Seroprevalence of SARS-CoV-2 antibodies in schoolchildren in the city of São Paulo, 2020.

OBJECTIVE: To estimate seroprevalence of SARS-CoV-2 antibodies in schoolchildren aged 4 to 14 years living in the city of São Paulo, according to clinical, demographic, epidemiological, and social variables, during the school closure period as a measure against covid-19 spread. METHODS: A serological survey was made in September 2020 with a random sample stratified by school system (municipal public, state public and private) type. A venous blood sample was collected using the Wondfo SARS-CoV-2 Antibody Test (lateral flow method) for detection of total SARS-CoV-2 virus antibodies. Semi-structured questionnaires were applied to collect clinical, demographic, social, and epidemiological data. RESULTS: Seroprevalence of SARS-CoV-2 antibodies in schoolchildren was of 16.6% (95%CI 15.4-17.8). The study found higher seroprevalence in the municipal (18.5%; 95%CI 16.6-20.6) and state (16.2%; 95%CI 14.4-18.2) public school systems compared to the private school system (11.7; 95%CI 10.0-13.7), among black and brown students (18.4%; 95%CI 16.8-20.2) and in the most vulnerable social stratum (18.5 %;95%CI 16.9-20.2). Lower seroprevalence was identified in schoolchildren who reported following the recommended protective measures against covid-19. CONCLUSION: Seroprevalence of SARS-CoV-2 antibodies is found mainly in the most socially vulnerable schoolchildren. This study can contribute to support public policies that reinforce the importance of suspending face-to-face classes and developing strategies aimed at protective measures and monitoring of the serological status of those who have not yet been included in the vaccination schedule.

Tolerance of microorganisms to residual herbicides found in eucalyptus plantations.

Competition with weeds is one of the main factors that limit the development of forest species. Some herbicides used to control these plants have a residual effect on the soil. Bioremediation is an alternative to decontaminate these areas. The aim of this study was to evaluate the tolerance of Aspergillus niger, Penicillium pinophilum and Trichoderma sp. and its degrading potential on residual effect herbicides. The tolerance of Bacillus subtilis, Pseudomonas sp. and Azospirillum brasilense to herbicides was also evaluated. The herbicides used in this study were indaziflam, sulfentrazone, sulfentrazone + diuron, clomazone and glyphosate + s-metolachlor. The analysis of the tolerance and degradation potential of fungi was carried out in Czapek Dox medium and the growth was evaluated by determining the biomass. Bacterial tolerance analysis was performed in Luria Bertani medium and growth monitored by optical density. The data were applied to the Gompertz model to evaluate the behavior of bacteria. Bacterial growth parameters were not influenced by the presence of herbicides. All fungi were tolerant to the herbicides tested and there was an increase in the growth of Trichoderma sp. Thus, the analysis of the degrading potential was performed only for Trichoderma sp. in the presence of herbicides that potentiated its growth. In this analysis, there was no effect of herbicides on fungal growth; the fungus was unable to use the carbon present in the herbicide to enhance its growth; and there was no significant effect of nitrogen in the presence of the herbicide. It is concluded, therefore, that the tested residual herbicides do not interfere with the development of the evaluated microorganisms.

Seroprevalence of SARS-CoV-2 antibodies in schoolchildren in the city of São Paulo, 2020 / Soroprevalência de anticorpos do vírus SARS-CoV-2 em escolares no município de São Paulo, 2020

