E2- Viral infections of the CNS Flashcards
What is the destruction of motor neurons in spinal cord that results in asymmetric flaccid paralysis?
Poliomyelitis
What are the types of clinical syndromes associated with Polio virus?
- Inapparent infection
- Abortive illness
- Nonparalytic poliomyelitis
- Paralytic Poliomyelitis
- Post poli syndrome
What viral infection causes flaccid paralysis from lower
motor neuron damage in less than 1% of infected individuals?
Polio virus
Parylytic poliomyelitis
What viral infection causes muscle weakness, pain, and fatigue 30 or more yrs after infection?
Post polio syndrome in paralyzed polio patients
What causes post polio syndrome?
Remaining motor units of CNS now react to over use and fail
How is polio virus prevented?
Inactivated polio vaccine (IPV)
Live polio vaccine
Now called EIPV
Inactivated polio vaccine (IPV) prevents what?
Disease (paralysis), not infection
What type of vaccine is the Live polio vaccine?
Trivalent oral polio vaccine, OPV (Sabin)
What polio vaccine is used in the US?
Only IPV is employed in US (inactivated polio vaccine)
Last case of paralytic disease in America caused by a ___ virus was decades ago.
Wildtype
What type of virus is polio virus?
Picorna virus (3 antigenic types)
Why is the live polio vaccine (OPV) not given in the US?
Back mutation to wild type
Risk of VAPP (vaccine associated paralytic poliomyelitis) associated with use of the oral vaccine is considered to be unacceptable
If you had not vaccinated them at all, they would probably have never been infected/paralyzed
Arboviruses use what as vectors?
Athropods-borne viruses
Mosquitos and ticks
Birds and small mammals
What are the three groups of arboviruses?
Togaviridae group
Flaviviridae group
Bunyaviridae
What are rare strains of poliovirus that have genetically mutated from the strain contained in the oral polio vaccine?
Circulating vaccine-derived poliviruses (cVDPVs)
What causes St. Louis encephalitis, West Nile virus, Dengue virus, and yellow fever?
Flaviviridae group of arboviruses
What causes California encephalitis virus?
Bunyaviridae group of arboviruses
What are the general clinical manifestations of Arboviruses?
Abrupt onset of fever, HA, vertigo, photophobia, N/V
Confusion and personality changes, focal or general seizures
How is arbovirus dx?
Tests for IgM antibody with CSF or serum (*MAC-ELISA)
What may induce long-lasting positive IgM titers when testing for arboviruses?
Vaccination against Yellow fever and/or Japanese encephalitis
How is arbovirus infection prevention?
Interrupt chain of transmission (mosquitoes)
Eradication of vector
Avoidance of exposure
(Window screens, Insect repellents)
Immunization of nonhuman amplifying hosts (Horses)
How is Zika virus spread?
Mosquitoes and STI (months after infection; male could infect female leading to birth defects)
This the major concern with Zika virus?
Teratogenic potential, also linked to GBS
How is Zika virus dx?
Nucleic acid test (PCR) and MAC ELISA
What does Zika have antigenic cross-reaction with?
Flaviviruses such as Dengue
What have the majority of Zika viruses been associated with?
Travel
Rabies is considered invariably ____ once symptoms are overt
Fatal
What is seen in the excitatory phase of rabies infection?
Furious in dogs
Anxiety
Apprehension hydrophobia (humans only)
Increased salivation/foaming at the mouth from not swollowing
What phase of rabies infection causes coma, hypotension, and death?
Paralytic phase
Exposure to or bite from what animals is sufficient to initiate post exposure prophylaxis?
Skunk, fox, raccoon, or bat*
Kill and examine animal immediately
Exposure to or bite from what animals requires no action because they are rarely infected?
Rodents and rabbits
What type of virus is rabies?
Rhabdovirus
What is pathognomonic for rabies?
Negri body
Retrospective study has revealed the majority of human cases since 1990 have been ____, not linked to bites, but simple contact
Cryptic
What is the tx for clinically overt rabies?
There is no therapy for clinically overt rabies – the “Milwaukee” protocol has failed as often as it has succeeded
How is rabies prevented?
(1) avoidance of exposure
(2) prophylactic vaccination of companion and herd animals, and
(3) immunization after exposure (post exposure prophylaxis consisting of vaccine and hyperimmune serum)
