polio, rabies, viruses, prions, Flashcards
Compare and contrast Salk and Sabin vaccines. Diagnose diseases caused by Coxsackie A and B viruses and enteroviruses. Diagnose rabies from clinical presentation and lab findings. Recommend treatment for rabies. Identify neurological syndromes caused by JC, measles, and rubella viruses. Compare and contrast viruses and prions.
morphology of rabies virus
rod shaped enveloped RNA virus
type of virus causing rabies
rhabdovirus
route of rabies transmission from wound to brain
nerve endings –> dorsal root ganglia –> Spinal cord –> brain
parts of the brain infected by rabies
brain stem, hippocampus, cerbellum
how virus moves up neurons
axonal transport
rabies virus spreads from CNS to:
salivary glands, kidneys, cornea (highly innervated areas)
factors associated with rabies incubation period
distance of wound to brain
concentration of virus in inolculum
severity of wound
host age and immune status
immune response to rabies infection
neutralizing antibody is protective
cell mediated responses not effective
inflammation response to infected (non-nervous) tissue
none
major resirvoirs of rabies
domestic animals, cattle, small carnivorous mammals
non-animal bite possible rabies tranmission mode
cornea/organ transplants
lab diagnosis of rabies
cytoplasmic negri bodies in neurons
viral RNA in skin or CNS by PCR
viral antigen in skin or CNS by IF
treatment of rabies exposure
killed virus vacciene before sx occur
diseases caused by slow viruses (5)
progressive mutifocal leukoencephalopathy subacute panencephalitis subacute measles encephalitis progressive rubella panencephalitis AIDS
prion diseases
Kuru CJD gertsmann-straussler syndrome scrapie BSE
virus causing PML
papovavirus (JC virus)
clinical signs of PML
cerebral sx (confusion, dementia, aphasia, visual field defects)
SSPE virus
defective measles virus
sx of SSPE
children: withdrawal, intellectual decline, mycoclonic jerks, visual decline. progresses to vegetative state and death
pathologic features of PML
infection of oligodendrocytes
• multifocal areas of demyelination
• lesions only in white matter of brain
• little or no inflammatory response
risk for PML
immunocompromised pts
pathenogenesis of SSPE
• Measles virus defective in M protein is not properly
assembled
• Virus spreads from cell to cell but is not released
• Viral glycoproteins are not expressed on cell
surface - infected cells not recognized by immune
response
• Scarring and demyelinization of areas of brain
prevention of SSPE
measles vax
clinical features of Kuru
cerebellar ataxia, disarthria
designation of infectious Prion
PrP
SX of PRP
cerebellar dysfunction, slow wave EEG
pathology of PRP
widespread destruction of white matter, lesions located near blood vessels
examples of enterovirus (3)
poliovirus
Coxsackievirus
echovirus
transmissions routes of enterovirus
fecal-oral
respiratiry
icubation period of enteroviruses
2-10 days
poliovirus primarily causes lesions in
grey matter of anterior horns of spinal cord
motor nuclei of pons and medulla
secondary sites of polio lesions
mesencephalon, cerebellar roof nuclei, precentral gyrus of cerebrum
sx of minor polio
(frequently asymptomatic)
low grade fever, malaise, anorexia
sx of abortive polio
fever headache and myalgia hyperesthesias and parethesias stiffness of neck, back, and hamstrings spinal and nucal rigidity superficial and DTR changes
lab findings in abortive polio
CSF similar to asceptic meningitis
sx of paralytic polio
abortive + higher fever arreflexia muscle group weakness flacid, asymmetric paralysis
cranial nerves affected by bulbar polio
IX and X
inactivated polio vx name
salk (injected)
salk vx induces
systemic immunity
live attenuated polio vx name
sabin (oral)
sabin vx induces
systemic and local immunity
sx of acute enteroviral illnes
fever, irritability, lethargy, poor feeding, exanthems, vomiting, URTI, diarrhea
main cause of aseptic meningitis in US
enterovirus
cause of most acute sporadic myocarditis
coxsackie B
precedes myopericarditis
febrile URTI
diagnosis of enteroviral myopericarditis
Echo/EKG
enzymes
PCR
virus causing hand,foot, and mouth
coxackie A16
signs of hand foot and mouth
fever, oral ulcers, vesicles on palms and soles
sx of herpangia
abrupt fever and severe sore throat
hyperemic pharynx
pharynx/mouth vesicles
cause of herpangia
coxsackie A
sx of pleurodynia
abrupt fever and severe chest pain - intensified by movement
may be preceded by malaise, anorexia, and headache
abdominal pain in kids
cause of pleurodynia
coxsackie B
diagnostic test of choice for enterovirus
RT-PCR
morphology of picornavirus
single strand RNA, acid stable
