skin and wound viruses

Question 1

Variola virus

Answer 1

poxviridae. orthopox genus. Complex, envelopped, dsDNA (does not replicate in nucleus - having DNAdep RNA polymerase)

one serotype. smallPox (variola) bricklike external appearance. eradicated 1977.

human. respiratory droplets or aerosolized fluid from skin or contact with skin lesions or formites.

PATIENT small pox.

• prodrome: flu-like symptoms
• high fever, abrupt (simultaneous erruption) onset of vesicular rash concetrated in face and extremities. macular then vesicular finally burst and crust.

LAB: biopsy demonstrate inclusion bodies, virus, DFA and PCR

TX. symptomatic relief, passive immunity.

PX: live genetically related vaccina virus vaccine. vaccine related cases of encephalitis and progrssive infection.

Question 2

Orf

Answer 2

human infected with sheep/goat pox

poxviridae. papapox genus. Complex, envelopped, dsDNA (does not replicate in nucleus - having DNAdep RNA polymerase)
* dd. antrax lesions, however pox will have less swelling*

Question 3

Cowpox

Answer 3

Vaccina. occupational hazard. localized lesions

poxviridae. orthopox genus. Complex, envelopped, dsDNA (does not replicate in nucleus - having DNAdep RNA polymerase)
* dd. antrax lesions, however pox will have less inflammation*

Question 4

molluscum Contagiosum virus

Answer 4

poxviridae. mulluscipox genus. Complex, envelopped, dsDNA linear (does not replicate in nucleus - having DNAdep RNA polymerase)

Human. direct contact or fomites (towels)

Wart like lesions. hyperplasia of epithelial cells within which cytoplasmic inclusion bodies can be seen.

Incubation 2-8 wks

painless cutaneous clusters of wart, small firm, white/pink/fleshy/pearl bumbs with dimple from which white cheesy material may be expressed. (acanthosis epedermis / hyperplasia)

LAB: PCR. cannot be cultivated. large, eosinophilic, cytoplasmic inclusion bodies in epithelial cells “molluscum bodies”.

TX. spontaneous resolution 2-12 months. or scrap by curettage/liquide nitrogen

Question 5

Herpes Simplex

Answer 5

Herpesviridae. alpha genus (epithelial). Icosahedral, envelopped, dsDNA. surface glycoprotein spikes for attachment

• HSV 1 - oropharyngeal. gingivostomatiis, pharyngitis cold sores ,esophagitis, herpetic whitlow, gladiatorum, encephalitis and meningitis
• HSV 2 - genital with urethritis, to newborn: fatal encephalalitis, keratoconjunctivitis, lesions, (Csection)

cytopathic effect cause change in nuclear structure and margination of chromatin known as cowdry type A intranuclear inclusion bodies. it also causes fusion of clls syncytia formation

Human. contact with viral containing secretions or lesions of mucosal/cutaneous surfaces. transplancetal and delivery.

lifelong infection assymptomatic shedding

phases of infection:

• lytic: infects epithelial cells. actively multiply and kill cells
• latent: retrograde remain inactive in sensory ganglion neuronal cells. (can not find virus but HSV DNA)
• reactivation: anterograde from neurons infect/kill epithelial cells causing recurrent symptoms

primary infections. painful vesicular lesions, fever, malaise, myalgia, regional lymphadenopathy.

Reactivation: less severe painful vesicular lesions, sensory nerve pain, tingling (can preceed lesions), or assymptomatic shedding.

leasions heal without scaring

LAB: tzanck smear demonstrate multinucleated syncytia with intranuclear inclusions cowdry type A in scraping of ulcer base. (not specific)

viral detection with direct immunofluoresscent

PCR to differntiate HSV 1 and 2

TX. antiviral angents relieve symptoms, shorten outbreak but do not eliminate latency. acyclovir (inhibit viral thymidine kinse)

Question 6

Human Papilloma Virus

Answer 6

Papillomaviridae. Icosahedral, naked, dsDNA circular

Human. more than one serotype. direct contact

infects and replicates in squamous epithelial cells of the skin and mucus membrane. induce proliferation causing benign outgrowth. Wart Papilloma

hyperplasia of the prickle cells and excess production of keratong (hyperkeratosis)

• oncogenic: 16, 18. (31 and 45)carcinoma cervix, penis, anus
  • early gene protein coding inactivate tumour suppressors
    
    • E6: inactivates p53
    • E7 inactivates p105RB
• 1,2,3,4 cutaneous warts
• genital warts 11, 6 most common (can be in mouth)

incubtion perios 3-4 mths up to 2 years

LAB: PCR. and papanicolaou smeardemonstrate cytopathic effect of infected cells koilocytes with vacuolated cytoplasm and which are round and occur in clumps.

TX. cutaneous self limiting. or cryo, electrocutery, chemical podofilox.

PX. vaccine guardasil capsid protein HPV 6,11 and 16, 18.