DNA Viruses 1

Question 0

Adenovirus disease

Answer 0

Respiratory (cold with fever, laryngitis, cough pneumonia), acute hemorrhagic cystitis, epidemic keratoconjunctivitis, gastroenteritis

Transmission: aerosol, fecal oral, pools

Children and military recruits susceptible

Diagnosis: culture, antigen detection, PCR, serology
Treatment: cidofovir (nephrotoxic)
Vaccine: targets Ad4, only for military

Question 1

DNA viruses

Answer 1

Transcription and replication in nucleus not cytosol

Diversity from recombination between and within genomes

DNA viruses are genetically more stable, DNA polymerase has high fidelity

Replication:
Use host RNA polymerase for mRNA transcription
RNA polymerase and transcription factors (X,Y) recognize viral promoters
Viral transcription factors are virulence factors
Replication via use of host DNA polymerase (in small viral genomes like parvovirus) or replication using viral DNA polymerase (in large DNA viruses like herpes and adenovirus)

Question 2

Adenovirus life cycle

Answer 2

Fiber protein binds to cell receptor
Entry by endocytosis
Endosome acidification causes fibers to lyse the vesicle
Capsid traffics to nucleus and DNA genome uncoats through nuclear pore
Host polymerase II makes mRNA
Early gene expression: transcription factors, DNA polymerase
Late gene expression: structural proteins for capsid
Genome replication by viral DNA polymerase
Capsid assembly in nucleus
Egress by lysis

Question 3

Human papilloma virus disease

Answer 3

Epithelial diseases (warts)
Malignancies (Head and neck, cervical, penile cancer)

Infects differentiated epithelial cells

Host RNA polymerase transcribes viral mRNA
Host DNA polymerase synthesizes viral genomes
Viral factors E6 and E7 are oncogenes

Question 4

HPV diagnosis, treatment, and vaccines

Answer 4

Diagnosis: DNA tests

Treatment:
warts by excision (cryotherapy, chemical ablation, colposcopy)
malignancies with oncotherapy

Vaccines: both are viruslike particles composed of empty capsids
Gardasil
Cervarix