Immunohistochemistry. Sections were pretreated with Dako Ready to Use Proteinase K (Dako, http://www.dako.com) for 6 min at RT after deparaffinization and rehydration through a series of graded ethanols. Blocking was performed with Dako's Serum-Free Protein Block for 20 min pre-antibody exposure. The tissue sections were then incubated overnight at 4 8C in primary antibody using an equal mixture of mouse monoclonal antibodies to EBOV GP and VP40 (1:5,000). An alkaline phosphatase-labeled polymer (Dako Envision System, alkaline phosphatase) was incubated on the sections for 30 min, and then color was developed by exposing tissue to 6-bromo-2hydroxyl-3-naphtholic acid (HistoMark Red; Kikegaard and Perry Laboratories, http://www.kpl.com) substrate for 50 min in the dark. Counterstaining was done with hematoxylin. Positive controls included archived EBOV-infected cynomolgus tissue, and negative controls included replicate sections exposed to anti-Marburg virus antibodies and uninfected cynomolgus macaque tissue [15] . Public health preparedness in Alberta: a systems-level study BACKGROUND: Recent international and national events have brought critical attention to the Canadian public health system and how prepared the system is to respond to various types of contemporary public health threats. This article describes the study design and methods being used to conduct a systems-level analysis of public health preparedness in the province of Alberta, Canada. The project is being funded under the Health Research Fund, Alberta Heritage Foundation for Medical Research. METHODS/DESIGN: We use an embedded, multiple-case study design, integrating qualitative and quantitative methods to measure empirically the degree of inter-organizational coordination existing among public health agencies in Alberta, Canada. We situate our measures of inter-organizational network ties within a systems-level framework to assess the relative influence of inter-organizational ties, individual organizational attributes, and institutional environmental features on public health preparedness. The relative contribution of each component is examined for two potential public health threats: pandemic influenza and West Nile virus. DISCUSSION: The organizational dimensions of public health preparedness depend on a complex mix of individual organizational characteristics, inter-agency relationships, and institutional environmental factors. Our study is designed to discriminate among these different system components and assess the independent influence of each on the other, as well as the overall level of public health preparedness in Alberta. While all agree that competent organizations and functioning networks are important components of public health preparedness, this study is one of the first to use formal network analysis to study the role of inter-agency networks in the development of prepared public health systems. International and national events have brought critical attention to the Canadian public health system and how prepared the system is to respond to various types of con-temporary public health threats. Whether those threats result from emerging infectious diseases or bioterrorism, the public health system is responsible for protecting the health of the population. Outbreak response occurs first at the local or regional levels and thus the potential impact that a threat will have on the overall Canadian population can differ significantly depending on the capacity of public health systems to respond [1] . For example, following the SARS outbreak in Toronto, the Canadian National Advisory Committee (NAC) on SARS and Public Health held it as fortunate that the SARS outbreak struck primarily in Toronto and not in other parts of Canada where the capacity to combat public health threats is limited [2] . While a "general renewal of the public health infrastructure" and its capacity to respond are in order the effective coordination of all agencies at regional, provincial, and federal levels is necessary to assure a comprehensive surveillance and management of public health threats. As Ralph Klein, the Premier of Alberta, commented: "Albertans and all Canadians understand a disease outbreak like SARS or West Nile virus in one region affects other parts of the country. Coordinated approaches will help deal with public health threats."