Genetic variation characteristics of HA gene of influenza A virus (H3N2) in Guizhou province from 2017 to 2019 / 中国基层医药

Objective:To analyze the genetic variation characteristics of the HA gene of influenza A virus (H3N2) in Guizhou province from 2017 to 2019. Methods:Twenty strains of influenza A virus (H3N2) were randomly selected from 10 network laboratories in Guizhou province for RNA extraction. Reverse transcriptase-polymerase chain reaction and sequencing were performed. The products were analyzed using bioinformatics software.Results:The nucleotide homology of the HA gene of the 20 strains was 97.7%-100%, which was highly homologous to the vaccine strains A/Hong-Kong/4801/2014 recommended by WHO in 2017 and A/Singapore-INFIMH/16-0019/2016 recommended by WHO in 2018, but they were significantly different from the vaccine strain A/Kansas/14/2017 recommended by WHO in 2019. Genetic analysis showed that the 20 strains were divided into two branches, and the strains that were prevalent in 2019 were located in different branches, with marked genetic differences. Key site analysis showed mutations in antigenic determinants A, B, C, and E and mutations in the anterior and posterior walls of receptor binding sites. Key site analysis also showed that there was an increase in the number of glycosylation sites compared with the vaccine strains prevalent in the same year. Genetic distance, antigen sites, and glycosylation sites were slightly different between virus strains prevalent in 2017-2018 and virus strains prevalent in 2019. Conclusion:The HA gene of the influenza A virus subtype H3N2 in Guizhou province from 2017 to 2019 showed heterogeneity and gene mutation, especially in 2019. Therefore, close monitoring of the genetic evolution of the influenza A virus subtype H3N2 is necessary.

Influenza A(H3N2) infection followed by separate COVID-19 infection / Infección por el virus de la gripe A (H3N2) seguida de infección separada por el virus causante de la COVID-19 / Infecção por influenza A (H3N2) seguida de infecção independente por COVID-19

ABSTRACT This study describes the case of a health professional infected first by influenza virus A(H3N2) and then by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 11 days later. Respiratory samples and clinical data were collected from the patient and from close contacts. RNA was extracted from samples and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to investigate the viruses. The patient presented with two different illness events: the first was characterized by fever, chest and body pain, prostration and tiredness, which ceased on the ninth day; RT-qPCR was positive only for influenza virus A(H3N2). Eleven days after onset of the first symptoms, the patient presented with sore throat, nasal congestion, coryza, nasal itching, sneezing and coughing, and a second RT-qPCR test was positive only for SARS-CoV-2; in the second event, symptoms lasted for 11 days. SARS-CoV-2 sequencing identified the Omicron BA.1 lineage. Of the patient's contacts, one was coinfected with influenza A(H3N2) and SARS-CoV-2 lineage BA.1.15 and the other two were infected only with SARS-CoV-2, one also with Omicron BA.1.15 and the other with BA.1.1. Our findings reinforce the importance of testing for different viruses in cases of suspected respiratory viral infection during routine epidemiological surveillance because common clinical manifestations of COVID-19 mimic those of other viruses, such as influenza.

RESUMEN Este estudio describe el caso de un profesional de la salud que contrajo la infección primero por el virus de la gripe A (H3N2) y a continuación por el coronavirus 2 del síndrome respiratorio agudo grave (SARS-CoV-2) 11 días después. Se recogieron muestras respiratorias y datos clínicos del paciente y sus contactos cercanos. Se extrajo ARN de muestras y se utilizó la reacción en cadena de la polimerasa cuantitativa con transcripción inversa (RT-qPCR, por su sigla en inglés) para investigar los virus. El paciente presentó dos procesos infecciosos distintos: el primero se caracterizó por fiebre, dolor corporal y torácico, postración y cansancio, que cesó en el noveno día. La prueba mediante RT-qPCR solo fue positiva en el virus de la gripe A (H3N2). Once días después del inicio de los primeros síntomas, el paciente manifestó dolor de garganta, congestión nasal, catarro, picazón nasal, estornudos y tos. Una segunda prueba mediante RT-qPCR solo fue positiva para el SARS-CoV-2 y durante este segundo proceso los síntomas duraron 11 días. La secuenciación del SARS-CoV-2 identificó el linaje ómicron BA.1. De los contactos del paciente, uno presentaba una coinfección por el virus de la gripe A (H3N2) y el linaje BA.1.15 del SARS-COV-2, y los otros dos presentaban infecciones únicamente por SARS-CoV-2, uno también del linaje ómicron BA.1.15 y el otro de BA.1.1. Estos hallazgos refuerzan la importancia de realizar pruebas para detectar diferentes virus en casos de sospecha de infección viral respiratoria durante la vigilancia epidemiológica de rutina porque las manifestaciones clínicas comunes de COVID-19 son similares a las de otros virus, como en el caso de la gripe.

