Diagnostic preparedness in Europe for detection of avian influenza A(H7N9) viruses

Technical guidance Guide

In China, a novel avian-origin reassortant influenza A(H7N9) virus has been detected in a number of human cases. In response to the potential cross-border health threat associated with emerging disease caused by the appearance of the novel virus, European laboratories need to be aware of the novel virus and adapt and confirm their diagnostic capability to detect and identify it. This document is a joint CNRL/ECDC/WHO Europe technical briefing note for virology laboratories. It is designed to assist clinical and public health laboratory directors in appraising options for establishing novel diagnostic assays for screening and confirming cases of infection in humans. This document is intended for use in the area of human influenza surveillance, investigation, risk assessment, and control, encouraging cooperation between expert and reference laboratories in order to foster the development of sufficient capacity within the Community for the diagnosis, detection, identification and characterisation of infectious agents which may threaten public health. This document contains a list of laboratory preparedness considerations to ensure European-wide diagnostic capability; an update on current methods used for molecular detection of human infection with avian influenza A(H7N9) virus by RT-PCR;a table of H7 HA assay validation criteria; information on positive controls for RT-PCR assays.

Executive summary

A novel avian-origin reassortant influenza A(H7N9) virus has been detected in a number of human cases in China since March 2013. To assist European laboratories in verifying and ensuring their diagnostic capability to detect and identify this virus, ECDC jointly with CNRL and WHO Europe is releasing a technical briefing note on Diagnostic preparedness in Europe for detection of avian influenza A(H7N9) viruses. 

The briefing note provides:

  • a list of laboratory preparedness considerations to ensure European-wide diagnostic capability;
  • an update on current methods used for molecular detection of human infection with avian influenza A(H7N9) virus by RT-PCR;
  • a table of H7 HA assay validation criteria;
  • information on positive controls for RT-PCR assays.

Specifically on H7 detection capabilities, the document includes the following considerations:

  • Laboratories testing for H7 will require a molecular detection capability allowing same-day specific detection ability in response to clinical queries or case scenarios.
  • A two-step approach for detection and confirmation of avian influenza A(H7N9) virus infection should be followed.
  • Laboratories require: (i) a generic influenza A virus testing capability which will assuredly detect an avian influenza A(H7N9) virus within the Eurasian lineage as influenza A and (ii) a specific H7 HA detection capability to confirm the presence of an avian influenza A(H7N9) virus in a sample which is positive for influenza A, but negative for H1, H3 and H5.

Further assessment and monitoring of avian influenza A(H7N9) virus detection capability in laboratories is on-going to ensure diagnostic coverage in Europe.

ECDC provides regular updates on avian influenza A(H7N9) virus, and continues to closely monitor and re-assess the situation in collaboration with WHO, US CDC, China CDC and other partners.