Advances in molecular biology research on human parvovirus B19 / 生物工程学报

Human parvovirus B19 (B19 virus) is one of the two parvoviruses that cause human diseases. As an important pathogen to humans, it causes infectious erythema in children, acute aplastic anemia, fetal edema and death. In this review, we focus on the recent advances in the molecular virology of B19V, such as viral genotypes, viral receptor, genomic features and viral replication, viral transcription and post-transcription regulation, viral nonstructural and structural protein features and functions, viral diagnosis and antiviral agents, to provide reference for further study of B19 pathogenesis mechanisms, treatment and diagnostic strategies.

False-negative result in molecular diagnosis of SARS-CoV-2 in samples with amplification inhibitors / Resultado falso negativo no diagnóstico molecular de SARS-CoV-2 em amostras com inibidores de amplificação

ABSTRACT Introduction: Although reverse transcription-polymerase chain reaction (rRT-PCR) is the gold standard method for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some factors, such as the presence of amplification inhibitors, lead to false-negative results. Objective: Here we describe the differences between rRT-PCR results for SARS-CoV-2 infection in normal and diluted samples, simulating the need for dilution due to the presence of amplification inhibitors. Material and method: Viral ribonucleic acid (RNA) from samples of nasopharyngeal swabs from 20 patients previously detected as "Negative" and 21 patients detected as "Positive" for SARS-CoV-2 was performed with the EasyExtract DNA-RNA kit (Interprise®). The rRT-PCR was performed with the OneStep/COVID-19 kit (IBMP), with normal and diluted (80 µl of H2O RNAse free) samples, totaling 82 tests. Results: The results indicate that there is an average variation (a < 0.05) delaying the Cq between the results of amplification of the internal control (IC), N gene (NG), and ORF1ab (OF), 1.811 Cq, 3.840 Cq, and 3.842 Cq, respectively. Discussion: The extraction kit does not completely purify the inhibitor compounds; therefore, no amplified product result may occur. In this study, we obtained a 19.04% false-negative diagnosis after sample dilution; this process reduces the efficiency of rRT-PCR to 29.8% in detecting SARS-CoV-2. Conclusion: Knowing the rRT-PCR standards of diluted samples can assist in the identification of false-negative cases and, consequently, avoid incorrect diagnosis.

RESUMEN Introducción: Aunque la reacción en cadena de la polimerasa con transcriptasa reversa en tiempo real (rRT-PCR) sea el método de referencia para detección del coronavirus tipo 2 del síndrome respiratorio agudo grave (Sars-CoV-2), algunos factores como la presencia de inhibidores de amplificación conducen a resultados falsos negativos. Objetivo: Describimos las diferencias entre los resultados de rRT-PCR para infección por Sars-CoV-2 en muestras normales y diluidas, simulando la necesidad de dilución debido a la presencia de inhibidores de amplificación. Material y método: La extracción de ácido ribonucleico (ARN) viral de muestras de hisopos nasofaríngeos de 20 pacientes previamente detectados como "negativos" y 21 pacientes detectados como "positivos" para Sars-CoV-2 se realizó con el kit Easy Extract DNA-RNA (Interprise®). La rRT-PCR se realizó con el kit OneStep/Covid-19 (IBMP), con muestras normales y diluidas (80 µl de H2O libre de ARNasa), totalizando 82 pruebas. Resultados: Los resultados indican que hay una variación media (a < 0,05) retrasando el ciclo de cuantificación (Cq) entre los resultados de amplificación del control interno (CI), gen N (GN) y ORF1ab (OF) de 1,811 Cq, 3,840 Cq y 3,842 Cq. Discusión: El kit de extracción no purifica completamente los compuestos inhibidores; por lo tanto, puede ocurrir no amplificación. Obtuvimos un diagnóstico falso negativo de 19,04% después de la dilución de la muestra; ese proceso reduce la eficiencia de la rRT-PCR hacia 29,8% en la detección de Sars-CoV-2. Conclusión: Conocer los patrones de la rRT-PCR de muestras diluidas puede ayudar en la identificación de casos falsos negativos y, por consiguiente, evitar un diagnóstico equivocado.