RESUMO Este estudo descreve o caso de uma profissional de saúde infectada primeiro pelo vírus influenza A (H3N2) e, 11 dias depois, pelo coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2). Amostras respiratórias e dados clínicos foram coletados da paciente e de contatos próximos. RNA foi extraído das amostras, e o método de reação em cadeia da polimerase via transcriptase reversa quantitativa (RT-qPCR) foi utilizado para investigar os vírus. A paciente apresentou dois quadros clínicos distintos. O primeiro foi caracterizado por febre, dor no peito e no corpo, prostração e fadiga, que cessou no nono dia. A RT-qPCR foi positiva apenas para o vírus da influenza A (H3N2). Onze dias após o início dos primeiros sintomas, a paciente apresentou dor de garganta, congestão nasal, coriza, prurido nasal, espirros e tosse. Um segundo teste de RT-qPCR foi positivo apenas para SARS-CoV-2. No segundo evento, os sintomas duraram 11 dias. O sequenciamento do SARS-CoV-2 identificou a cepa Ômicron BA.1. Dentre os contatos da paciente, um teve coinfeção por influenza A (H3N2) e SARS-COV-2 (cepa BA.1.15), e os outros dois foram infectados apenas por SARS-CoV-2 (um também pela cepa Ômicron BA.1.15 e o outro pela BA.1.1). Nossos achados reforçam a importância de testes para a detecção de diferentes vírus em casos de suspeita de infecção viral respiratória durante a vigilância epidemiológica de rotina, visto que as manifestações clínicas comuns da COVID-19 imitam as de outros vírus, como o vírus influenza.

Molecular evolution of influenza A/H3N2 viruses HA and NA genes circulating in Shenzhen in 2017 / 中华疾病控制杂志

Objective To investigate the molecular evolution of the Hemagglutinin (HA) and Neuraminidase (NA) genes of influenza A/H3N2 viruses in Shenzhen in the first half of 2017, so as to provide scientific basis for predicating influenza epidemic and variation. Methods A total of 40 influenza A/H3N2 viruses strains were selected and the molecular phylogenetic trees were constructed by bioinformatics software DNAStar, MEGA 7.0, etc. Then, the genetic characteristics and variation of HA and NA genes along with corresponding amino acids were analyzed. Results The homology of Shenzhen isolates reached 97.8%-100.0%, which located in the human-derived branch of Asia and North America. Compared with the vaccine strains A/Switzerland/9715293/2013(H3N2) and A/Hong Kong 14801/2014(H3N2) recommended by world Health Oraganication (WHO), there was a higher sequence similarity. Compared with the vaccine strain, HA and NA proteins had a number of amino acid sites replaced, of which HA 6 antigen sites and 2 receptor binding sites change; NA had a mutation of D151N/G located in enzyme activity sites. Potential N-glycosylation sites for HA and NA also changed. Conclusions The influenza A/H3N2 viruses in Shenzhen in the first half of 2017 has not yet formed a new subtype in the epidemic. Currently, the recommended vaccine strains still have some protective effects on the population. The replacement mutation of multiple amino acids sites of HA and NA suggests that the dynamic monitoring of molecular level of influenza A/H3N2 viruses need to be strengthened.

