Background: A population study is an important tool that can be used to understand the actual epidemiological scenario of the Covid-19 in different territories, identify its magnitude, understand its transmission dynamics, and its demographic, geographical, and social distribution. Objective: The aim of this study was to determine the prevalence and dynamics of SARS-CoV-2 infection in the population of two Brazilian cities during the pandemic first wave and subsequent socioeconomic and health effects. Materials & methods: This paper described the methodological procedures adopted and the prevalence of the SARS-CoV-2 infection in the population. A household survey was conducted between October and December 2020, in two historic cities of Brazil's mining region. Anti-SARS-CoV-2 antibody was detected using the Wondfo® rapid test. The face-to-face interview consisted of administration of a questionnaire containing registration data, sociodemographic and economic variables, living habits, general health condition, mental health, sleep habits, and eating and nutrition. Results: We evaluated 1,762 residents, of which 764 (43.4%) were in Mariana and 998 (56.6%) in Ouro Preto. For both cities, 51.9% of the interviewees were female, with a predominance of the age range 35 to 59 years old (47.2%). The prevalence of the SARS-CoV-2 infection was 5.5% in all cities, 6.2% in Ouro Preto, and 4.7% in Mariana. The prevalence was similar between cities (P>0.05). Conclusion: The study was effective in verifying the seroprevalence of infection by the virus and its findings will enable further analyses of the health conditions of the population related to social isolation and the risk of infection with SARS-CoV-2.

Resumo Objetivo: analisar os fatores sociodemográficos relacionados ao não uso do preservativo nas relações sexuais e a prevalência de infecções sexualmente transmissíveis (IST) em comunidades rurais de Ouro Preto, Minas Gerais, Brasil, entre 2014 e 2016. Métodos: foram coletados dados de entrevista individual e realizados testes rápidos; as associações foram testadas pelo modelo de regressão de Poisson, com intervalo de confiança de 95% (IC95%). Resultados: foram detectados 3,8 casos/10 mil habitantes de hepatite B e sífilis, e 1,3/10 mil hab. de hepatite C; não foram detectados casos de HIV; na análise multivariada, foram encontradas maiores prevalências de não uso de preservativos entre indivíduos casados/em união estável/viúvos (RP=1,20 - IC95% 1,06;1,36). Conclusão: o grupo com maior prevalência de não uso de preservativo é o de pessoas com relacionamento fixo; novos casos de sífilis e de hepatites virais foram detectados pelo teste rápido, aplicado no inquérito.

Abstract Objective: to investigate socio-demographic factors associated with non-use of condoms, and to describe the prevalence of sexually transmitted infections (STI) in rural communities of Ouro Preto, Minas Gerais, Brazil, 2014 to 2016. Methods: data were gathered from individual interviews and rapid tests were performed; associations were tested using Poisson regression, with a 95% confidence interval (95%CI). Results: we detected 3.8 cases/10,000 inhabitants for hepatitis B and syphilis, and 1.3 cases/10,000 inhabitants for hepatitis C; no HIV cases were detected; in the multivariate analysis we found higher prevalence rates of condom non-use among the group of individuals who were married, had common law partners or were widowed (PR=1.20 - 95%CI 1.06;1.36). Conclusion: individuals in a stable relationship formed the group with the highest prevalence rate of condom non-use; new syphilis and viral hepatitis cases were detected using rapid tests during the survey.

Resumen Objetivo: investigar el perfil sociodemográfico asociado al no uso del preservativo en las relaciones sexuales y describir la prevalencia de infecciones de transmisión sexual (ITS) en comunidades rurales de Ouro Preto, Minas Gerais, Brasil, entre 2014 y 2016. Métodos: se recolectaron datos en entrevista individual y se realizaron pruebas rápidas; las asociaciones fueron analizadas por la regresión de Poisson, con intervalo de confianza de 95% (IC95%). Resultados: se detectaron 3,8 casos/10 mil habitantes de hepatitis B y sífilis, y 1,3/10 mil habitantes de hepatitis C; no se detectaron casos de VIH; el análisis multivariado mostró mayor prevalencia de no uso del preservativo para personas casadas /en unión estable/viudos (RP=1,20 - IC95% 1,06;1,36). Conclusión: se detectaron nuevos casos de sífilis y hepatitis virales por las pruebas rápidas en esta investigación; el grupo de mayor riesgo de no usar preservativo fue de personas casadas/con relación fija.

