# 6114
With the recent flap over the creation of two highly transmissible laboratory strains of the H5N1 virus, there have been calls to restrict this kind of research to labs with only the highest levels of biosecurity.
In the United States, this level of containment is called Biosecurity Level 4 (BSL-4) or sometimes BL-4, but in other parts of the world similar high containment labs go by different names.
In Australia, they are designated "PC4,'' which stands for "physical containment 4”, while in Canada, these labs are called Containment Level 4 (CL-4).
While most of these facilities boast truly impressive biosecurity precautions, there are no universally mandated standards, and so practices and techniques may vary from one country to the next.
Today, the Public Health Agency of Canada has issued a Biosafety Advisory for working with transmissible strains of the H5N1 virus, relegating such work to their highest containment (CL-4) labs.
Biosafety Advisory: Efficiently Transmissible Engineered Influenza A H5N1 Viruses
February 01, 2012
This biosafety advisory is being provided by the Public Health Agency of Canada (PHAC) in response to recent publications of efficiently transmissible engineered Influenza A H5N1 viruses. The Pathogen Regulation Directorate (PRD) has developed this advisory based on current scientific evidence available on this pathogen and is subject to review and change as more information becomes available. The Risk Group (RG) of efficiently transmissible Influenza A H5N1 viruses is RG4.
1. Background
Influenza A H5N1 is a highly pathogenic avian influenza virus that emerged as a human pathogen in 1997 when it was transmitted from avian populations to humans in Hong Kong(1,2). Since then, various countries around the world have reported human infections, particularly in Southeast Asia, the Middle East, and Africa. From 2003 to 2011, 574 human cases and 337 deaths have been confirmed by the World Health Organization; this correlates to a mortality rate of 59%(3). H5N1 can cause death in healthy individuals with no pre-existing medical conditions.
In November 2011, three independent studies on H5N1 transmission in ferrets were either published online or submitted for publication. These studies have received a significant amount of attention due to their relative success in producing engineered H5N1 viruses capable of efficient transmission in ferrets, including via the air(4-10). Ferrets are considered a good model for studying human influenza viruses(11). The engineered transmissible H5N1 viruses are not currently in circulation, but it is widely agreed that if released, the clinical and economic impact could be devastating.
2. Biosafety Requirements
The following table summarizes the containment requirements for laboratories working with efficiently transmissible engineered Influenza A H5N1 viruses. No containment requirements are stipulated for non-proliferative clinical/diagnostic activities based on the fact that this virus is currently not in circulation. Laboratories should refer to the Laboratory Biosafety Guidelines, 3rd Edition, 2004 for a complete listing of the biosafety requirements.
H5N1 viruses capable of efficient human-to-human transmission, including via aerosols or the airborne route, are considered Risk Group 4 human pathogens and require Containment Level 4 physical containment and operational practices.
3. Additional Risk Considerations
If an efficiently transmissible H5N1 virus was introduced into circulation, a risk assessment would be necessary to determine the regulatory requirements for different types of work, such as non-proliferative clinical/ diagnostic activities.
