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25 Cards in this Set
- Front
- Back
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What are the important members of the genus orthopoxvirus?
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Variola (smallpox), vaccinia, monleypox, and cowpox
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Describe the replication of poxviruses inside the cell
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The replication is cytoplasmic and produces new virions with a lytic infection
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Describe the structure and the genome of the poxviruses
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They are large, complex viruses with a distinct outer membrane and contain a dsDNA genome
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Describe the polymerase of poxviruses
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They have a structural viral RNA polymerase and a non-structural viral DNA polymerase
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What are the three important genus members of the poxvirus family?
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Orthopoxvirus, parapoxvirus, and molluscipox
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What is important about orthopoxviruses concerning the ability to vaccinate against them?
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All members of this genus exhibit cross-reactivity of surface antigens and are cross-protected by neutralizing antibodies
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Describe the viruses of the genus parapoxvirus?
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These are zoonotic agents generally from domestic animals that cause "contagious pustular dermatitis" (orf virus) and "milker's nodes"
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What viral condition is caused by a member of the molluscipox family?
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Molluscum contagiosum is caused by the human molluscum contagiosum virus
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What diseases are caused by orthopoxvirus members?
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Smallpox (variola major) and monkeypox
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Describe how the outbreak of monkeypox occured in the US in 2003. Describe the clinical presentation
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The disease was transmitted from a giant gambian rat to prairie dogs, which infectced humans bitten by the prairie dogs; Patients presented with a rash, fever, chills and sores which lasted 2-4 weeks and was not fatal
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Describe the lesions of the orf virus and name it's family; how is it contracted?
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The orf virus is a parapoxvirus that causes contagious pustular dermatitis and is acquired from sheep or goats with "sore mouth" disease
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What causes "milker's nodes?"
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A parapox virus infection obtained from infected cows that presents with nodular lesions
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Describe the lesions caused by molluscum contagiosum virus, especially in AIDS patients
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The lesions are localized dome-shaped and often umbilicated; they are very extensive in AIDS patients
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Describe the transmission of the molluscum contagiosum
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It is generally transmitted sexually and may lead to a more generalized infection in AIDS patients
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How is the smallpox virus (variola) transmitted and how long is the incubation period?
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It is transmitted by respiratory secretions as well as shed from the vesicles and scabs; it generally incubates for 10-14 days (non-infectious in this period)
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Describe the lesions of smallpox and how they progress
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The lesions first present in the mucous membranes of the mouth/throat and then face, which spread to the trunk and extremities; they progress in a synchronous fasion from vesicle to pustule to scab
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What happens before the begining of smallpox infection?
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There is a febrile prodrome that lasts for 1-4 days with nausea, headache
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How can chickenpox be differentiated from smallpox?
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Chickenpox spreads from lesions on the trunk to the head and limbs with lesions at different stages present; smallpox lesions spread from the face to the trunk and prorgess in a synchronous fasion
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What are some factors as to why variola virus able to be eradicated?
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It has cross-reactivity with surface antigens from the other orthopoxviruses, no animal reserviors, lack of antigenic variation, lakc of respiratory transmission prior to eruption of lesions, and acquisition of life-long immunity from natural infection
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How was the previous (older) vaccine for variola made and how is the newer version made?
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The old version was vaccinia virus prepared from lymph of inoculated cattle and the new version is produced in cell culture using a monkey kidney cell line (both are live vaccinia virus!)
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What complications of the smallpox vaccine have arisen and what therapy is used to treat them?
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Postvaccinal encephalitis, eczema vaccinatum, progressive vaccinia (vaccinia necrosum), generalized vaccinia, myopericarditis, and autoinoculation of the eyes; cidofovir and vaccinia immune globulin (VIG) have been used to treat these complications
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Who usually obtains complications of smallpox vaccination?
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Immunocompromised people or those with eczema following primray immunization or physical contact with someone recently immunized
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What virus species are used as live-recombinant vaccines or expression vectors for recombinant genes?
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The canarypox viruses and recombinant vaccinia
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How is vaccinia virus used in rabies immunization?
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A recombinant live vaccinia virus encoding rabies glycoproteins is used for oral immunizaiton of wildlife
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Why are canarypox viruses used as a recombinant form of vaccination to express genes from other viruses?
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Canary viruses are restricted in their host ranges and do not replicate in human or other mammilian cells
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