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):


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


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

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


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%



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


MERS = Middle Eastern Respiratory Syndrome

Emerging infection (Saudi Arabia 2012)

Viral respiratory illness - transmitted via respiratory droplets

Animal source - camels?


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