RNA - Rhabdoviridae

Question 1

Morphology of Rhabdoviridae

Answer 1

enveloped with spikes.

bullet shaped

Helically coiled cylindrical nucleocapsid

Question 2

what does the L protein do?

Answer 2

(1) L protein: Large protein, RNA-dependent RNA polymerase (transcriptase)

Question 3

what does the G protein do?

Answer 3

(2) G protein: Glycoprotein that forms the envelope spikes

Question 4

What does the N protein do?

Answer 4

(3) N protein: Nucleoprotein, associates with RNA to form the viral nucleocapsid

Question 5

What does the P protein do?

Answer 5

(4) P protein: Phosphoprotein that mediates binding of L protein to the nucleocapsid

Question 6

What does the M protein do?

Answer 6

(5) M protein: Matrix protein, associates with the viral nucleocapsid and lipid envelope

Question 7

T/F: Rhabdoviridae had 4 genera.

Answer 7

False. They have 6. We only care about 4

Question 8

How many genotypes are in Lyssaviruses? What’s the most important?

Answer 8

• 11
• Most important member of this genus: Rabies virus, genotype-1 Lyssavirus

Question 9

Who injected dried, potassium hydroxide treated, infected rabbit brain material in two boys bitten by rabid dogs and both of them recovered?

Answer 9

Louis Pasteur

Question 10

Etiology of Rabies?

Answer 10

Lyssavirus

Question 11

Which countries are in the no risk category for Rabies?

Answer 11

Japan, Singapore, New Zealand, Antarctica, and many Caribbean islands

Question 12

Which animals are highly susceptible to rabies?

Answer 12

Domestic cats and cattle

Question 13

which animals are moderately susceptible to rabies?

Answer 13

Dogs, sheep, goat, horses, primates, and humans

Question 14

How is rabies transmitted?

Answer 14

• Bite or scratch. its in the saliva or neurological tissues
• Aerosol has been documented
• Tranplants have been recorded in humans (liver, kidney, pancreas)

Question 15

T/F: Dogs are dead end hosts for Rabies

Answer 15

False. it is the main reservoir

Question 16

The urban cycle of rabies fominates where?

Answer 16

Africa, Asia, South and Central America

Question 17

The sylvatic cycleis dominant where?

Answer 17

Europe and North America

Question 18

What are the dead end hosts of Rabies?

Answer 18

cattle, sheep, horses, goats, and humans

Question 19

What is the most important wildlife reservoir of rabies?

Answer 19

Bats!

 In many bats, the infection is asymptomatic

 Rabid bats may develop paresis or paralysis, or may be disoriented, or may sometimes show aggression

Question 20

Insectivorus bats with rabies is reported where?

Answer 20

North America.

Question 21

Vampire bats with rabies are reported where?

Answer 21

Mexico, Central America, and parts of South America.

 In Latin America, about 250,000 to 500,000 cases of cattle rabies annually are attributed to vampire bats

Question 22

Fruit bats with rabies are reported where?

Answer 22

Australia

Question 23

Which wildlife animal account for most cases of cattle rabies?

Answer 23

Skunks

Question 24

Which animal has been most important in the perpetuation of wildlife rabies in the central regions of USA.

Answer 24

Skunks

Question 25

Which animal continues to be the most frequently reported rabid wildlife species?

Answer 25

Raccoons

Question 26

T/F: Red fox carries rabies

Answer 26

True

Question 27

Look at notes for Pathogenesis of Rabies.

Answer 27

Know ALL the THINGS!

Question 28

T/F: After intranasal exposure, the virus commonly enters the trigeminal nerves and ganglia in its course to the CNS.

Answer 28

False. This can happen but uncommon

Question 29

The virus reaches the limbic system where it replicates extensively, leading to what form of rabies?

Answer 29

the “furious” form of rabies.

Question 30

The virus spreads within the CNS continues, with replication in the neuro-cortex, resulting in what form of rabies?

Answer 30

the “dumb” or “paralytic” form of rabies.

Question 31

T/F: the rabies 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) in early infection. Extenisive replication leads to high concentration in saliva

Answer 31

False. In late infection

Question 32

T/F: ## Footnote Humoral and cell-mediated immune responses normally cannot be detected during the time the rabies virus moves from site of bite to the CNS.

Answer 32

True

Question 33

T/F: Neurons express MHC class I proteins.

Answer 33

False. Neurons do not express MHC class I proteins. Also, rabies infection is non-cytopathic in muscles and nerve cells. Therefore, very little antigen is released to stimulate host defense mechanisms.

Question 34

T/F: Antibodies against rabies virus appear in serum and later in cerebrospinal fluid (CSF) **after** neurological signs appear.

Answer 34

True

Question 35

What does the incubation period of rabies depend on?

Answer 35

* dose of inoculated virus * strain of virus * site of bite * degree of innervation.  Side note: Closer site of bite to brain, shorter the incubation period. Higher the degree of innervation at site of bite, shorter the incubation period.

