Long-term observation of canine brucellosis: excretion of Brucella canis into urine of infected male dogs.

Six male dogs orally inoculated with 3.2 X 10(8) Brucella canis and 2 male dogs naturally infected with the organisms were examined weekly for the presence of the organisms in urine and blood as well as for agglutinin titers in serum. Excretion of the organisms into urine started on 1 to 3 weeks after onset of bacteremia, i.e. 4 to 8 weeks after inoculation, and lasted for about 1 to 1.5 years. Non-bacteremic intervals, intermittent or lasting for about 1 to 6 months, followed the initial period of abundant excretion of viable organisms in urine. The highest urinary concentrations of the organisms, 2.5 X 10(4) to 1.5 X 10(6) cells per ml, were obtained in all dogs between the 6th and 14th weeks after the oral inoculation. Serum agglutinin titer rose on the 3rd to 5th weeks after the inoculation and then the titers remained at 1 : 640-1 : 2,560. The titers showed a downward trend over the 40 th to 56th weeks after the inoculation. In one of the spontaneously infected cases, the organisms were demonstrable only from urine for half a year with suspicious serum agglutinin titer of 1 : 160 after the bacteremic phase.