Neurological Viruses Flashcards
what types of virus classes are transmitted via arthropod transmission?
selected togaviruses and flaviviruses
what are some common arthropod vectors?
- mosquitos: culiseta, aedes, culex
- ticks
what are some common arthropod reservoirs?
birds and small mammals
T/F: transmission requires replication in the vector
T
geographic location determined by ______ and _______ habitat
vector, reservoir
describe the eastern equine encephalitis (EEE) and venezuelan equine encephalitis (VEE)
- togaviridae
- genome: (+)ssRNA
- virion: enveloped
- proteins:
- E1&E2: cell attachment & entry
- capsid protein
- carious non-structural proteins
** non-structural proteins important at first and structural proteins important later
where is replication at for EEE and VEE?
- no nuclear access
- goes thru ER (picks up envelope material)
- RNA packaging scheme then buds off surface
how do EEE and VEE enter a cell?
- virus introduced through the bite of an infected arthropod
- infect cells locally and/or carried by Langerhans cells to LN
- replication and release into the blood stream
- infection in other target organs such as the CNS
- method of crossing blood-brain barrier is unknown
what is the EEE incubation period?
4-10 days
what are the symptoms of the EEE systemic disease?
chills, fever, malaise, arthralgia, myalgia
lasting 1-2 weeks full recovery
what are the symptoms for the EEE encephalitis disease?
fever, headache, irritability, restlessness,vomiting, diarrhea, convulsions, and coma
do people die from the encephalitis infection of EEE and if so how prevalent is mortality?
1/3 encephalitic cases die from the disease 2-10 days after onset
T/F: those who recover from the encephalitis infection of EEE can have long term sequelae
T: seizures, personality disorders, paralysis
is there a vaccine for EEE and VEE? describe
- a single vaccine is available (TC-83)
- live attenuated (TC-83)
- inactivated (C-84)
- only provided to at risk military personnel and researchers
- partially effective against inhalation challenge in primates
is there any treatment for EEE and VEE?
no treatment just supportive care
what types of prevention are there for EEE and VEE?
- mosquito control strategies
- mosquito repellant
where in the US is the most prevalence for EEE?
east coast
what is the incubation period for the west nile virus?
2-14 days and most persons (80%) have asymptomatic infections
illness from west nile virus occurs in ~20% of cases, what are the symptoms?
fever, headache, fatigue for 3-6 days
can west nile virus ever become neuroinvasive?
yes, <1%
- aseptic meningitis, encephalitis, flaccid paralysis, altered mental state, tremors
- 50% of survivors have sequelae 12 mos later
is there a vaccine for west nile virus?
no
is there treatment for west nile virus?
no
what can be done to prevent west nile virus?
- mosquito control strategies
- mosquito repellant
where is west nile the most prevalent in the US?
across entire US because range for birds (vector) is wider than mosquitos
what type of virus is rabies virus?
- rhabdoviridae
- genome: (-)ssRNA
- virion: enveloped
- proteins:
- nucleoprotein
- phosphoprotein
- matrix
- glycoprotein (attachment & entry)
- polymerase
does rabies have broad tropism?
yes, the glycoproteins on surface can bind many cell receptors so can infect many
where does rabies replicate inside the cell?
cytoplasm
T/F: the order in which the rabies virus genome is composed dictates the abundance of transcripts and proteins
T
Binding of ________ to RNA triggers rabies virus genome replication
nucleoprotein: makes (+) strand–>progeny genome production
how is rabies virus transmitted?
bite of infected animal
15% of bites cause disease
60% if on face or head
what is the reservoir for rabies virus?
bats, skunks, raccoons, dogs in developing countries
what is the incubation period for rabies virus?
1-3 mos.
longer is possible, though rare
depends on location of bite
how is rabies spread?
- replicates locally until it finds neurons
- at site of bite, moves up neurons to brain and spreads back to peripheral nervous system
- goes to salivary glands and replicates
what are the symptoms of rabies virus?
- prickling or itching where bitten, fever, headache
- hydrophobia: difficulty swallowing, even saliva, leads to “foaming at the mouth”
- cerebral dysfunction, anxiety, confusion, delirium, hallucinations, and insomnia
what is the outcome of rabies virus?
- once symptoms appear, disease is nearly always fatal
- only 10 documented survivals, only 2 of those had no history of previous prophylaxis
is there a rabies vaccine?
yes
is post-exposure prophylaxis possible for rabies?
- should be administered immediately for bites that break skin
- 4 doses: immediate, 3, 7, 14 days
- should also receive immunoglobulins (RIG)
does vaccination of dogs and wildlife help spread?
of course
