Ch. 16 - Viral Infections Of The Nervous System Flashcards Preview

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Flashcards in Ch. 16 - Viral Infections Of The Nervous System Deck (6):
1

Rabies

Bullet shaped morphology

Most deadly virus --> once symptoms arise, almost always fatal

Enter through skin wound with contaminated bodily fluid of infected animal ( warm-blooded animal, saliva)

Incubation period: 6 days - 1 year
-depending on the location of entry and amount of virus entering the body --> the closer the bite is to a nerve/spinal cord, the shorter the incubation period

Symptoms: fever, headache, increased muscle tension

Become alert, aggressive, followed by paralysis and brain degeneration = Encephalitis

Hydrophobia - brain inflammation and inability to swallow - violent reaction to water

Death from respiratory paralysis

Post exposure immunization of rabies IgG

2

Polio (poliomyelitis)

Infect grey matter of the spinal cord and brain (nervous tissue)

Enter through contaminated food or water

Replicate in gut, tonsils, lymph nodes

Pass blood-brain barrier to meninges -->paralysis of limbs and trunk
(Paralytic poliomyelitis)

Postpolio syndrome - individuals who have had the disease before; reactivated virus or autoimmune reaction (attack motor neurons as if foreign objects); muscle weakness, atrophy

Vaccine:
1. Salk - dead, inactivated virus; injection; 4 doses; only pieces of virus (cannot replicate)

2. Savin - live, attenuated virus; oral; not given in US; live virus (can replicate)

Not fully eradicated - new vaccine-derived virus --> emergence of new strains; by 2000 99% fewer cases

3

Viral Hemorrhagic Fever (VHF) Viruses

Ex: Yellow Fever, Dengue Fever, Lassa, Ebola, Marbug

RNA viruses

Animal insect/host = natural reservoir
Eg (Ebola reservoir = fruit bats)

Damage endothelial cells --> massive internal bleeding and hemorrhaging

Humans infected when come into contact with infected host; can infect one another when in contact with blood or bodily secretions (or contaminated objects)

No cure or drug treatments (exception - Lassa Fever: Ribavirin)

Mortality rate: 50-90%

4

Chikungunya

Viral Hemorrhagic Fever (2006)

= to walk bent over (reference to sever joint pain)

Symptoms: fever, headache, vomiting, severe long lasting joint pain

Vector: mosquito --> transmit to other humans
Jet travel: endemic to areas around Indian Ocean -and- Southern Europe

Spread through blood to liver, muscle, brain, lymphatic tissue, and joints

No specific antiviral treatment --> all cases resolved

5

MERS = Middle Eastern Respiratory Syndrome

Emerging infection (Saudi Arabia 2012)

Viral respiratory illness - transmitted via respiratory droplets

Animal source - camels?

6

West Nile

Primary transmission: crows --> mosquito

Incidental Transmission: mosquito --> horse, human (dead end host)

Most: asymptomatic - fever, aches, fatigue

Few: develop encephalitis, meningitis --> permanent neurological damage or death (elderly, immunocompromised)

No vaccine or treatment