Estimation of the Serial Interval for Pandemic Influenza (pH1N1) in the Most Southern Province of Argentina.

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.

Protection of trivalent inactivated influenza vaccine against hospitalizations among pandemic influenza A (H1N1) cases in Argentina.

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.

[Exanthematous outbreak caused by human parvovirus B19 in a school in Banderaló, Argentina]. / Brote exantemático por parvovirus humano B19 en una escuela de Banderaló, Argentina.

We report an exanthematic outbreak in a school of Banderaló town, located in the district of General Villegas, Buenos Aires province, Argentina. This outbreak affected 21 individuals, with a wide range of age (out of a total population of 1400). The observed clinical manifestations were exanthema and in some cases fever, asthenia, arthropathies and myalgia. The presence of specific IgM antibodies against measles, rubella and human parvovirus B19 were investigated. Analysis of IgM antibodies to parvovirus B19 by ELISA was positive in 90.8% of the cases and viremia was detected in 66.7% of the patients by nested PCR. These results indicate that human parvovirus B19 was the etiologic agent of the outbreak and they confirm its circulation in Argentina. Moreover, this study demonstrates that PCR may be useful for the study of transmission foci and of individuals with prolongued clinical manifestations. We consider that it is necessary to include the differential diagnosis of human parvovirus B19 in the surveillance of exanthematic virosis.

Brote exantemático por parvovirus humano B19 en una escuela de Banderaló, Argentina. / [Exanthematous outbreak caused by human parvovirus B19 in a school in Banderaló, Argentina]

We report an exanthematic outbreak in a school of Banderaló town, located in the district of General Villegas, Buenos Aires province, Argentina. This outbreak affected 21 individuals, with a wide range of age (out of a total population of 1400). The observed clinical manifestations were exanthema and in some cases fever, asthenia, arthropathies and myalgia. The presence of specific IgM antibodies against measles, rubella and human parvovirus B19 were investigated. Analysis of IgM antibodies to parvovirus B19 by ELISA was positive in 90.8

of the cases and viremia was detected in 66.7

of the patients by nested PCR. These results indicate that human parvovirus B19 was the etiologic agent of the outbreak and they confirm its circulation in Argentina. Moreover, this study demonstrates that PCR may be useful for the study of transmission foci and of individuals with prolongued clinical manifestations. We consider that it is necessary to include the differential diagnosis of human parvovirus B19 in the surveillance of exanthematic virosis.

Brote exantemático por parvovirus humano B19 en una escuela de Banderaló, Argentina / [Exanthematous outbreak caused by human parvovirus B19 in a school in Banderaló, Argentina]

We report an exanthematic outbreak in a school of Banderaló town, located in the district of General Villegas, Buenos Aires province, Argentina. This outbreak affected 21 individuals, with a wide range of age (out of a total population of 1400). The observed clinical manifestations were exanthema and in some cases fever, asthenia, arthropathies and myalgia. The presence of specific IgM antibodies against measles, rubella and human parvovirus B19 were investigated. Analysis of IgM antibodies to parvovirus B19 by ELISA was positive in 90.8

of the cases and viremia was detected in 66.7

of the patients by nested PCR. These results indicate that human parvovirus B19 was the etiologic agent of the outbreak and they confirm its circulation in Argentina. Moreover, this study demonstrates that PCR may be useful for the study of transmission foci and of individuals with prolongued clinical manifestations. We consider that it is necessary to include the differential diagnosis of human parvovirus B19 in the surveillance of exanthematic virosis.