Congenital calvarial and cardiac anomalies in a calf persistently infected with bovine viral diarrhoea virus

Abstract Bovine viral diarrhoea virus is a highly contagious Pestivirus causing reproductive losses and a variety of congenital defects in cattle, affecting organs such as the central nervous system, eyes, bones and heart. This report describes a Holstein Friesian calf persistently infected with ovine viral diarrhoea virus, exhibiting significant malformations of the left frontal bone and sinus, along with a ventricular septal defect. Computed tomography imaging revealed hypoplasia and malformation of the squamous, nasal and orbital parts of the left frontal bone, narrowing the nasal chamber and cranial vault. The left frontal sinus was underdeveloped and replaced by abnormal bony tissue. Postmortem examination confirmed these findings and identified a 15 mm ventricular septal defect, consistent with a systolic murmur and tachypnoea. This case highlights the teratogenic potential of ovine viral diarrhoea virus during fetal development and underscores the virus's role in congenital cranial and cardiac anomalies. It also emphasises the importance of prevention and control programmes to reduce economic losses in affected herds.