RESUMO Introdução: Embora a reação em cadeia da polimerase de transcrição reversa (rRT-PCR) seja o método padrão-ouro para detecção de coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2), alguns fatores como a presença de inibidores de amplificação levam a resultados falso negativos. Objetivo: Descrevemos as diferenças entre os resultados de rRT-PCR para infecção por SARS-CoV-2 em amostras normais e diluídas, simulando a necessidade de diluição devido à presença de inibidores de amplificação. Material e método: A extração de ácido ribonucleico (RNA) viral de amostras de suabes nasofaríngeos de 20 pacientes previamente detectados como "negativos" e 21 pacientes detectados como "positivos" para SARS-CoV-2 foi realizada com kit o EasyExtract DNA-RNA (Interprise®). A rRT-PCR foi realizada com o kit OneStep/COVID-19 (IBMP), com amostras normais e diluídas (80 µl de H2O RNAse-free), totalizando 82 testes. Resultados: Os resultados indicam que existe uma variação média (a < 0,05) atrasando o Cq entre os resultados de amplificação do controle interno (CI), gene N (GN) e ORF1ab (OF) de 1,811 Cq, 3,840 Cq e 3,842 Cq, respectivamente. Discussão: O kit de extração não purifica completamente os compostos inibidores, portanto, pode ocorrer não amplificação. Obtivemos um diagnóstico falso negativo de 19,04% após a diluição da amostra; esse processo reduz a eficiência da rRT-PCR para 29,8% na detecção de SARS-CoV-2. Conclusão: Conhecer os padrões da rRT-PCR de amostras diluídas pode auxiliar na identificação de casos falso negativos e, consequentemente, evitar um diagnóstico incorreto.

Factores asociados al desarrollo de la bronquiolitis / Associated factors with the development of the bronchiolitis

RESUMEN Fundamento: la bronquiolitis aguda es una enfermedad de etiología viral caracterizada por obstrucción de la pequeña vía aérea que afecta a los niños menores de 24 meses. Objetivo: determinar los factores asociados al desarrollo de la bronquiolitis aguda. Métodos: se realizó un estudio de casos y controles en el municipio de Guáimaro, provincia Camagüey, entre junio de 2016 a diciembre de 2017. Los casos fueron 37 niños menores de dos años con diagnóstico clínico de bronquiolitis e igual cantidad de niños sin este diagnóstico conformaron los controles. La información se obtuvo mediante un cuestionario a los padres, donde se obtuvo información sobre: la edad del niño, el sexo, la severidad, edad gestacional al nacer, vía de nacimiento, peso al nacer, lactancia materna exclusiva, historia de atopia familiar, concurrir a circulo infantil, hermanos en edad escolar, madre fumadora en el embarazo y exposición al humo del tabaco en el domicilio. Resultados: hubo predominio de los menores de seis meses de sexo masculino y clasificado de leves. Las condiciones que mostraron asociación estadística con la aparición de la bronquiolitis fueron: madre fumadora en el embarazo, ausencia de lactancia materna exclusiva, la historia familiar de atopia y la exposición al humo del tabaco en el domicilio. Conclusiones: fueron los factores de riesgo para el desarrollo de la bronquiolitis: el fumar en el embarazo, ausencia de lactancia materna exclusiva, la historia familiar de atopia y la exposición al humo del tabaco en el domicilio.

ABSTRACT Background: the acute bronchiolitis is a disease caused by viruses that produced obstruction of the airways in children less than two years old. Objective: to determine the factors associated with the development of acute bronchiolitis. Methods: a case-control study was made in Guáimaro, Camagüey province, Cuba from June 2015 to January 2017. The cases were 37 children under two years old with diagnostic of bronchiolitis and the same number of children without diagnostic were the controls. The information was obtained through a questionnaire applied to parents of children. The variables analyzed were age, gender, severity, weight at birth, gestational age at birth, childbirth, breastfeeding, family history of atopic disease, siblings in scholar age, nursery assistance, smoker mother during pregnancy and exposition to tobacco smoke in the home. Results: there was predominance of the minors of six months, of masculine sex and classified of light. There was significant relationships between bronchiolitis and the smoker mother during pregnancy, absence of exclusive breastfeeding, family history of atopic disease and exposition to tobacco smoke in the home. Conclusions: were factors for the development of bronchiolitis: mother smoked during pregnancy, absence of exclusive breastfeeding, family history of atopic disease and exposition to tobacco smoke in the home.