ABSTRACT OBJECTIVE To estimate seroprevalence of SARS-CoV-2 antibodies in schoolchildren aged 4 to 14 years living in the city of São Paulo, according to clinical, demographic, epidemiological, and social variables, during the school closure period as a measure against covid-19 spread. METHODS A serological survey was made in September 2020 with a random sample stratified by school system (municipal public, state public and private) type. A venous blood sample was collected using the Wondfo SARS-CoV-2 Antibody Test (lateral flow method) for detection of total SARS-CoV-2 virus antibodies. Semi-structured questionnaires were applied to collect clinical, demographic, social, and epidemiological data. RESULTS Seroprevalence of SARS-CoV-2 antibodies in schoolchildren was of 16.6% (95%CI 15.4-17.8). The study found higher seroprevalence in the municipal (18.5%; 95%CI 16.6-20.6) and state (16.2%; 95%CI 14.4-18.2) public school systems compared to the private school system (11.7; 95%CI 10.0-13.7), among black and brown students (18.4%; 95%CI 16.8-20.2) and in the most vulnerable social stratum (18.5 %;95%CI 16.9-20.2). Lower seroprevalence was identified in schoolchildren who reported following the recommended protective measures against covid-19. CONCLUSION Seroprevalence of SARS-CoV-2 antibodies is found mainly in the most socially vulnerable schoolchildren. This study can contribute to support public policies that reinforce the importance of suspending face-to-face classes and developing strategies aimed at protective measures and monitoring of the serological status of those who have not yet been included in the vaccination schedule.

RESUMO OBJETIVO Estimar a soroprevalência de anticorpos do vírus SARS-CoV-2 em escolares de quatro a 14 anos de idade residentes no município de São Paulo, segundo variáveis clínicas, demográficas, epidemiológicas e sociais, durante o período de fechamento das escolas como medida de controle da covid-19. MÉTODOS Realizou-se um inquérito sorológico em setembro de 2020 com amostra aleatória estratificada por tipo de rede de ensino (pública municipal, pública estadual e privada). Foi coletada amostra de sangue venoso utilizando-se o teste de imunoensaio de fluxo lateral da fabricante Wondfo para detecção de anticorpos totais contra o vírus SARS-CoV-2. Aplicaram-se questionários semiestruturados para o levantamento de dados clínicos, demográficos, sociais e epidemiológicos. RESULTADOS A soroprevalência de anticorpos do vírus SARS-CoV-2 em escolares foi de 16,6% (IC95% 15,4-17,8). O estudo encontrou soroprevalências mais elevadas na rede pública municipal (18,5%; IC95% 16,6-20,6) e estadual (16,2%; IC95% 14,4-18,2) em relação à rede privada (11,7; IC95% 10,0-13,7) e entre escolares da raça/cor preta e parda (18,4%; IC95% 16,8-20,2) e no estrato social mais vulnerável (18,5%; IC95% 16,9-20,2). A pesquisa identificou menores soroprevalências nos escolares que relataram seguir as medidas recomendadas de proteção contra a covid-19. CONCLUSÃO A soroprevalência de anticorpos contra o vírus SARS-CoV-2 atinge principalmente os escolares socialmente mais vulneráveis. Este estudo pode contribuir para embasar políticas públicas que reforcem a importância da suspensão das aulas presenciais e da necessidade de estratégias de medidas de proteção e acompanhamento do status sorológico daqueles que ainda não foram contemplados no calendário vacinal.

Prevalence evolution of SARS-CoV-2 infection in the city of São Paulo, 2020-2021.

OBJECTIVE: To estimate the evolution of the prevalence of SARS-CoV-2 virus infection among residents aged 18 years or over in the municipality of São Paulo. METHODS: This is a population-based household survey conducted every 15 days, between June and September 2020, and January and February 2021. In total, the study comprised 11 phases. The presence of antibodies against SARS-CoV-2 was identified in venous blood using a lateral flow test, Wondfo Biotech. In the last phase, the researchers combined it with an immunoenzymatic test, Euroimmun. The participants also answered a semi-structured questionnaire on sociodemographic and economic factors, and on social distancing measures. Prevalence estimates and the 95% confidence interval were estimated according to regions, Human Development Index, sex, age group, ethnicity, education, income, and variables associated with risk or prevention of infection. To compare the frequencies among the categories of each variable, the chi-square test with Rao-Scott correction was used, considering a significance level of 5%. RESULTS: In total, 23,397 individuals were interviewed and had their samples collected. The estimated prevalence of antibodies against SARS-CoV-2 ranged from 9.7% (95%CI: 7.9-11.8%) to 25.0% (95%CI: 21.7-28.7). The prevalence of individuals with antibodies against the virus was higher among black and brown people, people with lower schooling and income, and among residents of regions with lower Human Development Index. The lowest prevalences were associated with recommended measures of disease protection. The proportion of asymptomatic infection was 45.1%. CONCLUSION: The estimated prevalence of the infection was lower than the cumulative incidence variation, except for the last phase of the study. The differences in prevalence estimates observed among subpopulations showed social inequality as a risk of infection. The lower prevalence observed among those who could follow prevention measures reinforce the need to maintain social distancing measures as a way to prevent SARS-CoV-2 infection.

