DNA Viruses

DNA Viruses Adenovirus – “A Den-O Lions”  Naked linear dsDNA virus o Targets mucosal cells via binding to hemagglutinin  Transmission via respiratory droplets or direct contact or fecal-oral – common in children, military barracks, and people who frequent public pools  Disease includes hemorrhagic cystitis, tonsillitis, and viral conjunctivitis – #1 cause of tonsillitis  Treatment via live attenuated vaccine only for military recruits Papilloma virus – “Pilloma Bugs”  Naked dsDNA virus o HPV encodes E6, 7 which promotes the proteolysis of p53 and RB (tumor suppressors: G1S phase checkpoint and retinoblastoma protein), resp.  Transmission o HPV 1-4 is transmitted via direct contact o HPV 6, 11 is transmitted via vaginal birth for respiratory side effects and via sexual intercourse for anogenital warts o HPV 16, 18, 31, 33 is transmitted via sexual intercourse  Disease o HPV 1-4 is characterized by verruca vulgaris or cutaneous common warts o HPV 6, 11 is characterized by laryngeal papillomatosis or recurrent respiratory papillomatosis and condyloma acuminate or anogenital warts o HPV 16, 18, 31, 33 is characterized by anogenital squamous cell cancer including cervical and penile  Treatment o Prophylaxis via condoms or abstinence or vaccination (Gardasil is effective against HPV 6, 11, 16, 18) o Screening via pap smear showing koilocytes (blue sunny-side up eggs)  Other facts o Most common STD o Buzzword: post-coideal bleeding Polyomavirus JC and BK – “Et Tu, BK?”  Naked circular dsDNA virus o Virus may reside in the kidney and remain latent until a patient becomes immunocompromised  Transmission via respiratory exposure most likely during childhood  Disease o JC virus is characterized by progressive multifocal leukoencephalopathy (PML) or a demyelinating disease seen as non-enhancing multifocal brain lesions o BK virus is characterized by fever and nephropathy including hemorrhagic cystitis  Other facts o JC virus targets people that are immunosuppressed, specifically HIV patients with CD4+ <200 o BK virus targets people that are immunosuppressed, specifically transplant patients Parvovirus B19 – “Bombs Away!”  Naked ssDNA virus o Targets erythroid progenitor cells via P blood group antigen  Transmission via respiratory droplets or vertically (in utero) or blood products  Disease o Children: Fifth’s disease or erythema infectiosum, which begins as a fever that progresses to become a lacy rash o Adult: joint pain, arthritis, and edema in adults o Sickle-cell disease: aplastic anemia o Pregnancy: hydrops fetalis (severe fetal CHF) or spontaneous abortion  Treatment via intravenous IgG and RBC transfusion  Other facts o Smallest DNA virus o Not a part of the TORCHES mnemonic o Buzzword: “slapped cheek rash” Herpes simplex virus (HSV1/2) – “Hermes, the God of Herpes”  Enveloped linear dsDNA herpes virus o HSV1 remains latent in trigeminal ganglia o HSV2 remains latent in sacral ganglia  Transmission o Sexual intercourse o Saliva o Vertical transmission (TORCHES)  Disease o HSV1 is characterized as gingivostomatitis, herpes labialis, keratoconjunctivitis, temporal lobe encephalitis, erythema multiforme, and herpetic whitlow   o HSV2 is characterized as genital herpes, aseptic meningitis Treatment o Prophylaxis (against breakouts) includes acyclovir or valacyclovir Other facts o Intranuclear inclusion (Cowdry) bodies o HSV1 is the number 1 cause of sporadic encephalitis o Herpetic whitlow is more common in dentists (people who have their hands in their mouths) o Tzank smear or skin scraping shows multinucleated giant cells; however, PCR is more commonly used for diagnosis o Buzzword: “dew drops on a rose” rash for HSV1 and “painful and vesicular genital sores” for HSV2 Varicella zoster virus – “Varicella ‘Zeus’-ter Virus”  Enveloped dsDNA herpes virus o Virus remains latent in the dorsal root ganglia and may reactivate during stress or immunocompromised