DNA Viruses Flashcards
How is variola (smallpox) transmitted?
Respirtaory route or contact with lesions
What diseases/symptoms are associated with Parvovirus B19?
Erythema infectiosum (cold-like symptoms with slapped check rash and lacey rash on trunk and extremities), aplastic anemia, arthritis
How is parvovirus diagnosed, treated, and prevented?
Diagnosed based on clinical appearance and serology, if necessary. Treatment is symptom management and blood transfusion in cases of severe anemia. No vaccine is available.
What is the clinical progression of HHV-6 & HHV-7 infection?
Incubation period, followed by abrupt high fever. WHen the fever subsides, rash appears. Recovery without complication.
What disease is associated with JC virus?
Progressive multifocal leukoencephalopathy (PML). JCV crosses the blood-brain barrier and leads to demyelination. This is most common in AIDS patients.
How is HBV diagnosed, treated, and prevented?
Diagnosed by clinical presentation, serology, PCR.
Treated with HBV immunoglobulin and antiviral drugs.
Prevention with recombinant vaccine that induces response to HBsAg.
What tissues are typically infected by Polyomavirisues?
Tonsils & lymphocytes with spreading to the kidneys
How is molluscom contagiosum transmitted?
Skin-skin contact or fomites
What viruses belong to the Alpha Herpesviruses Family?
Herpes simplex virus 1 (HSV-1), Herpes simplex virus 2 (HSV-2), Varicella-zoster
What cells are commonly infected by Herpesviruses alpha viruses?
Mucoepithelial cells, fibroblasts, T cells
What clinical diseases are associated with HHV-8/Kaposi’s sarcoma?
Kaposi sarcoma, primary effusion lymphoma, multicentric Castleman’s disease (multiproliferative lymphadenopathy)
What Polyomavirisues are associated with human infection?
JC virus & BK virus
How is Varicella Zoster transmitted?
Respiratory route
What are the characteristics of Poxviruses?
Enveloped, dsDNA virus with a complex capsid. Replication occurs in the cytoplasm
What cells are commonly infected by Herpesviruses beta viruses?
Leukocytes, epithelial cells, fibroblasts, lymphocytes
You’re beta are HHV 6, HHV 7 and CMV
What types of adenoviruses are associated with more severe infections of the lower respiratory tract?
Types 4, 7, & 14
What is the only DNA virus that is not double-stranded?
Parvoviruses
How is smallpox prevented?
Live, attenuated vaccinia virus, scratch with bif. needle
What cells are typically infected by Papillomavirisues?
Epithelial cells of skin & mucosal membranes
How is adenovirus diagnosed, treated, and prevented?
Diagnosis by culture, PCR, or antibody titers. Treatment with symptom management. Live-nonattenuated oral vaccine, provided typically only in the military
How is HSV transmitted?
Contact with bodily fluids or skin-skin contact
How are Polyomavirisues spread?
Inhalation or fecal/oral
Parvovirus can cross the placenta. What is the result on the developing fetus?
First trimester - fetal death
Second trimester - hydrops fetalis
What is the most common Papillomavirisus?
Human papillomavirus (HPV)
To what receptor does Epstein-Barr virus bind?
CR2/CD21 & MHC II on B cells
What diseases/symptoms are associated with Cytomegalovirus (CMV) infection?
Mononucleosis-like syndrome, pneumonia, encephalitis, retinitis, colitis, esophagitis, cytomegalic inclusion disease (hearing loss, visual impairment, and mental retardation in infants)
What are the characteristics of Herpesviruses?
Enveloped, icosahedral dsDNA virus. Three subfamilies - Alpha, Beta, Gamma.
What virus is the leading cause of viral encephalitis?
HSV-1
Where does HSV-1 remain dormant?
Neuron in the trigeminal ganglion
What virus is associated with chicken pox?
Varicella Zoster
How is adenovirus diagnosed, treated, and prevented?
Diagnosis by culture, PCR, or antibody titers. Treatment with symptom management. Live-nonattenuated oral vaccine, provided typically only in the military
What are the characteristics of adenoviruses?
Naked, icosahedral, dsDNA virus
What disease is associated with BK virus?
Hemorrhagic cystitis
How is HBV transmitted?
Sexually, IV drug use, mother to baby during birth
What are the characteristics of Papillomavirisues?
Naked, icosahedral dsDNA virus
What is the only DNA virus to not replicate in the nucleus?
Poxviruses
How are Papillomavirisues spread?
Direct contact, contaminated fomites, sexually transmission, neonatal exposure during birth
What infection is associated with HSV-1?
Oral herpes
Where does HSV-2 remain dormant?
Neuron in the sacral dorsal root ganglion
HPV is capable of causing lytic, latent, and transforming infections. How does HPV cause a transforming infection and what is the result?
HPV can integrate into the host genome. Viral DNA is not replicated by HPV oncogenes are expressed. This can lead to the transformation of cells and carcinoma.
HHV-8 is typically asymptomatic in immunocompetent patients. What symptoms are present during primary infection with HHV-8 in immunocompromised patients?
Fever, splenomegaly, lymphoid hyperplasia
How is monkeypox treated and prevented?
