The present invention is directed to diagnostic tools and therapies using antibodies to Bacillus anthracis. Specifically, the present invention is directed to a B. anthracis-specific monoclonal antibody that binds to the EA1 antigen (corresponding to the eag gene) of the S-layer (surface layer) of spores. This monoclonal antibody may be used in a variety of applications, including to specifically detect and diagnose B. anthracis. Preferably, antibodies are monoclonal and bind to a surface protein, such as EA1 protein, on the spores of B. anthracis, and not to spores of either B. cereus or B. thuringiensis. Antibodies can be incorporated into detection kits using, for example, colloidal particle based lateral flow detection system. Such detection kits can distinguish anthrax spores from non-pathogenic varieties of spores. In addition, the invention is directed to B. anthracis EA1 antigen and pharmaceuticals such as vaccines that can be used as therapeutics and to develop improved antibodies and detection methods.