Increasing rate of anti-SARS-CoV-2 antibodies between the first and second waves of COVID-19 in Sao Paulo, Brazil: A cross-sectional blood donors-based study

ABSTRACT Background: SARS-CoV-2 infections rapidly spread along with Brazilian territory with heterogeneous transmission and mortality rates, mostly depending on region and period. Investigation of SARS-CoV-2 antibodies is an important tool to understand virus circulation. Given that blood donors are a representative casuistic of a healthy population, the authors evaluated the seroprevalence of IgG and IgM COVID-19 antibodies in 2,806 blood donors from a blood bank located in São Paulo, Brazil. Methods: Aiming to evaluate viral behavior over time, the authors selected samples from blood donors who donated in June and October 2020, and February 2021. To determine whether socio-demographic features affected the seroprevalence, the authors analyzed samples from three different regions from São Paulo (capital, metropolitan and countryside regions) and evaluated predictors as gender, age, educational level, race, and use of public transportation. Results: As expected, the authors observed that seroprevalence increased over time. Seroprevalence was greater in São Paulo city compared to metropolitan and countryside regions, being smallest in the countryside. Characteristics associated with a lower percentage of antibodies were age above 50 years, higher educational level, self-declared Caucasian, and use of individual transportation. Conclusion: In conclusion, blood donors' samples proved to accurately reflect virus circulation in the healthy population.

In vitro antiviral activity of propolis and Baccharis sp. extracts on animal herpesviruses / Atividade antiviral in vitro de extratos de própolis e de Baccharis sp. sobre herpes vírus animal

This study evaluated the in vitro antiviral activity of propolis and Baccharis sp. extracts on three animal herpesviruses (bovine, equine and swine). The propolis samples were produced by two species of bees. There was red and green propolis, which came from africanized Apis melifera, and a third type obtained from a native bee species, Tetragonisca angustula (jatai). The Baccharis extracts were obtained from four different species: B. oblongifolia, B. burchellii, B. dracunculifolia and B. uncinella. The maximum non-toxic concentration of the extracts was determined when no visible morphological changes were observed on the cells. These non-toxic concentrations were used in the antiviral tests. Antiviral activity was evaluated using a reduction assay of the cytopathic effect, which calculated the difference between treated and control virus titer by statistical analysis. Red propolis was active against the three herpesviruses and green propolis showed inhibition against the equine and swine herpesviruses. Conversely, jataí propolis showed no antiviral activity. Most extracts coming from male and female individuals of all of the Baccharis species showed antiviral activity against bovine and swine herpesviruses. Only the extract of the female specimen of B. oblongifolia was an inhibitor against equine herpesvirus.(AU)

O trabalho avaliou a atividade antiviral in vitro de própolis e espécies de Baccharis sobre três herpes vírus animais (bovino, equino e suíno). As própolis foram produzidas por duas espécies de abelhas. Pela Apis melifera (abelha africanizada) foram obtidas duas própolis, vermelha e verde, e uma terceira foi obtida pela abelha nativa Tetragonisca angustula (abelha jataí). Os extratos de Baccharis foram obtidos de 4 espécies diferentes: B. ­oblongifolia, B. burchellii, B. dracunculifolia e B. uncinella. A concentração máxima não tóxica dos extratos foi determinada pela ausência de alterações morfológicas nas células, e essas concentrações então utilizadas nos testes antivirais. A atividade antiviral foi avaliada pela redução do efeito citopático e calculada a partir da diferença entre o título viral do tratado pelo controle e feita a análise estatística. A própolis vermelha foi ativa contra os três herpes vírus, e a própolis verde apresentou inibição contra os herpes vírus equino e suíno, enquanto a própolis da abelha jataí não apresentou atividade antiviral. A maioria dos extratos dos indivíduos masculinos e femininos de todas as espécies de Baccharis apresentou atividade antiviral contra os herpes vírus bovino e suíno. Apenas o extrato do indivíduo feminino de B. oblongifolia foi inibidor contra o herpes vírus equino.(AU)