Tecovirimat – approved for treatment of smallpox; inhibits release of new viral particles
Vaccinia Immune Globulin Intravenous (VIGIV)
Cidofovir – used for CMV retinitis; shown to be effective against orthopoxviruses inin vitroand animal studies; inhibits viral polymerase
Brincidofovir – approved for use in smallpox; polymerase inhibitor
JYNNEOS vaccine – live, attenuated non-replicating orthopoxvirus
What cells are commonly infected by Herpesviruses gamma viruses?
B cells, epithelial cells, endothelial cells, monocytes
What clinical disease is most commonly associated with Epstein-Barr virus?
Mononucleosis
What viruses belong to the Beta Herpesviruses Family?
Cytomegalovirus (CMV), Human herpesvirus 6, Human herpesvirus 7
How does HBV replicate its genome?
Using a RNA-dependent DNA polymerase with RNAase activity
What diseases/symptoms are associated with adenovirus infection?
Pharyngitis, conjunctivitis, pharnygojunctival fever, gastroenteritis
What symptoms are associated with HPV infection?
Cutaneous warts, genital warts, laryngeal papillomas, carcinoma of cervix, penis, and anus
What are the medically significant Poxciruses?
Variola, Monkeypox, Mulluscum contagiosum virus
What types of adenoviruses are associated with gastroenteritis in children?
Types 40 & 41
How are adenoviruses transmitted?
Respiratory route
To which receptor do adenoviruses bind?
Coxsackievirus Adenovirus Receptor (CAR), which is a cell-adhesion molecule, and integrins
Why is it that poxviruses remain in the cytoplasm and do not enter the nucleus?
Poxviruses encode their own DNA-dependent DNA polymerase and DNA-dependent RNA polymerases. This means they do not need to use host machinery in the nucleus.
What cells are targeted for infection by parvoviruses? How do they enter the cell?
RBC precursors (erythroblasts) - entry by binding the erythrocyte P antigen
What is coded for by HBV gene C?
Core protein (HBcAg) & secreted protein (HBeAg)
What is the only known human parvovirus?
Parvovirus B19
What are the characteristics of parvoviruses?
Naked, icosahedral ssDNA virus
What are the characteristics of Hepadnaviruses?
Enveloped, partially dsDNA virus. Dane particle is infectious
What Herpesviruses are generally asymptomatic during the primary infection?
CMV, HHV-6, HHV-7, EBV, KSHV
What is coded for by HBV gene S?
A surface glycoprotein (HBsAg). This glycoprotein is the target of antibodies for immunity
How is parvovirus B19 transmitted?
Respiratory route
How are HHV-6 & HHV-7 transmitted?
Saliva
What symptoms are associated with molluscom contagiosum infection?
White, pink, or flesh-colored dome-shaped papules with a central depression
How is HPV diagnosed, treated, and prevented?
Diagnosis with Papanicolaou (Pap) smears and PCR.
Treatment of symptoms (wart removal).
Nine-valent vaccine - yeast cells expressing a capsid protein
What viruses belong to the Gamma Herpesviruses Family?
Epstein-Barr virus (EBV), Kaposi’s sarcoma herpesvirus (KSHV)
What is the shape of all DNA viruses?
Icosahedral
What virus is the leading cause of viral pharyngitis?
Adenoviruses
Presence of what antibody indicates immunity to HBV?
Anti-HBsAg
How is HBV released from cells?
After replication, HBV buds into the ER or pre-golgi and picks up an envelope with HBsAg. Progeny are then released via exocytosis. HBeAg is secreted by infected cells and not incorporated into the viral genome.
What cells do adenoviruses infect?
Mucosal epithelial cells in the upper respiratory & GI tracts
How are Polyomavirisues diagnosed, treated, and prevented?
Diagnosis with urine tests, PCR, biopsy, MRI, or CT. No treatment or vaccine.
Genital herpes is most commonly associated with what virus?
HSV-2
How is Cytomegalovirus transmitted?
Bodily fluids, sexual transmission, blood transfusion, organ transplant, breast milk
How does HSV enter latency?
The virus travels up the axon to the ganglion. Latency-associated genes are expressed. Stress or another factor may trigger viral replication in the neuron. New viral particles travel down the axon to the site of the primary infection and infect epithelial cells.
True/False. All DNA viruses encode their own DNA-dependent DNA polymerase.
False. Most DNA viruses encode a DNA-dependent DNA polymerase, with the exception of Parvoviruses.
A patient presents with acute EPV infection. What is the expected serology?
VCA antibody, but no EBNA antibodies. If the infection persists, VCA IgG & EBNA antibodies can be expected.
What is the most common cause of congenital viral disease?
Cytomegalovirus
How are HSV & VZV diagnosed, treated, and prevented?
Diagnosis with Tzanck smear, viral culture, PCR, serology.
Treated with antivirals or C-section to prevent neonate exposure.
Attenuated, live AZV vaccine.
What are the properties of Polyomavirisues?
Naked, icosahedral, dsDNA virus, ubiquitous and asymptomatic in immunocompetent persons
Where do Herpesviruses alpha viruses remain latent?
Neurons
How is monkeypox transmitted?
Contact with fluid from lesions, skin-skin contact, fomites
Where does varicella virus go latent?
Dorsal root ganglion of the neuron. Reactivation causes shingles.
