Comparative investigation of bacteriological and serological methods and polymerase chain reaction in the diagnostics of leptospirosis in cattle. [Doctoral dissertation] | Упоредно испитивање бактериолошких и серолошких метода и полимераза ланчане реакције у дијагностици лептоспирозе говеда. Докторска дисертација

Leptospirosis is worldwide considered important animal and human infectious disease from a health and economic point of view. Detection of infected animals, above all the carrier animals, is an intricate process with respect to validity of applied serological tests, as well as complex and time-consuming isolation procedure. Experimental research was conducted on rabbits experimentally infected with L. hardjo in four manners: via skin scarification, subcutaneous administration, intravenous administration and intraocular application of live cultures of the serovar L. hardjo. Presence of leptospirosis in cattle was investigated in the samples of blood, blood serum and urine of naturally infected cows. Detection of specific antibodies against L. hardjo in rabbits and cows was performed employing MA test, commercial ELISA and modified ELISA assays. Presence of L. hardjo in experimentally infected rabbits and naturally infected cows was confirmed using culture methods in liquid and semisolid medium, whilst presence of leptospiral genome was established using polymerase chain reaction (PCR) test. Presence of specific antibodies against L. hardjo by the use of MA test was confirmed in 59.01% out of 744 experimentally infected rabbits. ELISA method revealed positive results in 41.4% rabbit blood sera, and suspect findings were observed in 86 (11.11%) samples. Leptospira hardjo was recovered from 120 (16.12%) out of 744 examined blood sera of experimentally infected rabbits. Using a PCR method presence of L. hardjo genome was confirmed in 232 (48.73%) samples of rabbit blood sera. MA method was utilized to investigate 116 blood serum samples of cows. Bacteriological examination of urine by the method of isolation of L. hardjo revealed 10 (45.45%) positive findings. According to the obtained results we can conclude that application of PCR method will emerge in the diagnostics of leptospirosis, enabling timely detection of infected animals and application of control programs.