rhabdoviridae

Question 1

rhabdoviridae morphology

Answer 1

visions enveloped with large spikes bullet shaped, helically coiled cylindrical nucleocapsid

Question 2

rhabdoviridae general proteins

Answer 2

L protein, G protein, N protein, P protein, M protein, single molecule linear - sense ssRNA, cytoplasmic replication, mature through budding of plasma membrane, can be cytopathoic or noncytopathic forms

Question 3

L protein Large protein

Answer 3

RNA dependent RNA polymerase (transcriptase)

Question 4

G protein Glycoprotein

Answer 4

envelope spikes

Question 5

N protein Nucleoprotein

Answer 5

associates with RNA to form the viral nucleocapsid

Question 6

P protein Phosphoprotein

Answer 6

mediates binding of L to nucleocapsid

Question 7

M protein Matrix protein

Answer 7

associates with the viral nucleocapsid and lipid envelope

Question 8

rhabdo classification

Answer 8

genus: ephemerovirus-bovine ephemeral fever
genus: vesiculovirus-vesicular stomatitis
genus: lyssavirus-rabies

Question 9

lyssavirus- rabies

Answer 9

caused by genotype 1, carribean islands, japan, singapore, new zealand, low risk, but worldwide distribution

Question 10

host species for rabies

Answer 10

high risk-cats, cattle
moderate risk-dogs, sheep, goats, horses, monkeys, humans
all warm blooded susceptible

Question 11

rabies transmission

Answer 11

bite or scratch, virus in saliva less often, sometime aerosol, some even from transplants of organs

Question 12

epidemiology of rabies

Answer 12

sylvatic cycle with vampire bats in central and south america
foxes in europe, coyotes in NA, jackals africa

this cycle most common in NA

Question 13

urban cycle of rabies

Answer 13

dogs main reservoir africa asia south and central america; many herbivores are dead end hosts -cattle sheep goats and horses

Question 14

rabies transmission involving bats

Answer 14

many specie harbor it, asymptomatic usually, can develop paresis or paralysis, may sometimes show aggression, insectivore bats common in NA,
vampire bats in mexico and central america, fruit bats in australia

Question 15

rabies transmission involving skunks

Answer 15

most important in USA, most cases of cattle rabies, along with raccoons on the east coast

Question 16

rabies path

Answer 16

1. intramuscular inoculation, can enter peripheral nerves or in non-nervous tissue until reach high concentration
2. the G protein binds to axons terminals of peripheral nerve fibers through lipoprotein receptors like Ach and enter nerves
3. shorter incubation for more highly innervated regions
   4 bites to face have greatest risk

Question 17

uncommon routes rabies

Answer 17

intranasal-trigeminal nerves

Question 18

spread of rabies

Answer 18

furious form replicates in limbic system, dumb or paralytic form is CNS spread, can move to salivary glands (hypersalivation)

Question 19

pathology and immunology

Answer 19

inflamed brain, functional lesions over structural.
both hum moral and cell mediated immunity undetected during spread of virus, no MHC proteins, noncytopathic infection, little antigen released but CSF has small amount of antibodies

Question 20

incubation of rabies

Answer 20

depends on strain, site of bite, and degree of innervation, (closer to the brain is shorter), phases include prodromal, acute excitative (furious), and paralytic/endstage ( dumb)
**survival is rare

Question 21

prodromal period

Answer 21

shedding of virus and change in temperature

Question 22

furious form

Answer 22

mad dog syndrome, animal nervous, irritable, aggressive movements, posture change, dilated pupils, lose fear of everything, develop hydrophobia
more common in dogs and cats

Question 23

paralytic form

Answer 23

encephalitis progresses, fury leads to paralysis and ataxia, seizures, death within 2-14 days

Question 24

characteristic of bovine rabies

Answer 24

bellowing tail (elevated), salivation

Question 25

characteristic of equine rabies

Answer 25

dysphagia and salivation, posterior paralysis

Question 26

canine rabies furious form

Answer 26

growling

Question 27

canine paralytic phase

Answer 27

ptyalism, depression, paralysis, sternal recumbency with torticollis

Question 28

diagnosis of rabies

Answer 28

direct FAT to look for rabies antigen, recommended by WHO, look for negri bodies in cytology (only 75% show inclusions), RT-PCR, virus isolation in mice intracerebral inncoluation

Question 29

Direct fluorescent antibody test

Answer 29

negative-shows no fluorescence

positive-shows fluorescence

Question 30

rabies control

Answer 30

quarantine in rabies free countries for 6 months, in endemic countries-vaccinate dogs and cats.
preexposure- vaccinate at 3mo and once a year after
postexposure-revaccinate immediately and keep under owner’s control for 45 days
wildlife use bait vaccine*

Question 31

vesicular stomatitis (VS)

Answer 31

caused by group of anti genetically related but distinct viruses
host-cattle pigs and horses, sometimes humans and sheep and goats
serotypes-indiana and new jersey (most virulent)

Question 32

VS distribution

Answer 32

occurs primarily in the Americas and certain areas of the Carribbean

Question 33

VS transmission

Answer 33

enters through breaks in the skin, contaminated milking machine, ingestion of fomites, arthropods (black flies, sand flies, leaf hoppers)

Question 34

VS Path

Answer 34

enters through broken mucosa/ski, common in mucous membrane of the oral cavity and the skin, fluid filled vesicles form, extensive ulceration, entire epithelium of the tongue or teat sloughed, does not usually become systemic and viremic

Question 35

VS clinical signs

Answer 35

excessive salivation, fever, lameness, vesicles on tongue, ulcers, anorexia, more vesicular lesions in swine, humans have self limiting influenza like symptoms 3-5 days

Question 36

VS in cows

Answer 36

ruptured tongue vesicles, almost complete detachment of epithelial surface

Question 37

VS Dx

Answer 37

indistinguishable clinically from other vesicular diseases like foot and mouth, yet horses have only one vesicular Dx (VS)
VS is reportable**

Question 38

Bovine Ephemeral fever

Answer 38

genus: Ephemerovirus
host-water buffalo, cattle
never reported in NA
arthropod borne Cullicoides and mosquitos

Question 39

Bovine Ephemeral virus path

Answer 39

3 day sickness, poorly understood, virus in buffy coat of blood, early neutrophilia with high level of immature neutrophils (left shift), there is an increase in plasma fibrinogen and a significant decrease in plasma calcium

Question 40

Bovine Ephemeral Virus clinical features

Answer 40

polyerositis affecting joints, pleural and peritoneal surfaces, influx of neutrophils
fever, salivation, nasal discharge, lameness, may lay recumbent

Question 41

bovine ephemeral virus Dx

Answer 41

isolation of virus is difficult, can be attempted by inoculation of infected buffy coat cells into culture from A. albopictus