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DNA Viruses (sect.1)
Small Pox Virus
| Question | Answer |
|---|---|
| Small pox History | Samll Pox was world wide in scope, 15 M people infected annually, 2 M died with millions more left disfigured and sometimes blind, 1796-Jenner used cowpox to vac., 1977-Last natural case occured in Samalia, 1980-Smallpox declared eradicated |
| Small pox Characteristics | Largest and most complex virus known, Complex brick-shaped virion, trans. does not occur until onset of rash, by then most are in bed with high fever and malaise, Mortality rate 20-30%, Often fatel disease that results from infection with the variola viru |
| Small pox Diagnosis | Mostly confused with Chicken pox, All Small pox lesions should be at the same stage of development, Chicken pox lesions at different stages-new lesions appear in crops every few days. |
| Small pox Vaccine | Routine vac. in the Us stopped in 1972, Bifurcated(dbl-pronged) needle used to scratch in live virions, Durration of imm. unknown, Assume us pop. is highly susceptible, Encephalitis complication occurs 1 in 30K children and 1 in 200K in adults, |
| Vac. Cont. | Vaccine is helpful postexposure within 4 days, Complications can be severe, but if a person has definitely been in contact with small pox risk is negligible |
| Small pox Primary Vaccination site reaction | In a successful take, a large, scablike develops at the infection site, where it leaves a permanent scar approx. 1 cm |
| Small pox as a biological weapon | Small pox is stable in aerosol form, Stable on surfaces-24 hrs if not exposed to UV lilght, Stable on linens, cloths for extended periods, spreads from person to person by; aerosol expelled from the respiratory system, direct contact |
| Small pox as a biological weapon ( cont) | Fomites: contaminated clothing, ** no known animal or insect resovoir |