ABSTRACT
BACKGROUND: A retrospective cohort study, in the context of household transmission, to estimate the serial interval (SI) of pH1N1 influenza in the island of Tierra del Fuego was carried out. METHODS: We collected data from the epidemiological surveillance system during disease outbreak in Ushuaia and Rio Grande, the two main cities of the southernmost province of Argentina. Only the records of patients and households with a positive result of RT-PCR assay for pH1N1 virus were used. RESULTS: A total of 283 laboratory confirmed cases were detected, from 550 samples analyzed. Hospitalizations were necessary in 13.8% of patients, yet no deaths were reported. Complete data of household contacts were available in 13 patients. We calculated an SI of 2.0 days (95% CI = 1.5 - 2.6 days), fitting to a log-normal distribution, the one that presented the best adjustment. CONCLUSION: These results were consistent with estimates of SI calculated from Mexico, but lower than estimations from Canada, Germany and USA. We discuss these differences in relation to limitations of the current study design.
ABSTRACT
The aim of this study was to estimate the effectiveness of 2009 seasonal trivalent inactivated vaccine in reducing hospitalizations due to the novel influenza A H1N1 virus among positive cases. Data collected from Argentina's national epidemiological surveillance system were analyzed. All patients had a clinical diagnosis and underwent positive serological tests for pandemic influenza A H1N1. Logistic regression was used to estimate vaccine effectiveness to prevent severe cases of the disease, measured as hospitalizations. The adjusted effectiveness of the vaccine was 50% (95% CI: 40-59%). Vaccination was significantly associated with hospitalizations in all age groups, and within groups that had and had not received antiviral treatment. These results suggest that seasonal influenza vaccine might have conferred partial protection against severe cases due to the novel pandemic influenza.
Subject(s)
Disease Outbreaks/prevention & control , Hospitalization/statistics & numerical data , Influenza Vaccines/administration & dosage , Influenza, Human/prevention & control , Adolescent , Adult , Aged , Argentina/epidemiology , Child , Child, Preschool , Female , Humans , Influenza A Virus, H1N1 Subtype/immunology , Influenza, Human/epidemiology , Logistic Models , Male , Middle Aged , Sentinel Surveillance , Vaccines, Inactivated/administration & dosage , Young AdultABSTRACT
This study describes the first multicentered study of acute lower respiratory infection viral etiology in young children from four different geographical areas of Argentina. A total of 1,278 children under 5 years of age, hospitalized in primary care centers from Buenos Aires, Córdoba, Santa Fé and Mar del Plata cities during a 2-year period were studied (1993-1994). Nasopharyngeal aspirates were investigated for respiratory syncytial virus (RSV), adenovirus, parainfluenza, and influenza A and B viruses by indirect immunofluorescence. Out of the patients studied, 946 (74%) were under 1 year of age. Viruses were detected in 399 patients (32%). RSV was observed in 25.3% of the samples, representing 78.2% of all viral positive cases. Adenoviruses were detected in 2.5% of the cases, parainfluenza in 2.2%, influenza A in 2.1%, and influenza B in 0.2%. Compared with other viruses, the higher RSV frequency was statistically significant (P < 0.000). Most RSV cases were detected between May and September with a significant peak in July (P < 0.000). Pneumonia was observed in 46% of the patients, bronchiolitis in 41% and other entities in 13%. The case fatality rate observed during the 2 year study was 0.73%. Most of the above respiratory viruses were detected in the four cities, however, the frequency of RSV and influenza were different in the southern city.
Subject(s)
Respiratory Tract Infections/virology , Virus Diseases/virology , Acute Disease , Adenoviridae/isolation & purification , Ambulatory Care , Argentina , Bronchiolitis, Viral/epidemiology , Bronchiolitis, Viral/virology , Child, Preschool , Female , Humans , Infant , Influenza A virus/isolation & purification , Influenza B virus/isolation & purification , Male , Nasopharynx/virology , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , Pneumovirus/isolation & purification , Respiratory Syncytial Viruses/isolation & purification , Respiratory Tract Infections/epidemiology , Seasons , Virus Diseases/epidemiologyABSTRACT
This report describes findings from epidemiological surveillance of influenza virus in two cities in Argentina (Mar del Plata and Córdoba) from 1987 to 1993. It includes information on reporting and serologic characterization of isolated influenza viruses. In addition, determination was made of the nucleotide sequences of the HA1 subunits of five type A (subtype H3) viral strains isolated in the epidemics of 1990 and 1993. The incidence of illness, type of viruses isolated, and H gene sequences were similar to what has been reported from other parts of the world during the same period. The H3 strains isolated in the 1990 and 1993 seasons were somewhat removed in their molecular characteristics from the strains the World Health Organization recommended for vaccines for those years, and appeared closer to the strains recommended for vaccination in subsequent seasons.
