Serological monitoring and risk factors of brucellosis and Q fever in calves in Türkiye

The death and loss of offspring before the gestation period is complete is defined as abortion. All calf losses before the 200th day of pregnancy are defined in this way. Brucellosis and Q fever diseases are among the most important abortive diseases in cattle. This study examined the seropositivity rates of brucellosis and Q fever in 3- to 6-month-old calves not vaccinated with Brucella abortus S19. Six hundred and 81 calves were included, and blood serum samples were collected. The rose Bengal plate test (RBPT), indirect enzyme-linked immunosorbent assay (ELISA), and complement fixation test (CFT) tests were used to diagnose brucellosis, and indirect ELISA was used to diagnose Q fever. Among the calves whose blood serum was collected, the positive results for the RBPT, indirect ELISA, and CFT tests were 3.5%, 8.8%, and 5.5%, respectively. A positivity rate of 6.6% was determined for Q fever. In the study, the co-infection rate of brucellosis and Q fever was determined to be 0.44%. On the other hand, the seropositivity of brucellosis and Q fever in calves was not significant (p > 0.05) according to sex and age. The calves born in the study area were infected either intrauterine or during the postpartum period. In addition, ELISA had higher sensitivity than the other tests. Therefore, the combination of RBPT and indirect ELISA should be used in herd screenings to detect more infected animals.