Virological surveillance of the influenza A(H1N1)2009 pandemic: the role of the belgian national influenza centre

According to the WHO [7, 8], the responsibilities of the NIC during the pandemic period are: 1) to provide laboratory diagnosis for monitoring the geographical spread of the pandemic in the country; 2) as the pandemic intensifies and becomes widespread, to adjust virological surveillance in order to monitor the progress of the pandemic in the country; 3) to maintain adequate virological surveillance to assist WHO in monitoring for example antigenic and genetic changes in the pandemic virus, pathogenicity, and antiviral susceptibility. [...]during this phase, the NIC strengthened the nationwide surveillance system to study the A(H1N1)2009 virus circulation in the Belgian population and to help reduce influenza morbidity and mortality. [...]the influenza virological sentinel surveillance network, previously composed of 98 general practitioners (GPs) distributed in the whole country [11], was expanded to 139 GPs (78 GPs located in Flanders, 49 in Wallonia and 12 in the Brussels-Capital Region) (Figure 1). SEE PDF] Laboratory testing At the start of the pandemic, there was still a lack of information about the pathogenicity and transmission of the virus. [...]to avoid any possible reassortment between strains from swine and human origins, manipulation and RNA extraction of the suspect specimens were performed in biosafety level 3 (BSL3) facilities instead of BSL2 where similar samples are tested yearly within the framework of monitoring seasonal flu. At first, there was no specific test available for the new pandemic influenza virus. [...]the suspect samples were tested for influenza A and B, and subtyped for seasonal influenza A/H1 and A/H3.