Rhabdoviridae Flashcards
Rhabdoviridae: morphology
Enveloped with large spikes, bullet-shaped, helically coiled cylindrical nucleocapsid
Rhabdovirus RNA encodes 5 important proteins
L (Large): RNA-dept RNA polymerase (transcriptase)
G(Glycoprotein): forms envelope spikes
N(Nuceloprotein): RNA to form viral nucleocapsid
P(Phosphoprotein): binds L protein to nucleocapsid
M(Matrix): asso. viral nucleocapsid and lipid envelope
Rhabdovirus genome
single molecule linear, neg-sense, ssRNA
Rhabdovirus replication takes place in ____, maturation happens by ___
the cytoplasm
by budding through the plasma membrane
Lyssavirus is known to cause
Rabies (genotype-1 Lyssavirus)
Rabies: transmission
Mostly by bite or scratch of infected animal via saliva
through mucous membranes or wounds, aerosol, and transplanted organs is possible
Rabies main host reservoir in urban cycles are
Dogs
Rabies often infect “dead-end” hosts which include
Humans and most herbivores
Rabies main host reservoir for sylvatic cycle is
Bats
also shunks for U.S. (raccoons, red fox)
Rabies CS in bats
Mostly asymptomatic
may develop paresis/paralysis, disoriented, aggression
Rabies viruses spreads in the body via
Nerves
G proteins binds to axon terminals
Rabies: Bites to the ___ (location on body) have the greatest risk
The face,
greater degree of innervation = shorter incubation
Rabies: uncommon routes of entry involve the __ (location) traveling by __ (nerve)
Intranasal exposure
Trigeminal nerve/ganglia
When rabies reaches the brain if it replicates in the ___ it leads to the ___ form, However, if it reaches the ___ it develops the ___ form
Limbic system, Furious form
neuro-cortex, dumb form
High concentration of rabies virus is contained in the __ (organ)
Salivary glands
T or F
There are macroscopic lesion of rabies infected animals
False
Histological evidence is seen
T or F
Little immunological response is seen in rabies infection
True
Very little antigen is released
Rabies: 3 clinical phases of infection
Prodromal
Acute excitative (furious)
Paralytic/End stage (dumb)
Rabies: prodromal period
Virus shedding and temperament change before CS are seen
Rabies: Furious form CS
Excitment/aggression, Disinhibiton
Hydrophobia (pharyngeal paralysis)
excessive salivation, extreme response to light and sound, hyperesthesia
Rabies: Dumb form CS
encephalitis, paralysis, ataxia, muscle weakness
convulsive seizures, coma, resp. arrest
Death
Rabies: diagnosis
Direct FAT- rabies antigens in brain
Negri bodies, RT-PCR, Intracerebral inoculation of weanling mice
Rabies: Control
Quarantine, vaccine
little treatment possible
Vesiculovirus causes
Vesicular Stomatitis
Two important serotypes of vesiculovirus
Indiana serotype
New Jersey serotype- more virulent, widespread
VS: transmission
through breaks in mucosa or skin
Arthropods
VS: pathogenesis
localized ulceration that can lead to epithelium being slough
VS: CS
ulcerated lesions on tongue and coronary band, excessive salivation, fever, anorexia
VS: first sign of infection in cattle and horses
Excessive salivation
VS: first sign in pigs
lameness
VS: diagnosis
Virus isolation, serum samples, CFT, VN
RT-PCR
Vesicular stomatitis is indistinguishable from other vesicular diseases, except in __(animal)
Horses
lesions characteristics of VS
VS: control
Reportable disese
quarantine areas, pest control, vaccines (with some success)
Ephemerovirus causes
Bovine ephemeral fever
3-day sickness
BEF: hosts
cattle and water buffalo
BEF: transmission
Arthropod borne
BEF: is asso. with ___ of blood
Buffy coat
BEF: CS
polyseroitis of joints, pleural, and peritoneal surfaces
High neutrophil in effusion fluids
fever, excess salivation, serous nasal discharge, dyspnea, stiffness, lameness
BEF: diagnosis
virus isolation (difficult), IC inoculation of sucking mice
BEF: control
attenuated virus vaccine
vector control
