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BackgroundSince the emergence of the COVID-19, health officials have struggled to devise strategies to counteract the speed of the pandemic’s spread across the globe. It became imperative to implement accurate diagnostic tests for the detection of SARS-CoV-2 RNA on respiratory samples. In many places, however, besides the limited availability of test reagents, laboratory personnel face the challenge of adapting their working routines to manipulate highly infective clinical samples. Here, we proposed the use of a virus-inactivating solution as part of a sample collection kit to decrease the infectious potential of the collected material without affecting the integrity of RNA samples used in diagnostic tests based on RT-qPCR.MethodsNasopharyngeal and oropharyngeal swab samples were collected from SARS-CoV-2-infected patients and from laboratory personnel using a commercially available viral transport solution (VTM) and the denaturing solution (DS) described here. RNA extracted from all samples was tested by RT-qPCR using probes for viral and human genes. Exposure of laboratory personnel to infective viruses was also accessed using ELISA tests.FindingsThe use of the DS did not interfere with the detection of viral genome or the endogenous human mRNA, since similar results were obtained from samples collected with VTM or DS. In addition, all tests of laboratory personnel for the presence of viral RNA and IgG antibodies against SARS-CoV-2 were negative.InterpretationThe methodology described here provides a strategy that allow high diagnostic accuracy as well as safe manipulation of clinical samples by those involved with diagnostic procedures.FundingCAPES, FAPEMIG, CNPq, MCTIC, FIOCRUZ and the UK Global Challenges Research Fund (GCRF).

There is a massive demand to identify alternative methods to detect new cases of COVID-19 as well as to investigate the epidemiology of the disease. In many countries, importation of commercial kits poses a significant impact on their testing capacity and increases the costs for the public health system. We have developed an ELISA to detect IgG antibodies against SARS-CoV-2 using a recombinant viral nucleocapsid (rN) protein expressed in E. coli. Using a total of 894 clinical samples we showed that the rN-ELISA was able to detect IgG antibodies against SARS-CoV-2 with high sensitivity (97.5%) and specificity (96.3%) when compared to a commercial antibody test. After three external validation studies, we showed that the test accuracy was higher than 90%. The rN-ELISA IgG kit constitutes a convenient and specific method for the large-scale determination of SARS-Cov-2 antibodies in human sera with high reliability.

Chikungunya virus (CHIKV) is a mosquito-borne pathogen that causes a disease characterized by the acute onset of fever accompanied by arthralgia and intense joint pain. Clinical similarities and cocirculation of this and other arboviruses in many tropical countries highlight the necessity for efficient and accessible diagnostic tools. CHIKV envelope proteins are highly conserved among alphaviruses and, particularly, the envelope 2 glycoprotein (CHIKV-E2) appears to be immunodominant and has a considerable serodiagnosis potential. Here, we investigate how glycosylation of CHIKV-E2 affects antigen/antibody interaction and how this affects the performance of CHIKV-E2-based Indirect ELISA tests. We compare two CHIKV-E2 recombinant antigens produced in different expression systems: prokaryotic-versus eukaryotic-made recombinant proteins. CHIKV-E2 antigens are expressed either in E. coli BL21(DE3)&mdash, a prokaryotic system unable to produce post-translational modifications&mdash, or in HEK-293T mammalian cells&mdash, a eukaryotic system able to add post-translational modifications, including glycosylation sites. Both prokaryotic and eukaryotic recombinant CHIKV-E2 react strongly to anti-CHIKV IgG antibodies, showing accuracy levels that are higher than 90%. However, the glycan-added viral antigen presents better sensitivity and specificity (85 and 98%) than the non-glycosylated antigen (81 and 71%, respectively) in anti-CHIKV IgM ELISA assays.

We describe here the development of an in-house enzyme linked immunosorbent assay (ELISA) for the diagnostic of Chikungunya virus (CHIKV) infections using a recombinant protein from CHIKV. The recombinant protein gene was designed based on 154 sequences and we used computational methods to predict its structure and antigenic potential. To confirm predictions, the gene coding for the recombinant CHIKV protein (rCHIKVp) was synthetized and expressed in prokaryotic system. Subsequently, the protein was purified by affinity chromatography and used as antigen in an indirect ELISA. We present data regarding the optimization of the recombinant antigen production and preparation of the ELISA to detect IgG against CHIKV in human sera. Keywords: Chikungunya virus, Diagnostics, ELISA, E2 Envelope protein, Recombinant protein

