On the basis of restriction enzyme cleavage profiles, they can separated into two serologically cross-reacting types, CAd1 and CAd2. CAd1 is the more invasive of the two, and predominates in wildlife.
Vaccine strains of both types exist.
The genomic organization of each is for the most part very similar to that of the human adenoviruses. Major differences include the absence of any VA-RNA coding region, and a much smaller E3 region in both CAd1 and CAd2. This results in non-production of a 23K glycoprotein which appears to be analogous to the gp19K of human Ads 2 and 5. This may provide the molecular basis for its vaccine characteristics. Yarosh, DK, Wandeler, A, Graham, FL, Campbell, JB and Prevec, L. Human adenovirus type 5 vectors expressing rabies glycoprotein.