Resumo Objetivo: analisar os fatores sociodemográficos relacionados ao não uso do preservativo nas relações sexuais e a prevalência de infecções sexualmente transmissíveis (IST) em comunidades rurais de Ouro Preto, Minas Gerais, Brasil, entre 2014 e 2016. Métodos: foram coletados dados de entrevista individual e realizados testes rápidos; as associações foram testadas pelo modelo de regressão de Poisson, com intervalo de confiança de 95% (IC95%). Resultados: foram detectados 3,8 casos/10 mil habitantes de hepatite B e sífilis, e 1,3/10 mil hab. de hepatite C; não foram detectados casos de HIV; na análise multivariada, foram encontradas maiores prevalências de não uso de preservativos entre indivíduos casados/em união estável/viúvos (RP=1,20 - IC95% 1,06;1,36). Conclusão: o grupo com maior prevalência de não uso de preservativo é o de pessoas com relacionamento fixo; novos casos de sífilis e de hepatites virais foram detectados pelo teste rápido, aplicado no inquérito.

Abstract Objective: to investigate socio-demographic factors associated with non-use of condoms, and to describe the prevalence of sexually transmitted infections (STI) in rural communities of Ouro Preto, Minas Gerais, Brazil, 2014 to 2016. Methods: data were gathered from individual interviews and rapid tests were performed; associations were tested using Poisson regression, with a 95% confidence interval (95%CI). Results: we detected 3.8 cases/10,000 inhabitants for hepatitis B and syphilis, and 1.3 cases/10,000 inhabitants for hepatitis C; no HIV cases were detected; in the multivariate analysis we found higher prevalence rates of condom non-use among the group of individuals who were married, had common law partners or were widowed (PR=1.20 - 95%CI 1.06;1.36). Conclusion: individuals in a stable relationship formed the group with the highest prevalence rate of condom non-use; new syphilis and viral hepatitis cases were detected using rapid tests during the survey.

Resumen Objetivo: investigar el perfil sociodemográfico asociado al no uso del preservativo en las relaciones sexuales y describir la prevalencia de infecciones de transmisión sexual (ITS) en comunidades rurales de Ouro Preto, Minas Gerais, Brasil, entre 2014 y 2016. Métodos: se recolectaron datos en entrevista individual y se realizaron pruebas rápidas; las asociaciones fueron analizadas por la regresión de Poisson, con intervalo de confianza de 95% (IC95%). Resultados: se detectaron 3,8 casos/10 mil habitantes de hepatitis B y sífilis, y 1,3/10 mil habitantes de hepatitis C; no se detectaron casos de VIH; el análisis multivariado mostró mayor prevalencia de no uso del preservativo para personas casadas /en unión estable/viudos (RP=1,20 - IC95% 1,06;1,36). Conclusión: se detectaron nuevos casos de sífilis y hepatitis virales por las pruebas rápidas en esta investigación; el grupo de mayor riesgo de no usar preservativo fue de personas casadas/con relación fija.

ABSTRACT Intestinal parasitic infections are a common health problem among Amerindian populations and schistosomiasis represents one of the most prevalent diseases in Maxakali people. The Kato-Katz is the diagnostic method recommended by WHO for epidemiological studies; however, one of the technique’s limitations is the failure to detect parasites in individuals with low parasite load. The aim of this study was to establish the prevalence of Schistosoma mansoni in indigenous Maxakali villages, evaluating the TF-Test® performance for diagnosis compared to the Kato-Katz technique. Stool samples from 545 individuals were processed by the TF-Test® (1 sample) and Kato-Katz (1 slide). The positivity rate for S. mansoni by Kato-Katz was 45.7%. The rate by the TF-Test® was 33.2%, and 51.9% by the combined parasitological techniques. The amplitude of parasite load was 24 to 4,056 eggs per gram of feces (epg), with a geometric mean of 139 epg. The co-positivity, co-negativity, and accuracy values by TF-Test® in relation to Kato-Katz were 59.0%, 88.5%, and 75.0%, respectively. The agreement between these techniques was moderate (k=0.486) as determined by the kappa index. Thus, the results of this study demonstrated that the performance of Kato-Katz was superior (p <0.05) to that of TF-Test® in the detection of S. mansoni. The combination of TF-Test® and Kato-Katz resulted in an increased positivity rate of S. mansoni, demonstrating the high risk of infection to which indigenous populations are exposed and the importance of the implementation of control strategies in Maxakali villages.