RESUMEN
Prophylaxis of influenza A virus infections is based on the vaccines inducing antibodies to the major viral antigens, hemagglutinin (HA) and neuraminidase (NA). Since these antigens continuously change during virus replication in various hosts, only the currently circulating strains should be used in the vaccines. Besides, monitoring of the naturally occurring changes in HA, NA, and respective genes, especially those associated with resistance to the NA inhibitors is necessary. The NA genes of 30 Iranian isolates of influenza H1N1 virus from the seasons 2005-2009 were sequenced and subjected to the sequence and phylogenetic analyses. The seasonal isolates turned out to be closely related to the corresponding vaccine strains, except for the 2007-2008 isolates, which also displayed a higher nucleotide variation. A resistance to the NA inhibitors was found in the 2008-2009 isolates only. The average nucleotide identities of the isolates with corresponding vaccine strains for the years 2005-2009 were 98.83%, 98.55%, 98.7%, 97.55%, and 98.76%, respectively.
Asunto(s)
Subtipo H1N1 del Virus de la Influenza A/clasificación , Subtipo H1N1 del Virus de la Influenza A/genética , Vacunas contra la Influenza/genética , Gripe Humana/virología , Neuraminidasa/genética , Filogenia , Proteínas Virales/genética , Secuencia de Aminoácidos , Humanos , Subtipo H1N1 del Virus de la Influenza A/enzimología , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Vacunas contra la Influenza/química , Vacunas contra la Influenza/clasificación , Vacunas contra la Influenza/aislamiento & purificación , Gripe Humana/epidemiología , Irán/epidemiología , Datos de Secuencia Molecular , Neuraminidasa/química , Alineación de Secuencia , Análisis de Secuencia de ADN , Proteínas Virales/químicaRESUMEN
OBJECTIVES: To study the antigenic variations in influenza A/H3N2 viruses circulating in Iran for characterization and phylogenetic relationships to vaccine strains. METHODS: RT-PCR, full sequencing of hemagglutinin (HA) and neuraminidase (NA) genes and analysis by sequence handling and phylogenetic programs were done. RESULTS: The HA sequences of 2007 isolates fell within the clade represented by the HA of A/Brisbane/10/07 and characterized by the amino acid changes relative to the HA of A/Wisconsin/67/05, G50E and K140I. The only isolate in 2006 fell within A/Berlin/02/06 with V112I and K173E changes. The 2005 isolates characterized by Y159F, S189N and S227P changes within A/California/07/04. In all isolates we had E190D which is important because this was responsible for the loss of ability of A/H3N2 viruses to bind to chicken red blood cells. There were some substitutions in the antigenic sites of the HA. Similar to other studies, conserved residues for catalytic sites and also framework sites of NA supporting the catalytic residues were detected. We had some changes in the variable regions of the NA head domain. CONCLUSION: Comparison between Iranian viruses and vaccine strains showed high similarity between them and vaccine strains used in the northern hemisphere.
Asunto(s)
Hemaglutininas Virales/genética , Subtipo H3N2 del Virus de la Influenza A/genética , Vacunas contra la Influenza/genética , Gripe Humana/virología , Neuraminidasa/genética , Proteínas Virales/genética , Secuencia de Aminoácidos , Sustitución de Aminoácidos/genética , Análisis por Conglomerados , Humanos , Subtipo H3N2 del Virus de la Influenza A/aislamiento & purificación , Irán , Datos de Secuencia Molecular , Mutación Missense , Filogenia , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de SecuenciaRESUMEN
BACKGROUND: Respiratory virus infections in children are a leading cause of morbidity and mortality worldwide. METHODS: A total of 897 clinical specimens were collected from February 2007 to January 2008 and transported to the National Influenza Center. Two hundred and two samples belonged to children under the age of six from 897 specimens, described above, were selected. Then they were tested for influenza virus types and subtypes by real time PCR assay subsequently, the specimens were tested for RSV and hMPV by hemi-nested multiplex PCR and parainfluenza viruses type 1-4 by hemi-nested multiplex PCR and adenovirus by hemi-nested PCR. RESULTS: The throat swab was taken from the Kawasaki case with the history of chicken's contact. The specimen was tested for all influenza subtypes especially H5N1 and the results were negative. Meanwhile PCR was done for screening of other respiratory viruses that results came out positive for RSV and hMPV. CONCLUSION: In the present study, we demonstrated the possibility to detect dual infection caused by RSV and hMPV, but because of the extravagant pattern of this case, more investigation is suggested specially on Kawasaki patients.
RESUMEN
Adamantanes have been used for the prophylaxis and treatment of Influenza A virus (IAV) infections worldwide. However, they have limited use because of increasing number of resistant viruses during recent years. In investigating the frequency of amantadine-resistant IAVs (H3N2) circulating in Iran in 2005-2008, we found that M2 sequences of recently circulating viruses that were amantadine-resistant contained a Ser31Asn mutation. Thus, adamantanes should not be used for treatment or prophylaxis of recent IAVs (H3N2) infections. In future, their potential use will depend on the resistance of circulating viruses.