Role of viruses in periodontitis: An extensive review of herpesviruses, human immunodeficiency virus, coronavirus-19, papillomavirus and hepatitis viruses

Table 1 Key information on the human herpes virus types, the main target cells, their oral and systemic pathologies

Human herpes virus	Main target cells	Oral pathology	Systemic pathology
HHV-1 and 2 (HSV 1 and 2)	Mucoepithelial cells (orofacial and genital tract)	Primary herpetic gingivostomatitis. Recurrent herpetic gingivostomatitis. Chronic herpetic gingivostomatitis. Herpes labialis. Increased risk of periodontitis	Genital ulcers
HHV-3 (VZV)	Mucoepithelial cells and T cells (orofacial and any skin or mucosa of the body)	Possible oral vesicles and ulcers, increased risk of periodontitis	Primary infection: Varicella (chicken pocks). Recurrent infection: Herpes zoster (shingles)
HHV-4 (EBV)	Mucoepithelial cells and B cells	Hairy leukoplakia, leukoplakia, nasopharyngeal carcinoma, ulcerations and palatal petechiae, oral lymphoma, increased risk of periodontitis	Infectious mononucleosis, lymphoma
HHV-5 (CMV)	Monocytes, fibroblasts, lymphocytes and epithelial cells	Oral vesicles and ulcers, increased risk of periodontitis	Infectious mononucleosis
HHV-6	T cells, epithelial cells, monocytes, fibroblasts and more	Unknown
HHV-7	T cells, epithelial cells, monocytes, fibroblasts and more	Unknown
HHV-8	Not identified	Ulcers and tumors	Kaposi’s sarcoma

EBV: Epstein-Barr virus; CMV: Cytomegalovirus; HHV: human herpes virus, HSV: Herpes simplex virus; VZV: Varicella-zoster virus.