Comparison of enterovirus detection in cerebrospinal fluid with Bacterial Meningitis Score in children / Comparação da pesquisa de enterovírus no liquor com Escore de Meningite Bacteriana em crianças

ABSTRACT Objective To measure the role of enterovirus detection in cerebrospinal fluid compared with the Bacterial Meningitis Score in children with meningitis. Methods A retrospective cohort based on analysis of medical records of pediatric patients diagnosed as meningitis, seen at a private and tertiary hospital in São Paulo, Brazil, between 2011 and 2014. Excluded were patients with critical illness, purpura, ventricular shunt or recent neurosurgery, immunosuppression, concomitant bacterial infection requiring parenteral antibiotic therapy, and those who received antibiotics 72 hours before lumbar puncture. Results The study included 503 patients. Sixty-four patients were excluded and 94 were not submitted to all tests for analysis. Of the remaining 345 patients, 7 were in the Bacterial Meningitis Group and 338 in the Aseptic Meningitis Group. There was no statistical difference between the groups. In the Bacterial Meningitis Score analysis, of the 338 patients with possible aseptic meningitis (negative cultures), 121 of them had one or more points in the Bacterial Meningitis Score, with sensitivity of 100%, specificity of 64.2%, and negative predictive value of 100%. Of the 121 patients with positive Bacterial Meningitis Score, 71% (86 patients) had a positive enterovirus detection in cerebrospinal fluid. Conclusion Enterovirus detection in cerebrospinal fluid was effective to differentiate bacterial from viral meningitis. When the test was analyzed together with the Bacterial Meningitis Score, specificity was higher when compared to Bacterial Meningitis Score alone.

RESUMO Objetivo Avaliar o papel da pesquisa de enterovírus no líquido cefalorraquidiano em comparação com o Escore de Meningite Bacteriana em crianças com meningite. Métodos Coorte retrospectiva, realizada pela análise de prontuários, incluindo pacientes pediátricos, com diagnóstico de meningite e atendidos em um hospital privado e terciário, localizado em São Paulo, entre 2011 e 2014. Foram excluídos os pacientes com doença crítica, púrpura, derivação ventricular ou neurocirurgia recente, imunossupressão, outra infecção bacteriana concomitante que necessitasse de antibioticoterapia parenteral e aqueles que receberam antibiótico 72 horas antes da punção lombar. Resultados Foram incluídos no estudo 503 pacientes. Destes, 64 foram excluídos e 94 não realizaram todos os exames para análise. Dos 345 pacientes restantes, 7 ficaram no Grupo de Meningite Bacteriana e 338 no Grupo de Meningite Asséptica. Não houve diferença estatística entre os grupos. Na análise do Escore de Meningite Bacteriana, dos 338 pacientes com possível meningite asséptica (culturas negativas), 121 deles tiveram um ou mais pontos para o Escore de Meningite Bacteriana, com valor de sensibilidade de 100%, especificidade de 64,2% e valor preditivo negativo de 100%. Dos 121 pacientes com Escore de Meningite Bacteriana positivo, 71% (86 pacientes) tiveram a pesquisa de enterovírus positiva no líquido cefalorraquidiano. Conclusão A pesquisa de enterovírus no líquido cefalorraquidiano mostrou-se eficaz em diferenciar a meningite bacteriana da viral. Analisada junto com o Escore de Meningite Bacteriana, a especificidade foi maior em comparação ao Escore de Meningite Bacteriana isolado.

Prevalência de conjuntivite adenoviral em clínica oftalmológica no município de Viçosa (MG) / Prevalence of adenoviral conjunctivitis at the ophthalmologic clinic on municipality of Viçosa/MG

Objetivo: Avaliar a prevalência de Adenovírus como agente etiológico da conjuntivite, em clínica médica oftalmológica especializada, em Viçosa, Minas Gerais, Brasil. Métodos: Amostras da secreção conjuntival de 91 pacientes clinicamente diagnosticados com conjuntivite foram submetidos à reação em cadeia da polimerase (PCR), utilizando primers degenerados para a região codificadora do gene da proteína estrutural II. Posteriormente as amostras positivas foram submetidas a sequenciamento e genotipagem. Resultados: A análise dos resultados de PCR revelou prevalência de 36,3% de Adenovírus. Não havendo distinção entre os sexos e com maior prevalência na faixa etária de 26 a 65 anos com 60,60% dos casos positivos. O sequenciamento dos casos positivos por Adenovírus revelaram a presença dos sorotipos 3, 4, 7, 8 e 34 circulante na região. Conclusão: No município de Viçosa, dois em cada cinco casos de conjuntivite são de etiologia adenoviral.

