DNA Viruses

Question 1

General

Answer 1

ds, linear
Icosahedral capsid
Envelope

No envelope: adeno, parvo, papilloma
ss: parvo
Brick-shaped capsid: variola

Question 2

Adenovirus

Answer 2

Stealth gene
Fecal/oral or resp droplets
Fever, sore throat, coryza
Sore throat + conjunctivitis = adeno
Epidemic keratoconjunctivitis: pseudomembrane and acute watery discharge
May deactivate pertussis
Self limiting, supportive care
Live vaccine

Question 3

Parvo Erythrovirus B19

Answer 3

Infect rbc 
Resp droplets, max shedding before sx 
TORCH
anemia
Fifths disease/erythema infectiosum: slapped cheek rash to lacey rash
Acute arthritis

Question 4

Variola

Answer 4

Brick-shaped capsid
Lipid envelope
Human reservoir 
Resp droplets
Replicates entirely within cytoplasm
Prostration, synchronous maculopapular rash that spreads to trunk
Vaccina virus

Question 5

Papilloma

Answer 5

Circular DNA
cannot grow in culture
Sexually transmitted or skin contact
Warts (cutaneous, oral, anogenital)
Cervical dysplasia 
Higher # or CIN increases risk of cancer
Koliocyte cells
E6/7 binding to pRB/p53 blocked and loss of E2 function
Vaccine: Gardasil, 6 11 16 18

Question 6

Herpes Simplex I/II

Answer 6

Tegument: proteins b/n capsid and envelope
Human reservoir
Direct contact
TORCH
LATENCY
Primary: vesicular lesions
Secondary: prodrome, more mild
Orofacial: trigeminal
Genital: sacral dorsal ganglia
#1 cause of encephalitis 
Self limiting unless severe use acyclovir

Question 7

Varicella-Zoster

Answer 7

Envelope unique inverted repeats of DNA
Tegument
Chickenpox highly contagious, rash begins on scalp to trunk and is asynchronous and itchy,
TORCH
shingles reactivation from ganglia, dermatomal, painful rash
Self limiting, do not give aspirin (reye’s syndrome), severe shingles acyclovir
Live attenuated vaccine

Question 8

Cytomegalovirus

Answer 8

Envelope unique inverted repeats of DNA
Tegument
Sex contact,bodily secretions, daycare
TORCH
Most a symptomatic 
Greatest risk in first two trimesters, organ transplant, immunosuppressed
Mono-like, intranuclear inclusions( owls eye), deafness in congenital, retinal damage in AIDS, hepatitis 
Gancyclovir, foscarnet, cytogam

Question 9

Epstein-Barr virus

Answer 9

Envelope unique inverted repeats
Tegument
Through salvia
Targets epithelial cells
EBV goes latent in B cells and become immortalized, secrete monoclonal Ab (use heterophile Ab for diagnosis)
Extreme fatigue, retroorbital ha, pharyngitis, cervical lymphadenopathy, undulant fever with night sweats, splenomegaly
No sports-> splenic rupture, hairy leukoplakia (AIDS), burkitt’s lymphoma (Africa/papa New Guinea), nasopharyngeal (Chinese ancestry)
Do not give ampicillin

Question 10

Hepatitis B virus

Answer 10

Reverse transcriptase
Bodily fluids
Human reservoir
HbSAg: surface Ag, active infection
HbEAg: active and infectious
HbCAg: just prior to active disease
Replicates in liver, damage (by immune system)
Strong CTL response acute, weak chronic
Young asymptomatic but chronic, older symptomatic but not chronic
Urticaria (itching wheals), arthralgia, dark urine, steatorrhea, jaundice
Fulminate with HDV
Chronic leads to cirrhosis/carcinoma, hepatic failure
No steroids
Recombinant vaccine: HbSAg

Question 11

Hepatitis B Serology

Answer 11

Acute: HBsAg/HBeAg/ HBV-DNA and HBcAb IgM
Window: HBcAb IgG and HBeAb
Prior Infection: HBcAb IgG and HBeAb and HBsAb
Immunization: HBsAb
Chronic Infection: HBsAg/HBeAg/HBV-DNA and HBcAb IgG