Evolution of influenza A(H3N2) virus hemagglutinin (HA1) gene in Shangluo, China, 2014-2015 / 中国人兽共患病学报

Comparative analysis of the variations in HA 1 gene of the influenza A (H3N2) virus and the vaccine recommended were conducted in Shangluo city of China,during the surveillance year of 2014-2015.In this study,we collected the samples of H3N2 subtype strain from the Shanglou City of China during the surveillance period of 2014-2015.The strain was cultured in MDCK cells,HA gene fragment was amplified by RT-PCR and the nucleotide sequence was determined.Sequence alignment was performed using the clustax2.1 software.The phylogenetic tree was constructed by Mega6.0 software and was analyzed by Neighboring-joining method.Results showed that the homology of isolated strain during 2014-2015 was 97.2 ％-99.9％ and homology with the recommended vaccine strain A/Texas/50/2012 was 97.3％-98.5％.The amino acid sequence of the HA 1 gene of the isolated strain was compared with that of the vaccine strain.The major antigenic determinants of the isolates in 2014,having mutations were section B,Y159F,S198P,while the major antigenic determinants of isolates in 2015,having amino acid mutations were A zone G142R,B region S159F,S198P.These results indicated that the key antigenic determinant of influenza H3N2 subtype strain in Shangluo City has changed in 2014-2015 and A/Texas/50/2012 vaccine component is no more effective.Hence,there is an urgent need to update the influenza H3N2 subtype vaccine components and in future we should be deeply concerned about the evolution ofinfluenza H3N2 gene trends.

Detección de virus influenza A, B y subtipos a (H1N1) pdm09, A (H3N2) por múltiple rt-pcr en muestras clínicas / Detection of influenza A, B and subtypes A (H1N1) pdm09, A (H3N2) viruses by multiple qrt-pcr in clinical samples

RESUMEN Objetivos. Estandarizar la técnica de reacción en cadena de la polimerasa en tiempo real (RT-PCR) múltiple para la detección de virus influenza A, B y tipificación de subtipos A (H1N1) pdm09, A (H3N2) en muestras clínicas. Materiales y métodos. Se analizaron 300 muestras de hisopado nasofaríngeo. Esta metodología fue estandarizada en dos pasos: la primera reacción detectó el gen de la matriz del virus de influenza A, gen de la nucleoproteína del virus influenza B y el gen GAPDH de las células huésped. La segunda reacción detectó el gen de la hemaglutinina de los subtipos A (H1N1) pandémico (pdm09) y A (H3N2). Resultados. Se identificaron 109 muestras positivas a influenza A y B, de las cuales 72 fueron positivas a influenza A (36 positivas a influenza A (H1N1) pdm09 y 36 positivos a influenza A (H3N2)) y 37 muestras positivas a influenza B. 191 fueron negativas a ambos virus mediante RT-PCR en tiempo real multiplex. Se encontró una sensibilidad y especificidad del 100% al analizar los resultados de ambas reacciones. El límite de detección viral fue del rango de 7 a 9 copias/µL por virus. Los resultados no mostraron ninguna reacción cruzada con otros virus tales como adenovirus, virus sincitial respiratorio, parainfluenza (1,2 y 3), metapneumovirus, subtipos A (H1N1) estacional, A (H5N2) y VIH. Conclusiones. La RT-PCR múltiple demostró ser una prueba muy sensible y específica para la detección de virus influenza A, B y subtipos A (H1N1, H3N2) y su uso puede ser conveniente en brotes estacionales.

ABSTRACT Objectives. To describe the clinical and epidemiological characteristics of patients diagnosed with epidermolysis bullosa (EB) at the Instituto Nacional de Salud (INSN) in Lima, Peru; a National Reference Center for this disease. Material and methods . Observational, descriptive and transversal study. We reviewed the clinical histories and laboratory tests of patients diagnosed with EB treated in INSN from 1993 to 2015. Results. 93 patients were registered. The average age was 7.9 ± 5.6 years; 53.8% (n = 50) were boys. Clinical forms corresponded to dystrophic EB with 41 (44.1%) cases, simple EB with 39 (41.9%) union EB cases with 8 (8.6%) and Kindler syndrome with 4 (4.3%) cases. The clinical form could not be identified in a case. A total of 48 cases (51.6%) came from Lima and Callao, and 45 cases (48.4%) from other provinces of the country. Extracutaneous manifestations involved gastrointestinal (44.1%), ocular (37.6%), odontogenic (87.1%), and nutritional (79.6%) involvement, as well as pseudosindactilia (16.1%). Chronic malnutrition (71.6%), acute malnutrition (17.6%) and anemia (62.4%) were found. Mortality corresponded to 6 cases (6.5%). Conclusions. 93 cases of EB were reported in INSN, the predominant clinical presentation was the dystrophic form.

