L84

Question 1

Define encephalitis

Answer 1

Inflam of BRAIN

Question 2

Define meningo-encephalitis

Answer 2

Inflam meninges + brain

Question 3

Define encephalo-myelitis

Answer 3

Inflam of brain + spinal cord

Question 4

Encephalitis presenting symptoms

Answer 4

“Sleepy or acting weird”
Changes in consciousness
Changes in personality
Ataxia

Question 5

Viral causes of encephalitis (usually not 1ary presentation - more likely a 2ary complication)

Answer 5

HSV
Other herpes viruses
Enteroviruses
Measles, mumps, JC

Question 6

How does West Nile present?

Answer 6

1. 80% asymptomatic
2. AMS
   Fever
   Asymmetrical weakness w/ decreased reflexes of all extremities

Question 7

West Nile virus family & genome

Answer 7

Flavi virus (Flavored corona)
\+ssRNA
- Cytoplasmic replication
Icosahedral 
Enveloped - buds out

Question 8

West Nile vector vs resevoir

Answer 8

Mosquito = vector
Reservoir = birds

Question 9

West Nile pathogenesis

Answer 9

Mosquito bites
Infects DCs at skin
Viremia = when get symptoms
CNS penetration + neuron invasion

Question 10

What part of immune system controls West Nile?

Answer 10

Everything!

Need IFN + Ab + cell mediated

Question 11

What genetic variant increases susceptibility to severe presentations of West Nile?

Answer 11

CCR5 delta 32
Butttt gives HIV resistance….
HIV resistance is better than the downsides of getting West Nile

Question 12

What is the most common viral cause of encephalitis in the US?

Answer 12

West Nile

Esp summer & fall when mosquitoes are active

Question 13

West Nile vaccine?

Answer 13

Nope

Question 14

What is the “home grown West Nile”? Describe presentation.

Answer 14

St. Louis Encephalitis

Meningoencephalitis but without the paralysis of West Nile

Question 15

What is the viral family of Eastern & Western Equine viruses? Therefore, describe genome.

Answer 15

Toga
+ssRNA - cytoplasmic replication
Icosahedral
Enveloped - buds

Question 16

Describe the steps in which E&W Equine genome is transcribed.

Answer 16

\+ssRNA parent 
Make non-structural proteins
- Including RNA pol
RNA pol makes -ssRNA from +parent 
-ssRNA codes for 
1. +ssRNA for new viruses
2. mRNA --> codes for structural proteins 

+ssRNA –> structural –> RNA pol & -ssRNA –> +ssRNA & mRNA –> structural proteins

Question 17

Presentation of East Equine virus.

Answer 17

Acute: non-specific fever illness
2-3 days = encephalitis
If you progress to encephalitis, MUCH higher mortality w/ eastern

Question 18

Presentation of West Equine virus.

Answer 18

Asymptomatic or mild fever illness
Small grp develop encephalitis
Low mortality

Question 19

Equine resevoir vs vector

Answer 19

Horses + birds = reservoir

Transmitted by mosquitoes

Question 20

Buzzword for Eastern vs Western

Answer 20

Eastern = USA swamps 
Western = USA irrigation sites

Question 21

What is the family and genome for La Crosse aka California viruses?

Answer 21

Bunya (Bring pol...)
-ssRNA - cytoplasm replication
*Brings own RNA pol*
Helical capsid
Enveloped

Question 22

California virus presentation

Answer 22

Kids: neuroinvasive disease
I.e. seizures
Likely to recover w/o long term complications but scary in the short term
Least severe of all the mosquito borne encephalitis

Question 23

How is California virus transmitted? Where?

Answer 23

Triseriatus mosquitoes
Live in hollowed out trees along forest edges
Midwest & south USA

Question 24

Rabies - genome + family

Answer 24

Rhabdo
- ss RNA
Helical capsid
Enveloped

Question 25

Rabies pathogenesis

Answer 25

Bite from rabid animal Into muscle cells - SLOW replication - months Eventually enters motor nerve Retrograde FAST replication - spreads throughout CNS Peripheral dissemination

Question 26

Once rabies gets to the CNS, what are the 2 types of damage that can occur - how does each determine symptomatic presentation?

Answer 26

``` 1. Encephalopathic Dysregulation of NT = excitatory state Hyperactivity/agitated before... 2. Paralytic Ascending flaccid paralysis Neuron necrosis = coma ```

Question 27

What might you see in muscle cells infected with rabies on histo?

Answer 27

Negri bodies = accumulation of M protein = matrix protein as virus replicates and buds out

Question 28

Immune response to rabies

Answer 28

Abs vs G protein = attachment to muscle cells | Too slow - don't kick in until in CNS

Question 29

What is the most common rabies host in the US vs worldwide?

Answer 29

US = feral cats World = dogs - Aka if someone in your clinic has rabies from a dog, they got it outside the US Always be worried about bats, raccoons, etx

Question 30

Symptoms of rabies

Answer 30

``` Numbness at bite site Diplopia N&V CN palsy Unsteady gait ```

Question 31

Rabies incubation

Answer 31

LONG b/c localized | 30-90 days

Question 32

What's a weird symptoms that is a clue for rabies?

Answer 32

Fear of water | Suggests in encephalopathic stage of acute neuro disease

Question 33

Test for rabies

Answer 33

CSR culture | DFA stain neck skin biopsy

Question 34

Treat rabies

Answer 34

Gotta do it in the WINDOW period - when still localized in skin 2 parts: + rabies Ig + vaccine - must give IM in DELTOID