The early days of pandemic (H1N1) 2009 virus infection in the central region of Portugal

Abstract

Background: The first case of pandemic (H1N1) 2009 virus infection was diagnosed in the central region of Portugal on June 16, 2009, in a woman infected in Canada. Methods: The aim of our study was, first to characterize the clinical and epidemiologic aspects of all the patients with clinical manifestations included in the definition of a case for investigation with samples submitted to diagnosis of the pandemic (H1N1) 2009 virus infection, in the central region of Portugal; second, to assess the precision of the case definition of case for investigation considered in the study according to the presence or the absence of fever at the moment of clinical observation. We reviewed the medical records of all the patients presenting with Influenza like-illness classified as a case for investigation and the first cases of patients infected with the new pandemic (H1N1) 2009 virus, diagnosed in the central region of Portugal during the pandemic period between June and August, 2009, were analyzed. Real-time reverse-transcriptase polymerase-chain-reaction (RT-PCR) testing was used to confirm the pandemic (H1N1) 2009 virus infection. Data collection was performed using a standardized paper format in agreement with the General Health Directorate. Results and discussion: Pandemic (H1N1) 2009 virus infection was confirmed in 255 patients. Overall, median age was 23 years and 42.7 % were included in the category of 20 to 29 years. Confirmed infection in patients with less than 2 years or greater than 50 years was a rare event. The first cases were imported from Europe, namely France, Spain and England. In a second phase, pandemic (H1N1) 2009 virus infection was acquired in the south of Portugal (Algarve). The incidence rate for pandemic (H1N1) 2009 virus infection was 10.7 per 100,000 persons and was different according to the district. It was higher in the district of Coimbra and Guarda where the main roads are connecting to Europe. The median calculated incubation period for the for pandemic (H1N1) 2009 virus infection was 2 days. The length of the clinical manifestations until the patients sough for medical observation had a median time of 2 days. All the cases were of mild to moderate severity. No deaths were observed. Conclusions: The early days of pandemic (H1N1) 2009 virus infection were characterized by cases of disease of mild to moderate severity, in our region. Most affected patients were young adults, with the extreme ages of life being spared. An early diagnosis, strict isolation and treatment procedures could have slowed the spread of the infection. © 2010 Published by Elsevier España, S.L. on behalf of Sociedade Portuguesa de Pneumologia. All rights reserved.