neurological virus Flashcards
eastern equine encephalitis (EEE) family, genome, and virion
family: togaviridae
genome: + ssRNA
virion: enveloped
venezuela equine encephalitis (VEE) family, genome, and virion
family: togaviridae
genome: +ssRNA
virion: enveloped
west nile family, genome, virion
family: flaviviridae
genome: +ssRNA
virion: enveloped
rabies family, genome, virion
rabies
family: rhabdoviridae
genome: - ssRNA
virion: enveloped
what vectors do toga viruses and flaviviruses often use
arthropods
common arthropod vectors includes
mosquitos, cullseta, aedes, culex, and ticks
reservoirs for neuro viruses often include
birds and small mammals
togaviruses and flaviviruses often use vectors for transmission but what is required for transmission to actually occur
the virus must replicate in the vector
EEE and VEE virus Biology including family, genome, and vision
family: togaviridae
genome: +ssRNA
virion: enveloped
what important proteins do EEE and VEE use and what are their functions
E1 and E2: cell attachment and entry capsid protein (wrapped around genome) non structural proteins
where does replication of EEE and VEE occur
replication occurs in the cytoplasm
How EEE/VEE introduced and what does it do in the body
EEE/VEE introduced through bite of infected arthropod
infect locally or carried by langerheran cells to LN
replication and released into the blood stream
EEE and VEE rarely infect what in the body in about 5% of cases
EEE/VEE can infect organs such as the CNS and the method of crossing the blood brain barrier is unknown
Go through the process of bite, to incubation, to symptoms
a person is bite, virus incubates for 4- 10 days then causes a systemic disease of chills, fever, malaise, arthralgia, myalgia that last 1-2 weeks
EEE and VEE usually lasts about 1-2 weeks before recovery but in rare cases is can cause encephalitic disease which causes what kinds of symptoms
EEE and VEE encephalitic disease causes fever, headaches, irritability, restlessness, vomiting, diarrhea, convulsions, coma.
1/3 of encephalitic diseased die 2 to 10 days after onset,
those who recover from encephalitic disease of EEE and VEE usually experience what
long term sequelae of seizures, personality disorders, and paralysis
prevention and control of EEE and VEE
vaccine (TC-83 live, attenuated TC-84) provided to those at risk, only partially effective against inhalation dispersal of EEE and VEE. Vaccine causes virus symptoms
Supportive care is main treatment, prevention of mosquitos is key
Where in the US is EEE most prevalent
on the east coast south to texas
West nile virus biology including family, genome, vision
family: flaviviridae
genome: +ssRNA
virion: enveloped
West nile virus disease incubation time, symptoms and timeframe
incubation: 2 to 14 days. most persons have asymptomatic infections
illness: about 20% of infections duration of 3 to 6 days
west nile virus disease can change from a acute illness to a neuroinvasive disease in about 1 % of people what symptoms are involved with this neuroinvasive disease
neuroinvasive west nile disease causes aseptic meningitis, encephalitis, flaccid paralysis, altered mental state, tremors
50% of survivors have sequelae 12 months later
west nile virus prevention and control
no vaccine, no treatment just supportive care prevent by mosquito control and repellant
why is the west nile virus more widespread than EEE and VEE
west nile virus is widespread across the US bc its bird reservoir is a migratory bird
rabies virus biology including family, genome, and virion
rabies
family: rhabdoviridae
genome: -ssRNA
virion: enveloped
what proteins does rabies virus use
N- nucleoprotein P- phosphoprotein M- matrix G glycoprotein for attachment and entry L- polymerase
Rabies biology facts about replication, genome, and proteins
broad tropism
replicates in cytoplasm
genome order dictates abundance of transcripts and proteins
binding of N to RNA triggers genome replication
the beginning of rabies genome has ____ proteins and the end of the genome has ____ proteins
more
less
what do cellular receptors of rabies virus do
cellular receptors can facilitate entry into a variety of cells
rabies virus transmission and reservoirs
transmitted by bite of infected animal, reservoir of bats, skunks, raccoons, dogs
common in developing countries rare in US
rabies virus disease incubation and spread
rabies incubates for 1 to 3 months longer is possible
spread: replicates locally until it finds neurons, moves passively in axoplasm of peripheral nerves to spinal ganglia spinal cord, and brain
spreads back to periphery, highly innervated salivary glands and replicates
rabies virus symptoms and outcome
rabies symptoms: itching where bitten, fever, headache
hydrophobia, difficulty swallowing, foaming at mouth
cerebral dysfunction, anxiety, confusion delirium, hallucinations, insomnia
outcome: once symptoms occur almost always fatal
only 10 documented survivals, 2 having no history of previous prophylaxis
rabies virus and prevention and control
vaccine available, post exposure shots immediately after with 4 doses.
immunoglobin
control of rabies in animals
why does rabies virus infection require multiple doses
because the prophylaxis is not very immunogenic
