• infect both vertabrates and invertablrates
• enveloped
• large brick shaped virus
  • short surface tubules/filaments
• large, complex genome
  • linear, dsDNA

potential bioterrorism

• viruse attach to membrane and fuses with host cell
• early gene expression, DNA replication, followed by intermediate and late gene expression
• progeny DNA molecules, virons enzymes, and structural proteins assemble to form the previrion particles (mature virions- MV)
• membranes added in Golgi (wrapped virions- WV)
• outermost LP layer fuse with plasma membrane releasing enveloped virus (EV)

• captured cellular genes which modulate the host immune response
• modified versions of receptors for cytokines or chemokines called "viroceptors"
  • secreted or located in infected cell surface

All homologes to cytokines

• smallpox
• molluscum contagiosum
• Orf

• has been eradicated
• humans are only reservoir (makes it easy to erradicate)
• person to person transmission via aerosolized route

• after inhalation, virus replicates in local LN followed by brief viremia then latent period

• incubation period: 7-17 days
• prodrome: abrupt onset of malaise, high fever, vomitting, and severe headache
  • some get delirium during prodome phase
• 2-3 days later vesicular rash appears
  • start on face, hands, forearms (peripheral)
  • mucouse membrane lesions may also happen
  • spread to trunk and lower extremities
• lesions progress from papules to vesicles to pustules
  • umbilicated centers
  • more commonly involve extremities
• lesions are predominantly at same stage of development
  • eventually crust although scabs may still cotain infectious virus
  • lesions leave scares after separation of crusts
• fatal
• rash lasts 5-8 days

• variola major (TYPICAL)
• variola minor- rarely fatal with fewer lesions
  • previously vaccinated
• flat (malignant) smallpox
  • very fatal
  • flat lesions that eventually coalesce
• hemorrhagic smallpox
  • uniformly fatal
• variola sine eruptione
  • mild with no rash
  • previously vaccinated or infants with maternal Ab

• chickenpox
  • infectious period 3 days before rash onset
  • rash in dffirent stages
  • rash progress from scalp, trunk to extremiites
  • tx-acyclovir
  • low mortality
  • vaccine: 12-15 months
• smallpox
  • infetctious period when rash disappears
  • rashes are in same stage and umbilicated
  • rash starts at hands, face and progress to trunk
  • tx: experimental
  • high mortality
  • vaccine in high risk groups

• highly contagious
• similar incubation period
• nosocomial transmission

• clinical specimens should be processed in BSL facility
  • let lab know
• transport fluid, scabs in sealed container
• electron microscopy
• cell culture or on chorioallantoic egg membrane
• PCR based

• isolation: airborn and contact
  • communicacable from onset of rash until 7-10 days
  • isolated untile scabs separate
• tx: no known specific therapy (try cidofovir cause it does work in vitro)
• smallpox vaccine
  • live viral vacine (cowpox)
  • vaccinate pts with early diseas

• reservoir hosts are rodents
• ocassional spread to cats, cows, humans
• transmission to humans
  • contact with infected teats of milking cows
  • currently, infection is more commonly among domestic cats
• localized pustular lesion at site of their introduction into the skin
• source of vaccinia virus/smallpox vaccine

• vaccine licensed as safe in humans
• large portion of genome is nonessential
• vaccinia DNA has many restriction enzyme sites
  • foreign genes can be incorperated into vaccina
  • expressed once incorperated into host genomes

• epidemiology
  • sporadic cases and outbrakes
  • Asian buffalo in Pakistan, India, Bangladesh, Russia, Indonesia, Egypt, Italy
• pox lesions on udder
• human infection
  • transient fever
  • regional lymphadenitis
  • pock lesions
  • usually on hands, from contact with infected bufallo

• naturally only found in Africa
  • DRC, Liberia, Sierre Leone, Nigeria, Benin, Cameroon, Gaboon, Cote D Ivoire
• monkeys and man are incidental host
• acquired via animal contact
• reservoir: rodents
• mostly acquired by children in rural reas
• contact with small animals and person to person contact possible

• similar rash to smallpox, but unlike smallpox, but assoicated with lymphadenopathy
• mortality less than smallpox
• tx similar to smallpox: cidofovir
• smallpox vaccine usually can protect against it (85%)

• benign, self limited papular rash
• higher incidence in kids, sexually active adults, and immuncompromised (ex: HIV)
• single or multiple umbilicated skin papules
  • kids: face, trunk, extremities
  • adults: genitals
• person to person transmission
  • direct skin contact
  • fomites have been implicated
    

• discrete smoooth dome shaped lesions
• incubation: 14-50 days
• skin colored with opalescent caracter
• central depresion or umbilication
• contain a white, waxy curd like core
• size is variable, depending upon stage of development

• usually self limited in immunocompetent
• evisceration or removal of umbilicatd core (tape stripping)
• cryotherapy
• topicals
  • podophyllin and podofilox (also used for genital warts)
  • trichloroacetic acid
  • imiquimod (TLR7 agonist)
  • cantharidin
  • tretinoin

• epidemiology
  • mostly anima infection of sheep and goats
  • esp. in Europe, New Zeland
• transmitted to humans by contact with infected animals (livestock workers, meat handlers)
• lesions on hand
• reddish nodules that may form vesicles, pustles, or ulcerate
• may self heal in 3-6 weeks