfil socioeconômico semelhante ao das áreas estudadas.

The identification of individuals with respiratory symptoms (RS) is important for the early detection of tuberculosis. The aim of this study was to estimate the prevalence of RS in three administrative regions of the Federal District, Brazil. For this, we used the 30 by 7 cluster sampling technique proposed by the World Health Organization. Individuals with RS were defined as those aged 15 years or older living in the administrative regions of Estrutural, Itapoã, or Varjão and reporting a cough lasting at least 3 weeks at the date of the interview. The prevalence of RS was 5.7 percent in Estrutural and Varjão (95 percent CI: 2.4-9.0) and 4.8 percent in Itapoã (95 percentCI: 1.6-7.9), with a design effect close to 1.0. In Estrutural and Itapoã, fewer years of schooling, and in Itapoã and Varjão, lower income, were associated with RS. Cigarette smoking was associated with the presence of RS in all regions. The prevalence of RS in the three administrative regions investigated is consistent with that of other areas with a similar socioeconomic profile.

Preliminary evidence that synanthropic flies contribute to the transmission of trachoma- causing Chlamydia trachomatis in Latin America

Synanthropic flies have been shown to be important mechanical vectors of Chlamydia trachomatis, which causes trachoma. However entomological studies have not been forthcoming in Latin America. This study assesses the relationship between household dipteran fly densities and active childhood trachoma in a village on Marajó Island, Pará state, Brazil. For 78 households, members were examined for signs of trachoma, relative abundance of potential trachoma vectors (Diptera, Chloropidae and Diptera, Muscidae) was quantified by trap counts, and additional measures of household hygiene associated with C. trachomatis transmission were assessed. Active childhood trachoma prevalence was 24.1 percent (45/187), present in 46.2 percent of sampled households with evidence of case clustering. Childhood prevalence was positively associated with increased fly densities, whereas indirect measures of sanitary conditions (latrine ownership and perceived importance of flies) showed a protective effect. This study indicates that C. trachomatis can be transmitted by synanthropic flies in this region of Latin America.

Insetos sinantrópicos são importantes vetores mecânicos de Chlamydia trachomatis, causadora de tracoma, contudo, estudos entomológicos não são freqüentes na América Latina. Esse estudo determina a relação entre densidade de dípteros domésticos e tracoma ativo na infância em uma vila na Ilha do Marajó, Estado do Pará, Brasil. Moradores de 78 residências foram examinados para sinais de tracoma e a relativa abundância de potenciais vetores de tracoma (Diptera, Chloropidae e Diptera, Muscidae) foi quantificada junto com medidas adicionais de higiene doméstica associada com a transmissão de C. trachomatis. A prevalência de tracoma ativo na infância foi 24,1 por cento (45/187), presente em 46,3 por cento das residências amostradas com evidência de aglomeração de casos. A prevalência na infância foi positivamente associada com o aumento das densidades de insetos, enquanto medidas indiretas de condições sanitárias (possuir latrina e perceber a importância dos insetos) foram protetoras. Esse estudo indica que C. trachomatis pode ser transmitida por insetos sinantrópicos nessa região da América Latina.