Epidemiological aspects of influenza A related to climatic conditions during and after a pandemic period in the city of Salvador, Northeastern Brazil.
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.
Laboratório de Pesquisa em Infectologia, Complexo Hospitalar Professor Edgard Santos.
Rosangela de Castro
Rde C
Silva
Laboratório de Vírus Respiratório e Influenza, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brasil.
Marilda Agudo Mendonça
MA
Siqueira
Laboratório de Pesquisa em Infectologia, Complexo Hospitalar Professor Edgard Santos.
Eduardo Martins
EM
Netto
Laboratório de Pesquisa em Infectologia, Complexo Hospitalar Professor Edgard Santos.
Jacione Silva
JS
Bastos
Departamento de Pediatria, Faculdade de Medicina da Bahia.
Cristiana Maria
CM
Nascimento-Carvalho
Universidade Federal da Bahia, Salvador, BA, Brasil.
Ana Luisa
AL
Vilas-Boas
Universidade Federal da Bahia, Salvador, BA, Brasil.
Maiara Lana
ML
Bouzas
Laboratório de Vírus Respiratório e Influenza, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brasil.
Fernando do Couto
Fdo C
Motta
Laboratório de Pesquisa em Infectologia, Complexo Hospitalar Professor Edgard Santos.
Carlos
C
Brites
D000256:Adenoviridae / Q000302:isolation & purification; D001938:Brazil / Q000453:epidemiology; D002675:Child, Preschool; D055907:Climatic Processes; D060085:Coinfection; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification* / Q000502:physiology; D053122:Influenza A Virus, H3N2 Subtype / Q000302:isolation & purification* / Q000502:physiology; D009981:Influenza B virus / Q000302:isolation & purification* / Q000502:physiology; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D017817:Nasal Lavage Fluid / Q000821:virology; D058873:Pandemics; D011891:Rain / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification; D018108:Respirovirus / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D017421:Sequence Analysis; D013472:Sunlight; D019562:Viral Load; D014887:Weather