RESUMO
Novel H1N2 and H3N2 swine influenza A viruses (IAVs) were identified in commercial farms in Chile. These viruses contained H1, H3 and N2 sequences, genetically divergent from IAVs described worldwide, associated with pandemic internal genes. Guinea pigs were used as human surrogate to evaluate the infection dynamics of these reassortant viruses, compared with a pandemic H1N1 virus. All viruses replicated and were shed in the upper respiratory tract without prior adaptation although H1N2 viruses showed the highest shedding titers. This could have public health importance, emphasizing the need to carry out further studies to evaluate the zoonotic potential of these viruses.
Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A Subtipo H1N2/fisiologia , Vírus da Influenza A Subtipo H3N2/fisiologia , Infecções por Orthomyxoviridae/veterinária , Animais , Cobaias , Vírus da Influenza A Subtipo H1N2/genética , Vírus da Influenza A Subtipo H3N2/genética , Infecções por Orthomyxoviridae/virologia , Filogenia , Vírus Reordenados/genética , Vírus Reordenados/fisiologia , Análise de Sequência de RNA/veterináriaRESUMO
BACKGROUND: Avian influenza A viruses can cross naturally into mammals and cause severe diseases, as observed for H5N1. The high lethality of human infections causes major concerns about the real risk of a possible pandemic of severe diseases to which human susceptibility may be high and universal. High hydrostatic pressure (HHP) is a valuable tool for studies regarding the folding of proteins and the assembly of macromolecular structures such as viruses; furthermore, HHP has already been demonstrated to promote viral inactivation. METHODS: Here, we investigated the structural stability of avian and human influenza viruses using spectroscopic and light-scattering techniques. We found that both particles have similar structural stabilities and that HHP promotes structural changes. RESULTS: HHP induced slight structural changes to both human and avian influenza viruses, and these changes were largely reversible when the pressure returned to its initial level. The spectroscopic data showed that H3N2 was more pressure-sensitive than H3N8. Structural changes did not predict changes in protein function, as H3N2 fusion activity was not affected, while H3N8 fusion activity drastically decreased. The fusion activity of H1N1 was also strongly affected by HHP. In all cases, HHP caused inactivation of the different influenza viruses. CONCLUSIONS: HHP may be a useful tool for vaccine development, as it induces minor and reversible structural changes that may be associated with partial preservation of viral biological activities and may potentiate their immunogenic response while abolishing their infectivity. We also confirmed that, although pressure does not promote drastic changes in viral particle structure, it can distinctly affect viral fusion activity.
Assuntos
Vírus da Influenza A/química , Animais , Guanidina/química , Humanos , Pressão Hidrostática , Vírus da Influenza A Subtipo H1N1/química , Vírus da Influenza A Subtipo H1N1/fisiologia , Vírus da Influenza A Subtipo H3N2/química , Vírus da Influenza A Subtipo H3N2/fisiologia , Vírus da Influenza A Subtipo H3N8/química , Vírus da Influenza A Subtipo H3N8/fisiologia , Vírus da Influenza A/fisiologia , Temperatura , Ureia/química , Vacinas/imunologia , Inativação de VírusRESUMO
During the influenza pandemic of 2009, the A(H1N1)pdm09, A/H3N2 seasonal and influenza B viruses were observed to be co-circulating with other respiratory viruses. To observe the epidemiological pattern of the influenza virus between May 2009-August 2011, 467 nasopharyngeal aspirates were collected from children less than five years of age in the city of Salvador. In addition, data on weather conditions were obtained. Indirect immunofluorescence, real-time transcription reverse polymerase chain reaction (RT-PCR), and sequencing assays were performed for influenza virus detection. Of all 467 samples, 34 (7%) specimens were positive for influenza A and of these, viral characterisation identified Flu A/H3N2 in 25/34 (74%) and A(H1N1)pdm09 in 9/34 (26%). Influenza B accounted for a small proportion (0.8%) and the other respiratory viruses for 27.2% (127/467). No deaths were registered and no pattern of seasonality or expected climatic conditions could be established. These observations are important for predicting the evolution of epidemics and in implementing future anti-pandemic measures.
Assuntos
Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/isolamento & purificação , Influenza Humana/epidemiologia , Estações do Ano , Tempo (Meteorologia) , Adenoviridae/isolamento & purificação , Brasil/epidemiologia , Pré-Escolar , Processos Climáticos , Coinfecção , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Lactente , Recém-Nascido , Vírus da Influenza A Subtipo H1N1/fisiologia , Vírus da Influenza A Subtipo H3N2/fisiologia , Vírus da Influenza B/fisiologia , Influenza Humana/virologia , Líquido da Lavagem Nasal/virologia , Pandemias , Chuva/virologia , Vírus Sinciciais Respiratórios/isolamento & purificação , Respirovirus/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência , Luz Solar , Carga ViralRESUMO
BACKGROUND: Influenza viruses cause highly contagious acute respiratory illnesses with significant mortality, especially among young children, elderly people, and individuals with serious medical conditions. This encourages the development of new treatments for human flu. Biotherapies are diluted solutions prepared from biological products compounded following homeopathic procedures. OBJECTIVES: To develop a biotherapy prepared from the infectious influenza A virus (A/Aichi/2/68 H3N2) and to verify its in vitro response. METHODS: The ultradiluted influenza virus solution was prepared in the homeopathic dilution 30dH, it was termed Influenzinum RC. The cellular alterations induced by this preparation were analyzed by optical and electron microscopy, MTT and neutral red assays. Glycolytic metabolism (PFK-1) was studied by spectrophotometric assay. Additionally, the production of tumor necrosis factor-α (TNF-α) by J774.G8 macrophage cells was quantified by ELISA before and after infection with H3N2 influenza virus and treatment. RESULTS: Influenzinum RC did not cause cytotoxic effects but induced morphological alterations in Madin-Darby canine kidney (MDCK) cells. After 30 days, a significant increase (p < 0.05) in mitosis rate was detected compared to control. MDCK mitochondrial activity was changed after treatment for 10 and 30 days. Treatment significantly diminished (p < 0.05) PFK-1 activity. TNF-α in biotherapy-stimulated J774.G8 macrophages indicated a significant (p < 0.05) increase in this cytokine when the cell supernatant was analyzed. CONCLUSION: Influenzinum RC altered cellular and biochemical features of MDCK and J774G8 cells.
Assuntos
Homeopatia/métodos , Vírus da Influenza A Subtipo H3N2/fisiologia , Animais , Terapia Biológica , Linhagem Celular/virologia , Cães , Técnicas de Diluição do Indicador , Macrófagos/metabolismo , Microscopia Eletrônica , Mitose , Fosfofrutoquinase-1/metabolismo , Soluções/análise , Espectrofotometria , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The trends of influenza infection in Suriname were assessed from February 2010 through February 2011. Testing of 393 patients with symptoms of acute respiratory infection (ARI) revealed 15.3% Influenza B and 18.6% could be identified as influenza A positive, consisting of 56% influenza A(H1N1)pdm09 and 44% seasonal A(H3N2). Influenza infection occurred throughout the year, and all three influenza types affected young children as the primary population. The annual incidence of A(H1N1)pdm09 was 6.88 per 100,000 inhabitants [CI] 4.87-9.45. The spread of influenza could neither be linked to tourist flow from the Netherlands nor to contact rates related to school schedules.