RESUMO
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.
Assuntos
Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Vacinas contra Influenza/genética , Influenza Humana/virologia , Neuraminidase/genética , Filogenia , Proteínas Virais/genética , Sequência de Aminoácidos , Humanos , Vírus da Influenza A Subtipo H1N1/enzimologia , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vacinas contra Influenza/química , Vacinas contra Influenza/classificação , Vacinas contra Influenza/isolamento & purificação , Influenza Humana/epidemiologia , Irã (Geográfico)/epidemiologia , Dados de Sequência Molecular , Neuraminidase/química , Alinhamento de Sequência , Análise de Sequência de DNA , Proteínas Virais/químicaRESUMO
BACKGROUND: The 66 serotypes of human enteroviruses (EVs) are classified into four species A-D, based on phylogenetic relationships in multiple genome regions. Partial VP(1) amplification and sequence analysis are reliable methods for identifying non-polio enterovirus serotypes, especially in negative cell culture specimens from patients with residual paralysis. OBJECTIVES: In Iran during the years 2000-2002, there were 29 residual paralysis cases with negative cell (RD, HEp(2) and L(20)B) culture results. STUDY DESIGN: The genomic RNA was extracted from stool specimens from cases of residual paralysis and detected by amplification of the 5'-nontranslated region using RT-PCR with Pan-EV primers. Partial VP(1) amplification by semi-nested RT-PCR (snRT-PCR) and sequence analysis were done. RESULTS: Specimens from the 29 culture-negative cases contained echoviruses of six different serotypes. CONCLUSIONS: The global eradication of wild polioviruses is near and study of non-polio enteroviruses, which can cause poliomyelitis, is increasingly important to understand their pathogenesis. The VP(1) sequences, derived from the snRT-PCR products, allowed rapid molecular analysis of these non-polio strains.
Assuntos
Infecções por Enterovirus/complicações , Enterovirus/classificação , Enterovirus/isolamento & purificação , Paralisia/virologia , Adolescente , Criança , Pré-Escolar , Enterovirus/genética , Infecções por Enterovirus/virologia , Fezes/virologia , Feminino , Humanos , Lactente , Recém-Nascido , Irã (Geográfico) , Masculino , Reação em Cadeia da Polimerase , RNA Viral/genética , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Proteínas Estruturais Virais/genéticaRESUMO
BACKGROUND: The live-attenuated oral polio vaccine used to interrupt poliovirus transmission is genetically unstable. Reversion of some attenuating mutations, which normally occurs during vaccine strain replication in some recipients, and can rarely cause vaccine-associated paralytic poliomyelitis (VAPP). The poliovirus eradication program designed by the World Health Organization (WHO) includes immunization with OPV in addition to careful surveillance of all acute-flaccid paralysis (AFP) cases. OBJECTIVES: In Iran we last isolated imported wild poliovirus in 2000 and the immunization coverage was 100% in 2002. During 2001, there were three AFP cases with residual paralysis from which Sabin-like type 1 polioviruses were isolated in our national polio laboratory. STUDY DESIGN: The complete VP(1) region of the three isolates was sequenced and amino acid substitutions associated with these neurovirulent isolates were recorded. RESULTS: These isolates had either 4, 2 or 1 nucleotide substitution(s) in the VP(1) region, corresponding to amino acid change in the VP(1) of isolate 1 of either (H-[149]->Y), (T-[106]->A) or (I-[90]->L), respectively. CONCLUSIONS: Surveillance of the VAPP cases in countries where endemic transmission has recently ceased increases our understanding of the important neurovirulent mutations in vaccine-strain isolates and assists in planning the next step in the eradication program in these countries.
