[Retrospective analysis of cases with a diagnosis of cerebrocortical necrosis and its relation with type 5 bovine herpesvirus].

In order to demonstrate the association of bovine herpesvirus type 5 (BHV-5) and cerebrocortical necrosis (CCN), 89 such cases were examined in cattle from three regions of Buenos Aires Province, Argentina, registered between 1970-1999. Hematoxylin-eosin staining and BHV-5 in situ hybridization were performed on paraffin-embedded neural tissues. The severity of microscopic lesions was scored according to a 0-3 scale. Morbidity, mortality and lethality rates between groups depending on age and regions were determined. The highest prevalence of CCN was detected between 1979 and 1984, particularly during the spring. Differences in morbidity and mortality rates between groups of age and regions were not detected (P > 0.05). Amaurosis (48%), ptyalism (42%), circling (40%), ataxia (36%) and bruxism (37%) were frequently observed. Lesions were predominantly found in anterior and posterior cortex (90.6%) and diencephalon (36.5%). Meningitis and perivascular cuffing (94.4%) and focal (78%) or diffuse (73%) gliosis were predominant in cerebrum. Focal necrosis was observed in 66.6% of cases. BHV-5 was isolated from 9/19 cases since 1992 and BHV-5 DNA was detected by in situ hybridization in 3/9 cases. No virus was identified in brain tissues with severe lesions. These findings indicate the association of BHV-5 in neurological disease previously reported as CCN.