Chapter 27: Herpesviridae

The Herpesviridae family comprises a group of double-stranded DNA viruses unified by characteristic morphological features and a remarkable capacity to establish persistent latent infections within host tissues. This chapter provides a comprehensive clinical examination of the major human pathogens within this family and their diverse disease manifestations. Herpes Simplex Virus types 1 and 2 serve as paradigmatic examples of herpesviruses, demonstrating how these agents cause recurrent mucosal infections, particularly labial lesions, while maintaining dormancy within sensory nerve ganglia between symptomatic episodes. Varicella-Zoster Virus presents a distinct epidemiological pattern, causing primary infection as chickenpox during childhood and persisting in dorsal root ganglia to emerge decades later as herpes zoster, characterized by dermatomal distribution and severe neuropathic pain. Cytomegalovirus receives extensive attention due to its serious consequences in immunocompromised populations, including patients undergoing bone marrow transplantation who face significant risk for interstitial pneumonia and individuals with advanced HIV disease experiencing progressive visual impairment from retinal infection. The chapter outlines contemporary diagnostic approaches, including conventional cell culture techniques, examination of infected cell preparations for characteristic inclusion bodies, immunological antigen detection methods, and molecular amplification strategies. Epstein-Barr Virus illustrates the transformative potential of certain herpesviruses, linking viral infection to lymphoproliferative disease and malignant lymphoma development, while also causing acute infectious mononucleosis. The classification and basic characteristics of Human Herpesvirus 8 complete the discussion, representing newer additions to the characterized herpesvirus genus. Throughout the chapter, the recurring theme of viral reactivation in immunocompromised hosts underscores the clinical importance of understanding herpesviruses as chronic infections rather than acute, self-limiting diseases.