Chikungunya (CHIKV), an arbovirus that belongs to the Alphavirus genus of the Togaviridae family, causes a disease characterized by acute onset of fever accompanied by arthralgia. CHIKV also has been associated with cases of meningoencephalitis (primarily in neonates), Guillain–Barre syndrome and hemorrhagic disease. The clinical similarities, cross-reactivity and cocirculation of arboviruses in Brazil have complicated their differentiation, highlighting the need for new diagnostic tools. A serologic test can be useful for acute detections as well as for surveillance and epidemiological studies. Point of care tests currently available to detect CHIKV infections have been associated with low accuracy. The aim of this work was to design a synthetic gene and generate a recombinant protein to be used as antigens in diagnostic assays. Computational methods were used to predict its structure and antigenic potential. To confirm predictions, the gene coding for the recombinant CHIKV protein (rCHIKV) was synthetized and the protein was purified by affinity chromatography. Antigenicity of the protein was initially confirmed by western-blot using sera from CHIKV infected mice. Additionally, the seroreactivity of r-CHIKV protein was evaluated using a panel of sera samples from human patients, CHIKV seropositive or not, by indirect IgG ELISA. The r-CHIKV protein showed sensitivity of 95 % and specificity of 96 %. No cross-reactivity was found against sera of Zika and Dengue positive patients. These results indicate that this proteins maybe useful antigen to detect CHIKV infections in ELISA assays. Our next step includes the development of a rapid test kit.

Background Chikungunya virus (CHIKV) causes a disease characterized by acute onset of fever accompanied by arthralgia. Clinical similarities and co-circulation of other arboviruses such as Dengue virus (DENV) and Zika virus (ZIKV), have complicated their differentiation, making their diagnoses a challenge for the health authorities. Misdiagnosis is a serious issue to the management of patients and development of public health measures. Objectives We carried out further screening of CHIKV, DENV and ZIKV cases in Minas Gerais, Brazil, after diagnostics were already issued by a state laboratory and according to the Brazilian Ministry of Health (BMH) policy. Our aim was to look for possible co-infections or previous arboviruses’ exposure. Study design Sera from 193 patients with symptoms of arboviral infections were tested for DEV, ZKV and/or CHIKV by the State laboratory, according to clinical suspicion and following standard BMH guidelines. After an official diagnosis was issued for each patient, we retested samples applying a broader panel of ELISA-based serological tests. Results We identified 13 patients with concurrent or consecutive infections (IgM positive for more than one arbovirus), including 11 individuals that were positive for CHIKV and other previously confirmed arbovirus infection. Discussion Guidelines established in many arbovirus-endemic countries prioritizes the diagnosis of Zika and Dengue and no further analyzes are done when samples are positive for those viruses. As a result, possible cases of co-infections with chikungunya are neglected, which affects the epidemiological assessments of virus circulation, patient management, and the development of public health policies.

A formação continuada de professores do Ensino Médio, no que tange as ciências da natureza, tem o desafio de incorporar, no conteúdo programático, as pesquisas e tecnologias inovadoras resultantes das novas descobertas no campo da Bioquímica e da Biologia Molecular. O presente trabalho relata a experiência de um projeto de extensão que objetivou a capacitação de professores de Biologia e de Química para o uso de novos métodos de ensino-aprendizagem visando despertar maior interesse dos estudantes pela Ciência. Resultado de parceria entre professores e estudantes universitários com educadores de escolas públicas, o presente projeto possibilitou a capacitação de 34 professores oriundos de 17 diferentes escolas para a utilização de um método de ensino-aprendizagem baseado no emprego de modelos didáticos lúdicos e de problematização da realidade quanto ao consumo de tecnologias e produtos biotecnológicos. Continued education of high school teachers regarding natural sciences has been challenging in terms of incorporating researches and innovative technologies from discoveries in the field of biochemistry and molecular biology in the curriculum. This paper describes the experience of an extension project aimed at training biology and chemistry teachers for the use of new teaching and learning methods to arouse a greater interest of students for science. Resulting from a partnership between professors and undergraduate students with public school teachers, this project enabled the training of 34 teachers from 17 different schools. The teaching-learning method establishes on the use of didactic models as well as the problem-based knowledge of reality regarding the consumption of technology and biotechnology products. La continua formación de los profesores de educación secundaria con respecto a las ciencias naturales, tiene el desafío de ir incorporando en el contenido programático los resultados de las investigaciones y las tecnologías innovadoras descubiertos en el campo de la bioquímica y la biología molecular. El presente trabajo relata la experiencia de un proyecto de extensión cuyo objetivo es la capacitación de profesores de biología y de química para el uso de nuevos métodos de enseñanza y aprendizaje, buscando despertar un mayor interés de los estudiantes por la ciencia. Como resultado de la asociación entre profesores y estudiantes con docentes de colegios públicos, el presente proyecto posibilitó la capacitación de 34 profesores de 17 diferentes colegios en el uso del método de enseñanza-aprendizaje basado en el empleo de modelos ludo-didácticos y de problematización de la realidad en cuanto al consumo de tecnologías y productos biotecnológicos.