Neurological Viruses Flashcards
West Nile virus is the same famile as what virus, so it has the sam biology
the same family as HCV (Flavivridae)
Selected togaviruses and flaviviruses are transmitted how
through a vector
what kind of host are humans for west Nile virus
dead end host (normally between birds and mosquitos)
Common vectors for arthropod transmission
Mosquitoes: Culiseta, Aedes, Culex
Ticks
Reservoirs for Arthropod transmission
birds
Small Mammals
what is neccessary in the vector for transmission
replication in the vector
where does a virus replicate in a mosquito
in the stomach
Geographic location of Arthropod transmission determined by
vector and reservoir habitat
what type of virus is EEE and VEE Virus
Togaviridae
Genome of EEE and VEE Virus
(+)ssRNA
Virion and EEE and VEE Virus
enveloped
Proteins of EEE and VEE Virus
E1 and E2: cell attachment and Entry
Capside Protein
Various non-structural proteins
proteases: chop up polypeptides into fucntional proteins used in the replication cycle and creating new virus particales themselves
how do EEE and VEE Virus get into the cell
Receptor mediated endocytosis
membrane fusion dumps nucleocapside into the cytoplasm
how does EEE and VEE Virus leave cell
budding
where does EEE and VEE Virus do replication
in the cytoplasm
How does one get the EEE and VEE Virus
Introduced through the bite of an infected arthropod
Travel of EEE and VEE Virus in the body
infect cells locally and/or carried by Langerhand cells to lymph nodes
Replicated and then released into the blood stream
Infect target organs such as CNS
how does EEE and VEE Virus cross the Blood-brain barrier
unknown
Incubation period of EEV virus
4-10 day
Systemic disease by EEv virus
Chills, fever, Malaise, arthralgia, myalgia
how long does systemic disease by EEV last
1-2 weks
Encephalitic disease by EEV Virus
Fever, Headache, irritability, restlessness, vomiting, diarrhea, Convulsions, and coma
how many people die of ENcephalitic disease by EEV
1/3 of encephalitic cases fie 2-10 days after onset
what happens to people that do not die of EEV
have long term sequelae (Seizures, personality disorders, paralysis)
Initiatl response to EEV virus
Innate immunity by interferon
then antibodys and inflammation: T cells, B cells, Monocytes
prevention of EEE and VEE
Vaccine
No treatment
Mosuito control and repellant
Vaccine for EEE and VEEE
Live attenuated: TC:83
Inactivated: C-84
who gets the EEE and VEE Vacine
provided to at risk military personnel and reasearch
-lots of bad side effects after getting the vaccine
also veterinary vaccines exist
effectiveness of EEE and VEE against inhalation challenge in primates
partially effective
where do we ind EEE in the US
along the east coast, or in swamps near the south.
can go as far test as wisconsin or texas
Incubation time of west nile
2-14 days
what do most infections of west nile look like
asymptomatic infections (80% of infected)
IF west nile virus causes illeness(20%), what are the symptoms
Fever, headache, and fatigue for 3-6 days
if west nile virus becomes neuroinvasive (<1%), what are the symptoms
Aseptic Meningitis, Encephalitis, flaccid paralysis, altered mental state, tremors
if you survive west nile virus neuroinvasion, what happens
50% of survivors have sequelae 12 months later
Prevention of west nile
NO approved vaccine
no treatment (only supportive care)
mosquito control and repellant
the main transmitters of West Nile
Culex sp. Mosquitoes
where is WEst Nile virus active in the US
almost all over the US active in humans
why is the range for EEE and WNV different
West nile virus mosquitoes live everyhwere, while EEE mosquitoes only live in a small area
what type of virus is Rabies Virus
RHabdoviridae
Genome for Rabies VIrus Biology
(-)ssRNA
linear
Virion of Rabies virus
Enveloped
Proteins of Rabies Virus
N - Nucleoprotein P - phophoprotein M - matrix G - glycoprotein (attachment and entry) L - polymerase
what must a (-)ssRNA need to complete infection on its own
RNA dependent RNA polymerase
which proteins get made the most in RAbies Virus
the first genes, becasue theres a change RNA Polyerase might fall off and stop making later down proteins
Tropism of Rabies Virus
Broad
Where does RAbies Virus Replicate
In the Cytoplasm only
what dictates abundance of transcripts and proteins in Rabies virus
Genome order
what triggers genome replication of Rabies Virus
Binding of N to RNA
what deffective particles does Rabies virus produce
defective interfering particles- sloppy
how does Rabies VIrus get into the cell
Absorption into cellular membrane
Fuses with endosome
the uncoats and genome comes out
how does rabies Virus leave
Budding
How is Rabies Virus transmitted
By infected animal
(15% of bites cuase diase)
(60% if on face or head)
Reservoir for Rabies VIrus
Bats, skunks, racoons…
what is the common source of human rabies death
Common in dogs in developing countries
commonness of RAbies Virus in US
only a few cases
Incubation period of Rabies vIrus
1-3 months (can be longer) (depends on location of bite)
How does RAbies Virus Spread
Replicates locally until it finds neurons
Moves passively in axoplasm of peripheral nerves to spinal gnaglia, spinal cord, and brain
Spreads back to periphery, highly innervated salivary glands and replicates
Symptomes of RAbies virus
Prickling or itching where bitten, fever, headache
Hydrophobia
Cerebral dysfunction, anxiety, confusion, delirium, hallucinations, and insomnia
Hydrophobia
Difficulty swallowing, even saliva leads to “foaming at the mouth”
Outcome of Rabies VIrus
Disease nearly always fatal once symptoms appear
who has survied Rabies
10 documented surfivials, only 2 of those had no history or previous prophylaxis
Prevention of RAbies
Vaccine
Post-exposure prophylaxis
Control of Rabies
Vaccination of dogs and domestic animals is essential
wild life vaccine using baits with oral vaccine
when should post-exposure prophylaxis be given for rabies
Administered immediately for bites that break the skin 4 doses( immediate, 3, 7, 14 days) Also receive immunoglobulin (RIG)