Molecular characteristics of hemagglutinin gene of influenza A (H3N2) virus strains circulating in Jiangsu province, China, 2013-2014 / 中华微生物学和免疫学杂志

Objective To analyze the genetic characteristics and the evolution of the influenza A (H3N2) virus strains circulating in Jiangsu province between 2013 and 2014.Methods This study analyzed thirty-one representative strains of influenza A (H3N2) virus, which were isolated in different regions of Jiangsu province and during different time periods from 2013 to 2014.Results Genetic distances in nucleic acid and amino acid between a strain used for vaccine production (A/Texas/50/2012) and the 31 strains were 0.010 5 and 0.012 4.Similarities between them in nucleic acid and amino acid sequences were 97.9%-99.6% and 97.2%-99.3%.Phylogenetic analysis showed that the hemagglutinin (HA) genes of the 31 strains were divided into three different groups.Three strains isolated in 2013 and three strains isolated in 2014 belonged to Group 1 and Group 2, respectively, while the others belonged to Group 3.Three positive selection sites (237, 366 and 367) in HA protein were observed by REL model.Compared with the strain used for vaccine production, the 31 strains were characterized by amino acid substitutions (N128A/T and P198S/A) in HA protein and all of the mutations located in B-cell epitopes.The total number of mutation sites reached 24.Compared with the A/Texas/50/2012 strain, seven strains presented the glycosylation site 126NWT, and three strains showed disappeared glycosylation sites of 45NSS and 144NNS.Evaluation of vaccine efficacy for A(H3N2) virus strains showed that the vaccine efficacy was not very well.Conclusion The HA gene of A(H3N2) virus had undergone a greater variation and the vaccine efficacy was not very well in Jiangsu province during 2013 to 2014, which made the influenza A(H3N2) virus become the circulating strain.

Influenza virus vaccine for neglected hosts: horses and dogs

This study provides information regarding vaccine research and the epidemiology of influenza virus in neglected hosts (horses and dogs). Equine influenza virus (EIV) causes a highly contagious disease in horses and other equids, and outbreaks have occurred worldwide. EIV has resulted in costly damage to the horse industry and has the ability of cross the host species barrier from horses to dogs. Canine influenza is a virus of equine or avian origin and infects companion animals that live in close contact with humans; this results in possible exposure to the seasonal epizootic influenza virus. There have been case reports of genetic reassortment between human and canine influenza viruses, which results in high virulence and the ability of transmission to ferrets. This emphasizes the need for vaccine research on neglected hosts to update knowledge on current strains and to advance technology for controlling influenza outbreaks for public health.

Protective efficacy of a high-growth reassortant swine H3N2 inactivated vaccine constructed by reverse genetic manipulation

Novel reassortant H3N2 swine influenza viruses (SwIV) with the matrix gene from the 2009 H1N1 pandemic virus have been isolated in many countries as well as during outbreaks in multiple states in the United States, indicating that H3N2 SwIV might be a potential threat to public health. Since southern China is the world's largest producer of pigs, efficient vaccines should be developed to prevent pigs from acquiring H3N2 subtype SwIV infections, and thus limit the possibility of SwIV infection at agricultural fairs. In this study, a high-growth reassortant virus (GD/PR8) was generated by plasmid-based reverse genetics and tested as a candidate inactivated vaccine. The protective efficacy of this vaccine was evaluated in mice by challenging them with another H3N2 SwIV isolate [A/Swine/Heilongjiang/1/05 (H3N2) (HLJ/05)]. Prime and booster inoculation with GD/PR8 vaccine yielded high-titer serum hemagglutination inhibiting antibodies and IgG antibodies. Complete protection of mice against H3N2 SwIV was observed, with significantly reduced lung lesion and viral loads in vaccine-inoculated mice relative to mock-vaccinated controls. These results suggest that the GD/PR8 vaccine may serve as a promising candidate for rapid intervention of H3N2 SwIV outbreaks in China.

