THE PREVALENCE OF TEN PATHOGENS DETECTED BY A REAL-TIME PCR METHOD IN NASAL SWAB SAMPLES COLLECTED FROM LIVE CATTLE WITH RESPIRATORY DISEASE

Respiratory diseases often correspond to primary infections with different pathogens of cattle, causing heavy economic losses in young stock and breeding herds. Between 2012 and 2014, nasal swab samples were collected from twenty-eight herds from 133 affected live cattle that were clinically suffering from symptoms of respiratory disease, pyrexia, cough, serous nasal and lacrimal discharge, increased respiratory rate, and breath sounds. Individual swab samples were tested in the laboratory using three commercial and one in-house real-time PCR methods, to detect nucleic acids of a total of ten different respiratory pathogens. Pasteurella multocida (P. multocida) was detected in 58.65% of samples, Mannheimia haemolytica (M. haemolytica) in 15.04%, while Mycoplasma bovis (M. bovis) and Histophilus somni (H. somni) were positive in 9.77% of nasal swab samples. Among viral pathogens, the highest prevalence (40.60%) was observed for bovine respiratory syncytial virus (BRSV), followed by bovine coronavirus (BCV) 12.03%, bovine para-influenza 3 (PI-3) 3.01%, and bovine viral diarrhea virus (BVDV) with 1.50% of positive samples. The less frequently detected viral pathogens were bovine herpes virus type 1 (BHV-1) and bovine adenovirus (BAdV) with 0.75% positive samples each. The new implemented molecular methods can be an important diagnostic tool for laboratories and farmers to improve the therapy, control, and prevention of respiratory disease in cattle herds.