RESUMO
To better understand the significant variability displayed by influenza viruses, we need to be aware not only of its genetic characteristics, but also of the effect this genetic makeup has on proteins associated with viral replication and antigenicity. The origin of such diversity is due first and foremost to its segmented genome that allows segment reassortment (antigenic shift) and second to the error prone viral polymerase (antigenic drift) responsible of copying the genes enclosed in these segments. These two combined mechanisms confer a genetic plasticity that often leads to the emergence of new influenza viruses in nature.
Assuntos
Farmacorresistência Viral/genética , Variação Genética , Orthomyxoviridae/genética , Tropismo Viral , Animais , Variação Antigênica , Genoma Viral , Humanos , Alphainfluenzavirus/efeitos dos fármacos , Alphainfluenzavirus/genética , Betainfluenzavirus/genética , Gammainfluenzavirus/genética , Mutação , Replicação Viral , Eliminação de Partículas ViraisRESUMO
Several studies conducted all over the world have reported that the influenza virus is associated with great morbidity and mortality rates. In this study, we analyzed the incidence of the influenza virus between 2000 and 2003 in Curitiba. We studied 1621 samples obtained from outpatients and hospitalized patients of both sexes and all ages. The study was conducted at the local primary care health units (outpatients) and at the tertiary care unit (hospitalized) of the General Hospital of the Federal University in the state of Paraná, Brazil. Nasopharyngeal aspirates and, eventually, bronchoalveolar lavage were assayed for the presence of viral antigens, either by indirect immunofluorescence or cell culture. Of the samples studied, 135 (8.3%) were positive for influenza virus, and of those, 103 (76.3%) were positive for type A and 32 (23.7%) for type B. Additionally, positive samples were analyzed by reverse transcription followed by polymerase chain reaction and subtypes H1 and H3 were identified from this group. A high incidence of positive samples was observed mainly in the months with lower temperatures. Furthermore, outpatients showed a higher incidence of influenza viruses than hospitalized patients.
Assuntos
Alphainfluenzavirus/imunologia , Antígenos Virais/sangue , Betainfluenzavirus/imunologia , Influenza Humana/epidemiologia , Brasil/epidemiologia , Líquido da Lavagem Broncoalveolar/virologia , Técnicas de Cultura de Células , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Incidência , Influenza Humana/diagnóstico , Influenza Humana/virologia , Alphainfluenzavirus/genética , Betainfluenzavirus/genética , Masculino , Líquido da Lavagem Nasal/virologia , Vigilância da População , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estações do AnoRESUMO
Several studies conducted all over the world have reported that the influenza virus is associated with great morbidity and mortality rates. In this study, we analyzed the incidence of the influenza virus between 2000 and 2003 in Curitiba. We studied 1621 samples obtained from outpatients and hospitalized patients of both sexes and all ages. The study was conducted at the local primary care health units (outpatients) and at the tertiary care unit (hospitalized) of the General Hospital of the Federal University in the state of Paraná, Brazil. Nasopharyngeal aspirates and, eventually, bronchoalveolar lavage were assayed for the presence of viral antigens, either by indirect immunofluorescence or cell culture. Of the samples studied, 135 (8.3 percent) were positive for influenza virus, and of those, 103 (76.3 percent) were positive for type A and 32 (23.7 percent) for type B. Additionally, positive samples were analyzed by reverse transcription followed by polymerase chain reaction and subtypes H1 and H3 were identified from this group. A high incidence of positive samples was observed mainly in the months with lower temperatures. Furthermore, outpatients showed a higher incidence of influenza viruses than hospitalized patients.