Establishment of a UK National Influenza H5 Laboratory Network

Avian (H5N1) influenza continues to pose a significant threat to human health, although it remains a zoonotic infection. Sensitive and robust surveillance measures are required to detect any evidence that the virus has acquired the ability to transmit between humans and emerge as the next pandemic strain. An integral part of the pandemic planning response in the UK was the creation in 2005 of the UK National H5 Laboratory Network, capable of rapidly and accurately identifying potential human H5N1 infections in all regions of the UK, and the Republic of Ireland. This review details the challenges that designing molecular detection methods for a rapidly evolving virus present, and the strategic decisions and choices required to ensure successful establishment of a functional national laboratory network, providing round the clock testing for H5N1. Laboratory partnerships have delivered improved real-time one-step multiplex PCR methodologies to ensure streamlined testing capable of not only detecting H5 but also a differential diagnosis of seasonal influenza A/B. A range of fully validated real-time PCR H5 confirmatory assays have been developed to run in parallel with a universal first-screening assay. Regular proficiency panels together with weekly surveillance runs, intermittent on-call testing for suspect cases of avian flu in returning travellers, and several outbreaks of avian influenza outbreaks in poultry that have occurred since 2005 in the UK have fully tested the network and the current diagnostic strategies for avian influenza. The network has clearly demonstrated its capability of delivering a confirmed H5N1 diagnosis within 3-4 h of receipt of a sample, an essential prerequisite for administration of the appropriate antiviral therapy, effective clinical management, disease containment and implementation of infection control measures. A functional network is an important means of enhancing laboratory capability and building diagnostic capacity for a newly emerging pandemic of influenza, and is an essential part of pandemic preparedness.