Autor(es):
Guiomar, Raquel 
; Pechirra, Pedro ; Conde, Patrícia ; Cristóvão, Paula ; Silvestre, Maria José ; Almeida Santos, Madalena ; Sobrinho Simões, Joana ; Costa, Maria do Rosário ; Amaral, Susana ; Guimarães, João Tiago ; Ribeiro, Graça ; Correia, Lurdes ; Fernandes, Aida ; Milho, Luís ; Fernandes, Paula Luísa ; Andrade, Graça ; Mota Vieira, Luísa ; Cabral, Rita ; Moniz, Raquel ; Pereirinha, Tania ; Bruges Armas, Jacome ; Pimentel Couto, Ana Rita ; Soares, Marta ; Melo Cristino, José ; Carvalho, Dinah ; Ribeiro, Carlos ; Barreto, Rosário ; Côrte-Real, Rita ; Branquinho, Paula ; Ramos, Maria Helena ; Castro, Ana Paula ; Caldeira, Filomena ; Maurílio, Manuel ; Cunha, Mário ; Ornelas, Carmo ; Almeida, Sofia
Data: 2013
Identificador Persistente: http://hdl.handle.net/10400.18/1727
Origem: Repositório Científico do Instituto Nacional de Saúde
Assunto(s): Infecções Respiratórias; Gripe; Portuguese Laboratory Network for Influenza; Severe Acute Respiratory Infections
Descrição
During the 2009/10 influenza pandemic, a network of 14 laboratories located in the main reference hospitals from Portugal mainland, Madeira and Azores was established for the diagnosis of the new influenza A(H1N1)2009 pandemic strain. Since then, the network performs laboratory diagnosis of influenza as well as other respiratory pathogens, thus contributing to the laboratory diagnosis of respiratory disease in Portugal. This network is a valuable complement of the National Influenza Surveillance Programme (mainly based on primary healthcare units), enabling a more accurate knowledge of the aetiology of the severe respiratory infections, especially in hospitalized cases. The present study describes the severe acute respiratory infections, in the 2012/2013 season, diagnosed by the laboratory network.
From the 14 laboratories, 11 reported cases of respiratory disease during 2012/2013 season. The laboratory network performs diagnosis of influenza A and B viruses and other respiratory agents by PCR based methods, also enabling the detection of mixed infections. All 14 laboratories perform the detection of influenza A(H1)pdm09, 4 perform the influenza A(H1) seasonal and A(H3) subtyping, and 10 participants also detect influenza B. Eight laboratories implemented methodologies for the detection of other infectious agents associated with respiratory disease. The antigenic characterization of 8 isolated viruses [3 A(H1)pdm09 and 5 B/Yamagata] was performed at the National Influenza Reference Laboratory. The genetic analysis of the HA1 subunit of the haemagglutinin gene was performed in 17 viruses [7 A(H1)pdm09, 1 A(H3) and 9 B/Yamagata]. Twenty nine A(H1)pdm09 and 5 B/Yamagata were tested for antiviral susceptibility [PCR(NA)-H275Y and/or MUNANA phenotypic assays for oseltamivir and zanamivir].
The 11 laboratories reported a total of 1470 respiratory disease cases, from week 39/2012 to 21/2013 [peak of 205 (13.9%) cases during week 10/2013]. Influenza was identified in 504 cases. Influenza A was detected in 352 (70.0%) cases: 297 (59.0%) cases were A(H1)pdm09, 48 (10.0%) cases were not subtyped, and 7 (1.0%) cases were A(H3). Influenza B was identified in 152 (30%) of the influenza cases.
During the 2012/2013 season, 311 (21.2%) reported cases were hospitalized in intensive care units (ICU), the majority of them had between 50-54 years (34; 10.9%), followed by the age groups 45-49 and 55-59 years old (28; 9.0% each). The causal agent was identified in 160 (51.4%) ICU cases. Influenza was identified in 120 (38.5%) patients, other respiratory agents were detected in 40 (12.8%), within these, multiple infections were present in 18 (5.7%). Bacteria were identified in 31 (10.0%) cases mainly associated with RSV and hRV.
Among ICU influenza cases, the most detected virus was A(H1)pdm09 (82; 62.0%). However, cases of A(H3) (3; 2.0%), A unsubtyped (8; 7.0%) and B (27; 23.0%) were also detected. As expected, the highest number of ICU influenza positive cases was detected in week 10/2013 (18; 15.0%), coincident with the highest number of influenza cases during all season. ICU flu cases were detected predominantly in individuals between 50-54 years (18; 15.0%). From the ICU reported cases, 6 (1.9%) died. The influenza A(H1)pdm09 virus was detected in 2 man between 50-59 years old from these 6 fatal outcomes.
The isolated influenza A viruses were similar to the 2012/2013 vaccine strains. The influenza B/Yamagata viruses showed a greater antigenic and genetic variability.
The Portuguese Laboratory Network for Influenza Diagnosis plays a major role in the diagnosis of acute respiratory infections in Portugal, providing a more accurate knowledge of the respiratory agents involved.
During the 2012/2013 season, the influenza A(H1)pdm09 virus predominated in co-circulation with influenza B virus. The A(H1)pdm09 virus was the responsible for the majority of the flu cases admitted in the ICU and may have been the cause of death in two cases. Bacterial and other viral agents have been identified in some of the severe cases reported. The majority of the characterized influenza viruses were similar to the vaccine strains and none of the virus showed reduced susceptibility to oseltamivir or zanamivir.
