Snapshot A 17-year-old patient presents to your clinic with a new rash. He is a wrestler on his high school varsity team. The rash is mildly itchy, but the patient denies any oozing or bleeding. On exam, you note umbilicated, waxy spots along his neck, arms, and waist in a nonspecific pattern. What are the characteristics of the most likely virus affecting this patient? DNA Virus Table Enveloped DNA Viruses Virus Disease Treatment Herpesvirus Herpesvirus Herpesvirus HSV type I Gingivosomastitis/herpes labialis (lip lesions) Keratoconjunctivitis Temporal lobe encephalitis Acyclovir HSV type II Genital vesicles Neonatal herpes Acyclovir Varicella zoster Chickenpox Shingles Acyclovir Epstein-Barr Infectious mononucleosis Burkitt lymphoma Nasopharyngeal carcinoma Treat symptoms Cytomegalovirus Mononucleosis Cytomegalic inclusion disease Pneumonia Ganciclovir HHV Type 6 Roseola (fevers, seizures, rash) Treat symptoms HHV Type 8 Kaposi's sarcoma None Herpesvirus Hepadnavirus Herpesvirus Hepatitis B Hepatitis IFN Lamivudine Poxvirus Poxvirus Poxvirus Variola Smallpox No known treatment (30% mortality) Molluscum contagiosum Molluscum contagiosum (wart-like benign tumors) Self-limiting Ritonavir Non-Enveloped DNA Viruses Virus Disease Treatment Adenovirus Adenovirus Adenovirus Adenovirus Acute respiratory disease Pharyngoconjunctivitis Epidemic keratoconjunctivitis Gastroenteritis (pediatric) Self-limiting Papillomavirus Papillomavirus Papillomavirus Human papilloma virus Warts Cervical intraepithelial neoplasia Treat with cryotherapy Polyomavirus Polyomavirus Polyomavirus JC virus Progressive multifocal leukoencephalopathy (PML) Supportive Parvovirus Parvovirus Parvovirus Parvovirus B19 Erythema infectiosum Aplastic crisis (in sickle cell) Hydrops fetalis Self-limiting or immunoglobulin for aplastic crisis Introduction to Viruses Viruses are obligate intracellular infectious agents with the following basic components DNA or RNA never both capsid a protein coat that surrounds the genetic material icosahedral or helical symmetry made of capsomers login to view 3 more bullets sometimes an envelope Viruses are classified by nucleic acid DNA or RNA double stranded or single stranded (+) positive or (-) negative stranded RNA single or segmented pieces of nucleic acid complexity of genome capsid icosahedral or helical envelope naked login to view 1 more bullet enveloped login to view 1 more bullet size diameter or number of capsomers ploidy all viruses are haploid (1 copy of DNA or RNA) except retroviruses login to view 1 more bullet infectivity of purified nucleic acid purified nucleic acid that is intrinsically infectious login to view 6 more bullets purified nucleic acid that is NOT intrinsically infectious login to view 4 more bullets DNA Viruses Most DNA viruses are double-stranded (dsDNA, like human DNA) have icosahedral symmetry replicate in the nucleus are linear Exceptions parvoviridae only 1 strand of DNA (ssDNA) poxviridae no icosahedral symmetry login to view 1 more bullet replicates in cytoplasm papilloma, polyoma, and hepadna are non-linear (circular) Enveloped vs naked 3 DNA viruses are enveloped herpes hepadna pox the rest are naked The DNA viruses are "HHAPPPPy" herpes hepadna adeno pox polyoma papilloma parvo