Rhabdoviridae Flashcards
what is unique about rhabdoviridae morphology? very characteristic
enveloped and BULLET SHAPED
what are the 5 important proteins encoded by rhabdoviridae
1 - L. Large protein, RNA dependent RNApol
2- G. Glycoprotein that forms the envelope spikes
3- N. Nucleoprotein, associates with RNA to form nucleocapsid
4- P. Phosphoprotein, mediates binding of L protein to the nucleocapsid
5- M. Matrix protein, associates with the viral nucleocapsid and lipid envelope.
t/f - rhabdoviridae have single stranded, negative sense RNA
true
rhabdoviridae replicate in the ______ and maturation is done by budding through the _______
cytoplasm
plasma membrane
t/f - rhabdoviruses can cause rapid cytopathology OR be non-cytopathogenic.
true.
i.e. vesicular stomatitis virus, cytopathic.
street rabies virus strains, non-cytopathogenic.
what are the three major diseases caused by rhabdoviridae, and which genera are they?
- bovine ephemeral fever virus (Ephemerovirus)
- rabies virus (Lyssavirus)
- vesicular stomatitis virus (Vesiculovirus)
what is the particular etiology of rabies?
Genotype-1 Lyssavirus
what are some low risk countries for rabies?
japan, singapore, NZ, antarctica, and lots of caribbean islands
what are the 8 species that you need to know for contracting rabies?
High risk: cats and cattle
Moderate risk: dogs, sheep, goats, horses, primates, humans
main mode of transmission of rabies?
bite or scratch of animal with virus in saliva
what are some minor modes of transmission for rabies?
Less often, an animal or person is infected by contact with infectious saliva or neurological tissues, through mucous membranes or breaks in the skin.
Aerosol transmission has been documented in special circumstances, such as in laboratories and bat caves
A few human cases have been reported after transplantation of organs, particularly corneas but also pancreas, kidneys and liver
Though most animals are susceptible to rabies infection, many are ‘dead end’ hosts who will be unlikely to transmit the infection. Such ‘dead end’ hosts include ______________________
humans and most herbivores: cattle, sheep, goats and horses
why are bats significant in rabies?
Important Wildlife Reservoirs: Bats
Many species of bats harbor different variants of rabies virus.
In many bats, the infection is asymptomatic
Rabid bats may develop paresis or paralysis, or may be disoriented, or may sometimes show aggression
there are three important kinds of bats for lyssavirus. what are they, and where are they?
1) Insectivorous bats - north america
2) vampire bats - mexico, central, south america
3) fruit bats - australia
t/f - skunks are a reservoir for rabies
true:
Skunks have been most important in the perpetuation of wildlife rabies in the central regions of USA.
They account for most cases of cattle rabies
t/f raccoons and red foxes are reservoirs for rabies
true
raccoon is most frequently reported rabid wildlife species
describe pathogenesis of rabies virus, with regards to entry of the virus
- After Intramuscular inoculation, virus may
enter peripheral nerves directly, or replicate locally in non-nervous tissue until they reach sufficient concentration to reach motor or sensory nerve endings in the muscle or skin. - the G or glycoprotein of the virus bind to axon terminals of peripheral nerve fibers through lipoprotein receptors, including those for acetylcholine, facilitating its entry into nerve endings.
- The greater the degree of innervation at the site of bite, the shorter the incubation period.
- Location of Injury: Bites to face have the greatest risk
T/F - although uncommon, after intranasal exposure, the rabies virus may enter the trigeminal nerves and ganglia in its course to the CNS
true
describe pathogenesis of rabiesvirus with regards to the spread into the CNS, and excretion.
The second phase of infection begins when the virus progresses centripetally to the CNS via the axoplasm of the peripheral and central nerves.
The virus reaches the limbic system where it replicates extensively, leading to the “furious” form of rabies.
Spread within the CNS continues, with replication in the neuro-cortex, resulting in the “dumb” or “paralytic” form of rabies
Late in infection, the virus moves centrifugally from the CNS down the peripheral nerves to a variety of organs including the adrenal cortex, pancreas and the salivary glands (via cranial nerves).
Extensive replication of virus in salivary glands results in high concentration of virus in saliva
what are the epidemiological cycles of rabies?
one sylvatic and one urban
urban- dogs are the main reservoir; predominant in africa, asia, central/south america
sylvatic- predominant in europe and north america; also present simultaneously with the urban cycle in some parts of the world.
what are the characteristic macroscopic lesions of animals who’ve died from rabies?
psyche! there are none
The brains of animals with rabies exhibit variable inflammation and often only modest histological evidence of neuronal injury.
how do you detect the immune response in an animal as the rabies virus moves from the bite into the CNS?
PSYCHE
you don’t bruh. usually no CMIresponse or humoral during that time period.
