Chapter 24: Nonenveloped DNA Viruses

Human papillomaviruses (HPV) demonstrate extreme tissue specificity, targeting epithelial cells of the skin and mucous membranes. High-risk strains like types 16 and 18 are identified as the primary drivers of cervical and other anogenital cancers by producing proteins that disable host cell regulators like p53 and pRb, thereby promoting uncontrolled cell division. Polyomaviruses, including BK and JC viruses, typically establish lifelong latent infections in the kidneys of healthy individuals but can reactivate in immunocompromised patients to cause progressive multifocal leukoencephalopathy or hemorrhagic cystitis. The discussion then shifts to Adenoviridae, characterized by their unique fiber-like projections used for cell attachment. These viruses are frequent causes of acute respiratory distress, particularly in crowded environments like military barracks, as well as epidemic ocular infections and gastrointestinal distress. Finally, the chapter details the Parvoviridae, specifically the B19 virus. As the smallest DNA viruses, they are uniquely dependent on actively dividing host cells, particularly those that produce red blood cells. This reliance explains the virus’s role in causing fifth disease in children—recognized by its distinctive facial rash—as well as severe complications like aplastic crises in individuals with blood disorders and potential fetal damage during pregnancy. Diagnostic and preventive strategies, including the widespread use of HPV vaccines and specialized military adenovirus vaccines, are highlighted as essential tools in managing these persistent viral threats.