state  Transmission via respiratory droplets and vertical (in utero, TORCHES)  Disease o Infant: congenital varicella syndrome (including limb hypoplasia, cutaneous scarring, and blindness) o Childhood: chicken pox o Adults: shingles, post-herpetic neuralgia (once rash subsides), opthalmicus (V1 of trigeminal nerve is affected) pneumonia, and encephalitis  Treatment via live attenuated vaccine for children or acyclovir; live attenuated vaccine for adults over 60 or acyclovir or famciclovir or valacyclovir  Other facts o Buzzword: “dew drops on a rose” rash o Lesions in different stages of healing o Tzank smear or skin scraping shows multinucleated giant cells; however, PCR is more commonly used for diagnosis o Shingles rash typically does not cross the midline unless a patient is immunocompromised, therefore test patients for HIV Epstein-Barr Virus – “Ye Olde Epstein Bar”  Enveloped dsDNA herpes virus o Targets the B-lymphocytes via binding to CD21 to produce antibodies or for latency  Transmission via respiratory secretions, e.g. saliva  Disease includes infectious mononucleosis (“kissing disease”) – fever, tender cervical lymphadenopathy, splenomegaly, pharyngitis (tonsillar exudates) o Risk factor for cancer: Hodgkin’s Lymphoma, Burkitt’s Lymphoma, and nasopharyngeal carcinoma o Oral hairy leukoplakia (non-cancerous lesion) in HIV patients  Treatment  Other facts o Reactive cytotoxic CD8+ T-cells (atypical Downey cells) are seen on a blood smear o If misdiagnosed for Strep. pyogenes (pharyngitis) and treated with amoxicillin/ampicillin, patient will develop a maculopapular rash o Acutely, there are heterophile antibodies that will agglutinate sheep cells – mechanism used for the rapid monospot test o Patients are at risk of splenic rupture, so make sure that they avoid contact sports Cytomegalovirus – “Cyto ‘Mega-Lo’ Virus”  Enveloped dsDNA herpes virus o Remains latent in mononuclear cells (WBCs with a single nucleus or B/T cells); reactivated when a person becomes immunosuppressed  Transmitted via nearly all means, including a TORCHES infection  Disease o Congenital: blueberry mufÏn rash, jaundice, hepatosplenomegaly, sensorineural deafness, CNS issues, and hydrops fetalis o AIDS patients (CD4 <50): CMV retinitis, vision loss, linear ulcerations in esophagus; colitis with ulcerated walls o Transplant patients: CMV pneumonia  Treatment o Gancyclovir and fascarnet (if virus has the UL97 gene)  Other facts o Congenital CMV is asymptomatic in 80-90% of individuals o Second trimester of pregnancy is the most implicated stage for congenital CMV o Most common fetal-congenital viral infection o Buzzword: “owl’s eye inclusion bodies” o Negative monospot test Hepatitis B – “Hep B Love”  Enveloped circular dsDNA Hepadnavirus virus that replicates both inside and outside of the nucleus, has a reverse transcriptase but is not a retrovirus  Transmission via sexual intercourse, blood products, drugs, and vertical (in utero, TORCHES infection)    Disease includes acute and chronic hepatitis (only 5-10%, much lower in comparison to HCV) o Polyartheritis nodosa (systemic vasculitis), pruritis, arthralgia, kidney damage (glomerulonephritis), hepatocellular carcinoma Treatment o Lamivudine (Nucleoside reverse transcriptase inhibitors) Other facts o Give at risk kids with anti-HB immunoglobulins o Alcoholic hepatitis: AST > ALT, meanwhile viral hepatitis: ALT > AST o HBsAg = live HBV and patient is infected o Anti-HBsAG = patient is immune o HBcAg = confirms HBV infection, recency can be determined by presence or absence of IgM vs. IgG o HBeAg = high viral activity and infectivity o Anti-HBeAg = lower viral activity and infectivity Hepatitis D  Enveloped (-) circular RNA virus that cannot cause any disease without the presence of Hepatitis B – specifically requires the surface antigen (HbSAg) to become infectious. There are two types of infections: co-infection and super-infection.