We observed that the repertoire of proteins reactive with sera from individuals recovering from natural Types A and B infection showed a great deal of overlap, as shown in Fig. 3a and d. This is interesting, given that the most common route of infection for Type A Francisella in the Martha's Vineyard patients is inhalational ( Matyas et al., 2007), whereas the most common route of infection in the European type B infected group is presumed to be arthropod-borne intradermal ( Sjostedt, 2007).