cough; and seasonal influenza. NML also has Containment Level 3 (CL3) laboratories (8.6% of lab space). Risk Group 3 pathogens may be transmitted by the airborne route, often need only a low infectious dose to produce effects, and can cause serious or life-threatening disease. CL3 emphasizes additional primary and secondary barriers to minimize the release of infectious organisms into the immediate laboratory and the environment. Additional features to prevent transmission of CL3 organisms are appropriate respiratory protection, HEPA filtration of exhausted laboratory air, and strictly controlled laboratory access. Examples include tuberculosis; West Nile virus; and pandemic H1N1 influenza. A small percentage of laboratory space (3.6%) is devoted to Containment Level 4 (CL4) at NML. These agents have the potential for aerosol transmission, often have a low infectious dose and produce very serious and often fatal disease; there is no licensed treatment or vaccine available. This level of containment represents an isolated unit independent of other areas. CL4 emphasizes maximum containment of the infectious agent by completely sealing the facility perimeter with confirmation by negative pressure testing, isolation of the researcher from the pathogen by an enclosed positive pressure suit, and decontamination of air and all other materials. Examples include Ebola, Nipah, Marburg, and 1918 pandemic influenza. Structure NML programs are housed in several facilities across the country. Two of these facilities are in proximity to each other in Winnipeg: The Canadian Science Centre for Human and Animal Health on Arlington Street and the J.C. Wilt Infectious Diseases Research Centre on Logan Avenue. The other facilities are located in Guelph, ON; St. Hyacinthe, QC and Lethbridge, AB. NML is divided into five main laboratory divisions which are supported by scientific and administrative services. The primary NML divisions are: Bacterial Pathogens - focussing on bacterial diseases such as tuberculosis and antibiotic resistant organisms. Enteric Diseases - focussing on food and water-borne pathogens including E.coli and Salmonella. Viral Diseases - addressing a range of viral diseases, including hepatitis and other blood-borne pathogens, respiratory viruses and viral exanthemata, such as measles. Zoonotic Diseases and Special Pathogens - dealing with viral, bacterial and rickettsial zoonoses (diseases transmitted to humans from other species), such as West Nile Virus and Lyme disease, along with risk group 4 agents such as Ebola, Marburg and Lassa fever viruses. HIV and Retrovirology - providing laboratory services and scientific expertise relating to HIV and emerging retroviruses. The Science Technology Core and