Updated: 2/4/2018

DNA Viruses

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  • 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
Herpesvirus
Virus Disease Treatment
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
Hepadnavirus
Hepatitis B 
  • Hepatitis
  • IFN
  • Lamivudine
Poxvirus
Variola 
  • Smallpox
  • No known treatment (30% mortality)
Molluscum contagiosum 
  • Molluscum contagiosum (wart-like benign tumors)
  • Self-limiting
  • Ritonavir
Non-Enveloped DNA Viruses
Adenovirus
Adenovirus 
  • Acute respiratory disease
  • Pharyngoconjunctivitis
  • Epidemic keratoconjunctivitis
  • Gastroenteritis (pediatric)
  • Self-limiting
Papillomavirus
Human papilloma virus 
  • Warts
  • Cervical intraepithelial neoplasia
  • Treat with cryotherapy
Polyomavirus
JC virus 
  • Progressive multifocal leukoencephalopathy (PML)
  • Supportive
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
        • polypeptide chains organized into a globular subunit
        • in helical symmetry, capsomers are bound to RNA and coiled
          • forms a helical nucleoprotein capsid
    • 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
        • DNA or RNA + capsomers and other structural proteins = nucleocapsid (no host membrane)
      • enveloped
        • nucleocapsid + host membrane with viral-specified glycoproteins = enveloped virus
    • size
      • diameter or number of capsomers
    • ploidy
      • all viruses are haploid (1 copy of DNA or RNA)
      • except retroviruses
        • retroviruses have 2 identical copies of their ssRNA, approximating diploidy
    • infectivity of purified nucleic acid
      • purified nucleic acid that is intrinsically infectious
        • dsDNA from most viruses
          • except poxviridae
          • except HBV
        • (+) ssRNA from most viruses
          • (+) linear, nonsegmented ssRNA can be translated immediately into a large protein by host machinery
          • virus must carry protease to cleave the 1 large protein product that will be generated by the host machinery
      • purified nucleic acid that is NOT intrinsically infectious
        • (-) ssRNA
          • viruses must carry an RNA-dependent RNA polymerase to generate mRNA the host machinery can read
        • dsRNA
        • they require enzymes contained in the complete virion for infectivity
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
        • surrounded by complex structural proteins
      • 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
 

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Questions (1)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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