Because of the low specificity within uninfected samples, we have also investigated cross-reactions with other ehrlichiosis (Anaplasma phagocytophilum, Ehrlichia canis, Ehrlichia ewingii and Ehrlichia sennetsu) and other bovine diseases (brucellosis, leptospirosis, salmonellosis and babesiosis), and only the Am2 peptide cross-reacted with sera of animals with brucellosis. This evidence concerns the gene ADM2 and cattle disease.