Thrombocytopenia of < or = 20 x 10(9)/l, a prolonged aPTT > or = 60s, the existence of melena, and somnolence were independent predictors of fatality.

This study confirmed that periodontal human cytomegalovirus and Epstein-Barr virus are associated with major periodontopathic bacteria and with the severity of periodontal disease. The finding of abundant herpesviruses in periodontitis lesions redefines the pathogenic paradigm of the disease. Understanding the interplay between herpesviruses and specific bacterial species in the pathogenesis of periodontitis may form the basis for new approaches to preventing, reducing or delaying tissue breakdown from periodontal infections.

These results support the notion that the clinical outcome of some types of severe periodontal infection depends on the presence of specific herpesviruses and bacterial pathogens. Our findings open the door to testing a variety of hypotheses regarding the deleterious aspects of combined herpesviral-bacterial infections in periodontal sites.

Epstein-Barr virus (EBV), a B-lymphotropic gamma-herpesvirus, causes infectious mononucleosis and oral hairy leukoplakia, and is associated with various types of lymphoid and epithelial malignancies. Saliva is the main vehicle for EBV transmission from individual to individual. Recent studies have also implicated EBV in the pathogenesis of advanced types of periodontal disease. EBV DNA is detected in 60-80% of aggressive periodontitis lesions and in 15-20% of gingivitis lesions or normal periodontal sites. The periodontal presence of EBV is associated with an elevated occurrence of periodontopathic anaerobic bacteria. Moreover, EBV active infection occurs in approximately 70% of symptomatic and large-size periapical lesions. EBV and cytomegalovirus often co-exist in marginal and apical periodontitis. Periodontal therapy can markedly suppress the EBV load in periodontal pockets as well as in saliva, which has the potential to reduce the risk of viral transmission between close individuals. EBV proteins up-regulate cytokines and growth factors, which seem to play a central role in the proliferative response of tongue epithelial cells in oral hairy leukoplakia and in the cell-transformation process of EBV-associated malignancies. Further research is needed to identify the full range of EBV-related diseases in the human oral cavity.