ADA and bacterial infectious disease: Although these findings should be tested with a larger number of animals, in a farm positive to PRRSV, the presence of increases in Hp and LDH in saliva could indicate the possibility of the activation of the disease, whereas additional increases in Serpin B12, aldolase, calprotectin, total protein, and/or ADA in saliva could indicate the presence of a bacterial disease that should be diagnosed and treated.