MODERN LABORATORY DIAGNOSTIC METHODS IN VETERINARY MEDICINE AND THE POSSIBILITY OF ITS APPLICATION

One of the greatest challenges of modern laboratory diagnosis is the selection of methods for fast, highly sensitive and specific detection of the infective agents. This challenge is present also in molecular diagnosing of causative agents in veterinary medicine. An example of molecular detection, the application of molecular diagnostic methods and procedures in the epizootiology of some viral infections is presented in the paper. The molecular methods play an important role in virus detection and surveillance. Out of a large number of molecular methods most frequently used are classical gel-based PCR (PCR, RT-PCR and nested PCR) and real-time PCR or RT-PCR techniques. Due to highly specificity and sensitivity these methods have been introduced as internationally recognized methods for virus detection in clinical materials. The advantage of the aforementioned molecular methods is that they are very fast and highly sensitive, and able to analyse a high number of samples. The obtained results may be used in molecular epizootiology, possibly for differentiation of filed isolates and vaccine virus strains, and for examining the samples not suitable for virus isolation. Alongside, these methods provide accurate quantification of viral particles in sample material. The detection with high sensitivity and specificity is of utmost importance in detection and typisation of the agents of highly contagious diseases and zoonoses. An example of rapid detection and sensitivity of RT-PCR and real-time RT-PCR in detection and characterization of avian influenza virus in clinical material as well as BVD virus in native bull semen is presented. Besides, molecular methods may be used for other purposes. Genome fragments amplified by PCR and RT-PCR, may be sequenced and used for classification, i.e. for virus isolate genotypisation. The results obtained in this way may be used for basic molecular research in epizootiology, that will point on the source of infections, their correlation and the prevalence of the causative agents what can help in finding the answer to the question why the diseases have occurred and what are the perspective for diseases outcome in the future. Also, these examination may help in determining pathogenicity, virulence and the spread of the pathogen agents. These information are of immeasurable importance for all the procedures in disease prevention and control. The possibilities of sequencing, molecular typisation and epizootiology of BVD virus and CSF virus isolated in Vojvodina in the last years are given as an example how this method can be used.