[Allergic diagnosis of bovine brucellosis. 2. Use of the allergic test in infected herds (author's transl)].

Four hundred and eighty-one cows, in 27 herds, were injected intradermally with a brucella purified protein allergen in order to study the value of the skin test in the diagnosis of bovine brucellosis. The serology was done on the serum or plasma from 444 of these cows. Two hundred and nine cows showed an allergic reaction and 174 were positive in serology. One hundred and twenty-three were simultaneously positive to both tests, 52 were positive in serology but did not show any allergic reaction and 66 showed an allergic reaction but were negative in serology. In general, brucellosis was certainly detected at the herd level with this test. In newly-infected herds, the skin test gives a more complete and earlier result than serological tests. The use of the skin test is recommended as a supplemental test when unknown animals are to be introduced in non-infected herds, to improve the detection of contaminated animals in newly-infected herds and to solve the case of problem herds.