We tested sera from four different groups of animals defined on infection status (Table 1, group 6, 7, 8, 9): MAP positive animals and MB negative (MAP + MB −), n = 254; MAP positive and MB positive animals (MAP + MB +), n = 147; MAP negative and MB positive (MAP − MB +), n = 69 animals; and MAP negative animals and MB negative animals (MAP - MB -), n = 30 animals. The gene discussed is MB; the disease is infection.