Subject(s)
Influenza, Human/epidemiology , Orthomyxoviridae/isolation & purification , Argentina/epidemiology , Female , Humans , Influenza Vaccines , Influenza, Human/virology , Male , Population Surveillance , Vaccination , World Health OrganizationABSTRACT
The genes encoding the nucleoprotein, PB1, PB2, and PA proteins of the influenza virus strain B/Panamá/45/90 have been cloned under control of the T7 RNA polymerase promoter of plasmid pGEM-3. Transfection of the recombinant plasmids obtained into mammalian cells, which had been infected with a vaccinia virus encoding the T7 RNA polymerase, resulted in expression of the expected influenza B virus polypeptides. Moreover, it is shown that coexpression of the four recombinant core proteins in COS-1 cells reconstituted a functional polymerase capable of expressing a synthetic influenza B virus-like CAT RNA. By using the influenza B virus recombinant plasmids and a set of pGEM-derived plasmids encoding the homologous core proteins of the influenza A virus A/Victoria/3/75 (I. Mena et al. (1994). J. Gen. Virol. 75, 2109-2114), the capabilities of homo- and heterotypic mixtures of the four core proteins to express synthetic type A and B CAT RNAs were analyzed. Both the influenza A and B virus polymerases were active in expressing, albeit with reduced efficiencies, the heterotypic model CAT RNAs. However, none of all possible heterotypic mixtures of the core proteins reconstituted a functional polymerase. In order to fully characterize the recombinant plasmids obtained, the nucleotide sequences of the cloned genes were determined and compared to sequences of other type B virus isolates. The results obtained from these latter analyses are discussed in terms of the conservation and evolution of the influenza B virus core genes.
Subject(s)
DNA-Directed RNA Polymerases/genetics , Influenza B virus/genetics , Nucleoproteins , RNA-Dependent RNA Polymerase , Viral Core Proteins/genetics , Viral Proteins/genetics , Amino Acid Sequence , Animals , Base Sequence , COS Cells , Cloning, Molecular , DNA-Directed RNA Polymerases/biosynthesis , Molecular Sequence Data , Nucleocapsid Proteins , Recombinant Proteins/genetics , Viral Core Proteins/biosynthesis , Viral Proteins/biosynthesisABSTRACT
Ante la aparición de un foco en el Dto. El Carmen de la Pcia. de Jujuy a partir de Diciembre de 1992 el Instituto Nacional de Epidemiología, realizó un estudio de casos y controles a fin de proveer futuras situaciones epidémicas. Para ello se planteó como objetivo determinar la presencia de factores de riesgo vinculados con el agua, alimentos y el saneamiento y valorar su importancia en este brote. Se trabajó en conjunto con las autoridades del Hospital "Arturo Zabala" perteneciente al Area Programática III con cabecera en la Ciudad de Perico, que abarca las localidades de Puerto Viejo, Pampita, El Milagro, Aguas Calientes, Manantiales y Pampa Blanca. Se realizaron 73 encuestas y de las mismas al analizar los principales factores de riesgo surge : - Alta frecuencia de Ingesta de agua de acequia sin potabilizar (37,1 por ciento ), que está en relación a la falta de agua potable en el hogar (22,2 por ciento ) y en el lugar de trabajo (32,2 por ciento ). - Ingesta de frutas (47,9 por ciento ) y de verduras crudas (22,9 por ciento ) productos estos que pueden estar contaminados por el V. cholerae de acuerdo a su manipulación y riesgo. Del análisis estadístico de estos factores de riesgo surge como causa más significativa el consumo de agua de acequia sin potabilizar (O.R.=7,2:X=11,6:P<0,001). Analizando el riesgo atribuible poblacional para agua de acequia sin potabilizar nos indica que eliminando este factor, se podría disminuir la posibilidad de enfermar de cólera en un 70 por ciento aproximadamente, en el área estudiada. Esto reafirma que trabajando sobre los tres pilares fundamentales para el control y erradicación del cólera : calidad de agua, saneamineto del medio y educación para la salud, es posible el control de esta enfermedad
Subject(s)
Humans , Cholera/epidemiology , Disease Outbreaks/statistics & numerical data , Water Microbiology , Food Contamination , Case-Control Studies , ArgentinaABSTRACT
Ante la aparición de un foco en el Dto. El Carmen de la Pcia. de Jujuy a partir de Diciembre de 1992 el Instituto Nacional de Epidemiología, realizó un estudio de casos y controles a fin de proveer futuras situaciones epidémicas. Para ello se planteó como objetivo determinar la presencia de factores de riesgo vinculados con el agua, alimentos y el saneamiento y valorar su importancia en este brote. Se trabajó en conjunto con las autoridades del Hospital "Arturo Zabala" perteneciente al Area Programática III con cabecera en la Ciudad de Perico, que abarca las localidades de Puerto Viejo, Pampita, El Milagro, Aguas Calientes, Manantiales y Pampa Blanca. Se realizaron 73 encuestas y de las mismas al analizar los principales factores de riesgo surge : - Alta frecuencia de Ingesta de agua de acequia sin potabilizar (37,1 por ciento ), que está en relación a la falta de agua potable en el hogar (22,2 por ciento ) y en el lugar de trabajo (32,2 por ciento ). - Ingesta de frutas (47,9 por ciento ) y de verduras crudas (22,9 por ciento ) productos estos que pueden estar contaminados por el V. cholerae de acuerdo a su manipulación y riesgo. Del análisis estadístico de estos factores de riesgo surge como causa más significativa el consumo de agua de acequia sin potabilizar (O.R.=7,2:X=11,6:P<0,001). Analizando el riesgo atribuible poblacional para agua de acequia sin potabilizar nos indica que eliminando este factor, se podría disminuir la posibilidad de enfermar de cólera en un 70 por ciento aproximadamente, en el área estudiada. Esto reafirma que trabajando sobre los tres pilares fundamentales para el control y erradicación del cólera : calidad de agua, saneamineto del medio y educación para la salud, es posible el control de esta enfermedad