Prevalence evolution of SARS-CoV-2 infection in the city of São Paulo, 2020-2021

ABSTRACT OBJECTIVE To estimate the evolution of the prevalence of SARS-CoV-2 virus infection among residents aged 18 years or over in the municipality of São Paulo. METHODS This is a population-based household survey conducted every 15 days, between June and September 2020, and January and February 2021. In total, the study comprised 11 phases. The presence of antibodies against SARS-CoV-2 was identified in venous blood using a lateral flow test, Wondfo Biotech. In the last phase, the researchers combined it with an immunoenzymatic test, Euroimmun. The participants also answered a semi-structured questionnaire on sociodemographic and economic factors, and on social distancing measures. Prevalence estimates and the 95% confidence interval were estimated according to regions, Human Development Index, sex, age group, ethnicity, education, income, and variables associated with risk or prevention of infection. To compare the frequencies among the categories of each variable, the chi-square test with Rao-Scott correction was used, considering a significance level of 5%. RESULTS In total, 23,397 individuals were interviewed and had their samples collected. The estimated prevalence of antibodies against SARS-CoV-2 ranged from 9.7% (95%CI: 7.9-11.8%) to 25.0% (95%CI: 21.7-28.7). The prevalence of individuals with antibodies against the virus was higher among black and brown people, people with lower schooling and income, and among residents of regions with lower Human Development Index. The lowest prevalences were associated with recommended measures of disease protection. The proportion of asymptomatic infection was 45.1%. CONCLUSION The estimated prevalence of the infection was lower than the cumulative incidence variation, except for the last phase of the study. The differences in prevalence estimates observed among subpopulations showed social inequality as a risk of infection. The lower prevalence observed among those who could follow prevention measures reinforce the need to maintain social distancing measures as a way to prevent SARS-CoV-2 infection.

Atrazine levels in the Jaboticabal water stream (São Paulo State, Brazil) and its toxicological effects on the pacu fish Piaractus mesopotamicus.

The aim of this study was to determine the environmental concentration of atrazine (ATZ) in five streams located in the north of São Paulo state (Brazil) and evaluate its toxicological impact on young specimens of the pacu fish Piaractus mesopotamicus. Samples of water were collected on three occasions between 2010 and 2011, corresponding to periods signifying the beginning, middle, and end of rain season. ATZ levels were estimated by a high-performance liquid chromatography coupled with a mass spectrometry (HPLC-MS/MS) triple quadrupole. Later, the quotient of environmental risk (QR) was determined based on the medium lethal concentration (LC50 48 h), non-observable effect concentration (NOEC), and the estimated environmental concentration (EEC) of ATZ detected in the environment. Histological changes in gills and liver were also studied, along with the brain activity of the enzyme acetylcholinesterase (AChE). The highest concentration of ATZ measured was 10.4 µg L(-1). The ATZ LC50 (48 h) for young P. mesopotamicus was 24.46 mg L(-1) and the QR was classified as "safe". Although the QR indicated that ATZ could be safe for the tested species, it caused many histological alterations in the liver and gills of the exposed specimens, and an increase in the AChE levels.