[Serological studies in bovine Q fever].

A serologic study was carried out by means of the complement-fixation test (CFT) and the immunofluorescence titration method (ITM) of a total of 1250 blood samples from 13 farms, having records of abortions, retention of placentae, and endometritis. The comparison of CFT and ITM results showed that 44 (52.3 per cent) of the positive sera were altogether positive by the two methods, 24 (28.6 per cent) sera yielded positive reactions by CFT and negative ones by ITM, and 16 (19 per cent) sera proved positive by ITM and negative by CFT. In two cows that were experimentally infected with rickettsiae the complement-fixing antibodies appeared between the 8 h and 15th day, and persisted up to the 160th day, their titers reaching peak values of up to 1:160. Recorded was the dynamics of the complement-fixing antibodies in spontaneously infected cows that miscarried. In this case too the titers were not high--1:10 to 1:40. They persisted in the course of six months.