Causes of equine abortion, stillbirth and neonatal death in central Italy

Abortion, stillbirths and neonatal deaths are an important source of economic loss for the equine industry. Many of the infectious disease agents identified are important from the viewpoint of international trade or public health. The causes of abortion can change over time, as a reflection of improved diagnostic capability or because of background differences in at-risk equine populations. Monitoring and surveillance of the causes of fetal loss over time is therefore important. A total of 67 abortions, 22 stillbirths and 14 cases of neonatal mortality, submitted between November 2004 and July 2011, were examined in this study. Fetuses were subjected to detailed gross examination and the following selected specimens were subjected to histopathological, virological, bacteriological and fungal examination: lung, liver, spleen, thymus, placenta, and stomach contents (the latter only with respect to bacteriological examination). The cause of abortion was identified in 66 cases (64.1 per cent). Of these, infectious agents, including coinfections, accounted for 76 per cent of the diagnoses and 49 per cent of the cases examined. Equine herpesvirus type 1 was the most frequently diagnosed cause of abortion (22 cases), in spite of vaccination against the virus. Twenty cases were bacterial infections and nine cases were placentitis. Noninfectious agents were diagnosed in 19 cases. Umbilical torsion was identified in only six cases. No diagnosis was established in 37 cases (35.9 per cent). While the number of cases investigated in this study is relatively small, they provide baseline data on the causes of equine pregnancy loss in Italy. The percentage of diagnosed cases of abortion, stillbirths and neonatal deaths in foals was lower than previously recorded. Non-infectious causes, especially those frequently reported as a cause of fetal loss, need further investigation. More rigorous examination of placentas should be carried out to identify possible placental disorders. A more extensive surveillance programme of equine abortion, stillbirths and neonatal mortality is needed to improve diagnostic techniques and monitor trends of specific infections. Emerging diseases are unlikely to be recognised in the absence of an ongoing surveillance programme. Greater international agreement on the causes of equine pregnancy loss would facilitate comparison of data from different countries.