Objective: The aim of this study was to evaluate the prevalence of Adenovirus as a etiologic agent of conjunctivitis on a ophthalmic clinic in Viçosa, Minas Gerais, Brazil. Methods: Samples of conjunctival secretion from 91 patients clinically diagnosed with conjunctivitis were subjected to polymerase chain reaction (PCR) using degenerate primers targeted to the gene encoding the structural protein II. Positive samples were subsequently subjected to sequencing and genotyping. Results: PCR results showed 36.3% prevalence of Adenovirus. No differences between the sexes and was found to be higher in the age group 26-65 years with 60.60% of the positive cases. Sequencing of positive cases showed the presence of Adenovirus serotypes 3, 4, 7, 8, and 34 circulating in the region. Conclusion: In Viçosa two in five cases of conjunctivitis has Adenovirus as etiologic agent.

Frequency of viral etiology in symptomatic adult upper respiratory tract infections

Aims: To determine the frequency of viral pathogens causing upper respiratory tract infections in non-hospitalized, symptomatic adults in the city of Rio de Janeiro. Methods: Respiratory samples (nasal/throat swabs) were collected between August 2010 and November 2012 and real time PCR was used to detect different viral pathogens. Results: Viruses were detected in 32.1% (43/134) of samples from 101 patients. Specifically, 9% (12/134) were positive for HBoV, 8.2% (11/134) were positive for HAdV, 5.2% (7/134) were positive for HRV, and 1.5% (2/134) were positive for FLUBV or HMPV, as single infections. HRSV-A, HPIV-3, and HCoV-HKU1 were detected in one (0.75%) sample each. Co-infections were detected in 4.8% (6/134) of the samples. Peaks of viral infections were observed in March, April, May, August, and October. However, positive samples were detected all year round. Only 23.3% (10/43) of the positive samples were collected from patients with febrile illness. Conclusion: Results presented in this report suggest that respiratory viral infections are largely under diagnosed in immunocompetent adults. Although the majority of young adult infections are not life-threatening they may impose a significant burden, especially in developing countries since these individuals represent a large fraction of the working force. .

Application of hexon gene sequencing of adenovirus in pathogen detection of epidemic keratoconjunctivitis / 中华实验眼科杂志

Background Epidemic keratoconjunctivitis is a common eye disease,and adenovirus is one of the common pathogens.The hexon protein,one main capsid protein of the virus,is an important target of antibody binding.Thus,sequencing the coding region of the hexon protein is an important way for adenovirus fast typing.Objective This study was to complete a molecular epidemiology survey of epidemic keratoconjunctivitis and investigate its association with adenovirus in Shanghai area by sequencing the coding region of hexon protein.Methods Two hundred and fourteen sacconjunctival swab specimens were collected from 214 patients with suspicious epidemic keratoconjunctivitis who visited Shanghai Eye Disease Prevention and Treatment Center and the clinical sites supervised by the Shanghai Prevention and Monitoring Office of Acute Hemerragic Conjunctivitis under the informed consent from January 2010 to December 2012.DNA was extracted from the specimens and then the 140 bp conserved sequence in hexon protein coding region was amplified by PCR initially to determine an adenovirus pathogen.Furtherly,956 bp conserved sequence of the hexon codind district was sequencied to clarify the serotype of adenovirus in the adenovirus-positive specimens.Results 50.93％ patients (109/214) were detected to be adenovirus-positive by generic PCR,in which AdV1 + was in 4 patiens,AdV2+ was in 33 patients,AdV3+ was in 15 patients,AdV4+ was in 12 patients,AdV8+ was in 19 patiens,AdV19+ was in 15 patients,AdV37+ was in 8 patients.The subgenus D adenoviruses,including AdV8+,AdV19+ and AdV37+ often resulted in corneal inflammation,pseudomembranous conjunctivitis and preauricular lymph nodes;while subgenus B adenovirus induced much frequent tract infection and less corneal response.Conclusions PCR-sequence of conserved region of hexon protein coding district is applicable for the detection and serotyping of adenovirus in epidemic keratoconjunctivitis.