Laboratory diagnosis and genetic characterization analysis of the subtype A3 influenza viruses in Quanzhou / 中华检验医学杂志

Objective To obtain the information of the 2009 influenza outbreak and the variations of influenza virus strains in quanzhou, and explore the relationship between the genetic variation of influenza virus and influenza epidemic. Methods During the influenza outbreak in quanzhou,one hundred and ninetyeight throat swabs specimens from the patients with influenza were collected. Viruses were isolated with MDCK cells and identified with serological test, followed by real-time RT-PCR. RNA of four influenza virus strains were extracted, then HA1 gene was amplified by RT-PCR. The purified PCR products were sequenced. The data were analyzed with the software DNAstar megalign. Results Total 98 pieces of H3N2 subtype influenza virus nucleic acid were detected in 198 throat swabs specimens,among which 62 influenza virus strains were identified as subtype influenza A( H3N2 ). The sequencing results of HA1 gene in these positive strains showed that their genetic characterization were more closed to strains A/Ningbo/333/2008 with a nucleotide homology of 98.7%, which was 96.8% as compared with A/Xiamen/70/2004. The amino acids sequences deduced from the nucleotide sequences in HA1 region of the isolated strain had 7 mutant sites compared with A/Brisbane/10/2007 vaccine strain. One variant amino acids were found located in the antigenic determinant sites A( 144 ), two were in the sites B( 158,189 ). Phylogenetic analysis also confirmed the difference in HAl domain. Conclusion The influenza virus strains causing the flu outbreak among some communities of quanzhou in 2009 are subtype influenza A ( H3N2 ), whose genetic characterization and antigenicity were different from the vaccine strain.

Analysis of levels of antibodies against influenza A virus of population in Shanghai during 2009 / 中华传染病杂志

Objective To know the levels of antibodies against influenza A virus subtypes H1 and H3 of population in Shanghai during 2009, and the detection of antibodies against avian influenza virus subtypes H5 and H9 in population which contacts with avian. Methods The serological survey of the antibodies against influenza A viruses subtypes H1, H3, H5 and H9 in 356 close contacts with avian (professional population) and 332 general subjects (general population) at various age groups were carried out using hemagglutinin inhibit (HI) test. Results The positive rates of antibodies against influenza virus A/Brisbane/59/2007 (H1N1) in general population and professional population were 82.8% (275/332) and 73.9% (263/356), respectively; those of A/Brisbane/10/2007 (H3N2)were 50.6% (168/332) and 54.8% (195/356), respectively. The positive rate of antibodies against influenza virus A/Brisbane/59/2007 (H1N1 )was significantly higher than that of influenza A viruses subtype H3, which was consistent with etiological survey of influenza virus in Shanghai during 2008.The positive rates of antibodies against influenza A virus subtype H5 in professional population and general population were 4.2% (15/356) and 0.3% (1/332), respectively; those of influenza A virus subtype H9 were 34.6% (123/356) and 2.4% (8/332), respectively. The positive rates of antibodies against influenza virus A/Brisbane/59/2007 (H1N1 ) and A/Brisbane/10/2007 (H3N2) in age groups of 6 months-5 years and ≥60 years were lower than other age groups. Conclusions The immune protective response against seasonal influenza A subtype H1 and H3 of population in Shanghai is high,while those of children and the elders were low. The levels of antibodies against influenza A viruses subtype H5 and H9 in professinal population present obviously ascending trend, which indicates that the etiological and serological survey of influenza virus in this population should be enhanced.

Evolutionary characterization of HA1 gene of influenza A H3N2 viruses from 2003 to 2008 in Hebei / 中华疾病控制杂志

Objective To understand the genetic characterization of HA1 gene of influenza A H3N2 viruses circulated in recent years in Hebei.Methods Viral RNAs of 25 H3N2 strains were extracted and amplified by Reverse Transcription Polymerase Chain Reaction (RT-PCR).The products of PCR were purified and sequenced,and the sequences were analyzed though biometic software.Results Several amino acid substitutions located in antigenic sites or receptor binding sites were found more in the isolates than the current vaccine virus or the isolates from previous year.Amino acid substitution was found in 3,140,142,144,145,158,159,189,192,193,198,204,225,226 and 227 positions in the isolates during 2003-2008,more amino acid substitutions took place in antigenic determinant A,B and receptor binding site (RBS).New phylogenetic branches appeared continuously during 2003-2008.The H3N2 strains of the same year almost clustered in the same group on the phylogenetic tree.Conclusions Amino acid substitutions continuously occurred in the HA1 genes in influenza A H3N2 viruses isolated in Hebei from 2003 to 2008,it is meaningful to pay close attention to the HA1 variation in order to prevent and control influenza.