Veterinary Research Forum

Abstract Bovine respiratory disease (BRD) is a significant disease in the cattle industry worldwide. The interaction between environmental factors, hosts, livestock management, and viral and bacterial pathogens causes this disease. Viruses are crucial in the initiation and progression of BRD. This study was the first to investigate the prevalence of BRD viruses using the reverse transcription polymerase chain reaction method in nasal and eye conjunctival swabs and blood samples of 115 BRD calves in the central desert of Iran. At least one investigated virus was detected in 44 animals (38.26%). The detection rates of bovine viral diarrhea virus, bovine coronavirus, bovine adenovirus, bovine respiratory syncytial virus, bovine herpes virus-1, and bovine para influenza virus-3 were 20.00, 14.78, 5.21, 0.86, 0.00, and 0.00%, respectively. Three animals (2.60%) had a simultaneous infection with two viruses. Detection of bovine viral diarrhea virus, bovine coronavirus, and bovine adenovirus was correlated. The virus infection rates were 31.81 and 44.66% in five sampled cities. The virus detection rate in infected animals was related to the nose (26 animals; 50.09%), nose and eyes (seven animals; 15.90%), eyes (seven animals; 15.90%), nose, eyes, and blood (three animals; 6.81%), and blood (one animal; 2.27%) samples. The virus detection rate in different samples was in separate clusters. Monitoring and controlling the circulation of bovine viral diarrhea virus and bovine coronavirus in the central desert of Iran is vital due to the high detection rate. Our results highlight the necessity of investigating other viruses and bacterial agents related to the BRD in the study area.

Abstract This study was conducted in West Azerbaijan province, Iran (37°27'18.022" N, 45°0'0" E) to investigate the genotyping and phylogenetic characterization of Mannheimia haemolytica in cattle and buffaloes from November 2022 to January 2024. Mannheimia haemolytica is a bacterium known to cause pasteurellosis pneumonia, a respiratory disease in ruminants, such as cattle and sheep. This is one of the main causes of economic losses in the feedlot industry. In addition to the deaths, treatment costs are also significant. The lung and nasal swab samples were collected from 378 cattle and buffaloes. The M. haemolytica was detected in 32 (8.46%) of the samples, with a notably higher isolation rate from lung tissue (56.25%; n = 18) compared to the nasal swabs (43.75%; n = 14). Interestingly, the study also revealed a seasonal pattern, with the highest isolation rates observed during January, February, and March. Multi-locus sequence typing demonstrated that all isolates belonged to sequence type 1 (ST1) within clonal complex 28. This finding is consistent with the global prevalence of ST1 in bovine isolates, indicating widespread distribution. Phylogenetic analysis revealed a strong correlation between ST1 and STs 30 and 54, highlighting the prevalence of ST1 in M. haemolytica among ruminants in West Azerbaijan, Iran. Further research is needed to investigate its potential for causing disease and its transmission pattern.