Acute respiratory viral infections in children in Rio de Janeiro and Teresópolis, Brazil / Infecções respiratórias agudas causadas por vírus em crianças do Rio de Janeiro e de Teresópolis, Brasil

The frequency of viral pathogens causing respiratory infections in children in the cities of Rio de Janeiro and Teresópolis was investigated. Nasal swabs from children with acute respiratory illnesses were collected between March 2006 and October 2007. Specimens were tested for viral detection by conventional (RT)-PCR and/or real time PCR. Of the 205 nasal swabs tested, 64 (31.2%) were positive for at least one of the viral pathogens. Single infections were detected in 56 samples, 50 of those were caused by RNA viruses: 33 samples tested positive for rhinovirus, five for influenza A, five for metapneumovirus, four for coronavirus and, three for respiratory syncytial virus. For the DNA viruses, five samples were positive for bocavirus and one for adenovirus. Co-infections with these viruses were detected in eight samples. Our data demonstrate a high frequency of viral respiratory infections, emphasizing the need for a more accurate diagnosis particularly for the emerging respiratory viruses. The fact that the emerging respiratory viruses were present in 9.2% of the tested samples suggests that these viruses could be important respiratory pathogens in the country.

Neste estudo foi investigada a frequência de patógenos virais causando infecção em crianças nas cidades do Rio de Janeiro e Teresópolis. Foram coletados 205 swabs nasais de crianças com infecção aguda do trato respiratório no período de março de 2006 a outubro de 2007. Os espécimes foram testados para detecção de vírus através de (RT)-PCR e/ou PCR em tempo real. Dentre as 205 amostras testadas, 64 (31,2%) foram positivas para pelo menos um vírus. Infecções causadas por um único agente viral foram detectadas em 56 amostras, 50 das quais eram causadas por vírus de RNA: 33 amostras foram positivas para rinovírus, cinco amostras foram positivas para influenza A, cinco amostras foram positivas para metapneumovírus, quatro amostras foram positivas para coronavírus e três amostras foram positivas para vírus respiratório sincicial. Para os vírus de DNA foram detectadas cinco amostras positivas para bocavírus humano e uma amostra positiva para adenovírus. Foram identificados oito casos de co-infecção. Nossos dados demonstram frequência elevada de infecções respiratórias virais, enfatizando a necessidade de um diagnóstico mais acurado destes patógenos, principalmente os vírus considerados emergentes. O fato de alguns vírus respiratórios emergentes terem sido detectados em 9,2% das amostras testadas sugere que estes vírus podem ser patógenos respiratórios importantes no país.

Broad reactive monoclonal antibodies for rapid identification of enteroviruses show cross-reactivity with chikungunya virus infected cells

In the past decade, enterovirus 71 (EV71) and chikungunya (CHIK) virus have re-emerged periodically causing serious public health problems in Malaysia, since their first emergence in 1997 and 1998 respectively. This study demonstrates that CHIK virus causes similar patterns of cytopathic effect in cultured Vero cells as some enteroviruses. They also show positive cross-reaction on direct immunofl uorescence staining using monoclonal antibodies meant for typing enteroviruses. Without adequate clinical and epidemiological information for correlation, CHIK virus isolated from patients with acute febrile rash can be wrongly reported as untypeable enterovirus due to its cross-reactivity with commercial pan-enterovirus monoclonal antibodies. This is due to the diagnostic laboratory being unaware of such cross-reactions as it has not been reported previously. Final identifi cation of the virus could be determined with specific antibodies or molecular typing using specifi c oligonucleotide primers for the CHIK virus.

Nucleic Acid Sequence-Based Amplification and Its Applications in Viral Diagnosis / 中国生物工程杂志

Nucleic acid sequence-based amplification(NASBA) is a sensitive,isothermal,transcription-based amplification system specifically designed for the detection of RNA targets,which could amplify templete RNA in 2h under isothermal condition at about 42?C and without any special equipment.NASBA is now widely applicated in diagnosis of many pathogenic microorganism.It is mainly about principles and applications of NASBA in viral diagnosis.