Question 36

What are the clinical forms of rabies?

Answer 36

* Prodromal * Acute excitative (Furious form) * MAD DOG SYNDROME and HYDROPHOBIA * Paralytic/endstage (Dumb form * PARALYSIS See ppt for more details

Question 37

How do you diagnose Rabies?

Answer 37

**Direct FAT** to demonstrate rabies antigen in touch impressions of brain tissue. Negri bodies RT-PCR **intracerebral inoculation of weanling mice** - develop encephalitis within 14 days

Question 38

How do rabies free countries control rabies?

Answer 38

Rabies free countries: Quarantine involving segregation of dogs and cats in licensed premises for 6 months. ## Footnote

Question 39

How do endemic countries control rabies?

Answer 39

Endemic countries: Vaccination of dogs and cats; wildlife vaccination

Question 40

Recommendation after animal has been exposed to rabies?

Answer 40

* **Previously Unvaccinated**: Euthanize immediately, or quarantine in secure enclosure for 6 months; vaccinate 1 month before release. * **Vaccinated, but not current**: Evaluate case-on-case basis * **Vaccination, curren**t: Revaccinate immediately and keep under owner’s control for 45days

Question 41

What is used to control wild life rabies?

Answer 41

Bait vaccines

Question 42

Etiology of Vesicular Stomatitis?

Answer 42

Vesiculovirus The disease is caused by a group of antigenically related, but distinct viruses. No cross-protection among the different serotypes

Question 43

What are the most important types of vesiculovirus?

Answer 43

**Indiana serotype** [subtypes: Fort Lupton, Alagaos, and Coccal **New Jersey serotype**: The New Jersey serotype is more virulent and has the widest distribution.

Question 44

Host of vesiculovirus

Answer 44

* Mostly cattle, pigs, and horses in the Americas. Occasionally sheep and goats * Influenza-like disease in Humans

Question 45

Where does Vesiculo Stomatitis often occur?

Answer 45

Americas and Caribbean

Question 46

How is vesiculo stomatitis transmitted and routes of infection?

Answer 46

breaks in the mucosa or skin ## Footnote Routes: Contact with contaminated milking machines [teat and udder lesions] Chewing or ingestion of contaminated fomites [mouth lesions] Arthropods

Question 47

T/F: biological transmission by arthropods is believed to be more significant than mechanical transmission

Answer 47

False

Question 48

Disease in Cattle? * Excess salivation and fever often are the first signs of infection in cattle and horses * Vesicles that develop on the tongue, the oral mucosa, teats, and coronary bands of cattle rapidly rupture to leave extensive ulcers that quickly become secondarily infected. * These lesions may cause profuse salivation and anorexia, lameness, and rejection of suckling calves.

Answer 48

vesicular stomatitis

Question 49

What is most pronounced clinical sign of vesicular stomatitis in horses?

Answer 49

In horses, tongue lesions ## Footnote

Question 50

What is most pronounced clinical sign of vesicular stomatitis in swine?

Answer 50

vesicular lesions are most common on the snout and coronary bands. lameness too

Question 51

T/F: In humans, vesicular stomatitis is a self-limiting influenza-like disease (headache, fever, myalgia, and weakness) lasting for 3-5 days.

Answer 51

True

Question 52

T/F: ## Footnote  Vesicular stomatitis is clinically distinguishable from other vesicular diseases of cattle and pigs, including foot-and-mouth disease (cattle & pigs), Swine vesicular disease (SVD), & and vesicular exanthema of swine .

Answer 52

False

Question 53

How do you diagnose vesicular stomatitis in horses?

Answer 53

Vesicular lesions in horses are characteristic only of vesicular stomatitis

Question 54

T/F: Vesicular stomatitis is not reportable

Answer 54

False

Question 55

Etiology of Bovine Ephemeral Fever (BEF)

Answer 55

bovine ephemerovirus

Question 56

T/F: BEF has been reported in North America

Answer 56

false

Question 57

Transmission of BEF?

Answer 57

Arthropod-borne Believed to include Culicoides spp. and possibly mosquitoes

Question 58

Which disease is associated wth the buffy coat fraction of blood?

Answer 58

Bovine Ephemeral Fever

Question 59

What is left shift? And in which disease?

Answer 59

early neutrophilia with abnormal level of immature neutrophils in the circulation BEF

Question 60

T/F: In BEF there is an decrease in plasma fibrinogen and a significant increase in plasma calcium.

Answer 60

False. There is an increase in plasma fibrinogen and a significant decrease in plasma calcium.

Question 61

Disease in Cattle? Fever, which is often biphasic, triphasic or polyphasic. Inappetence, excessive salivation, serous nasal discharge, drooling, increased heart rate, dyspnea, stiffness and lameness, and a sudden decrease in milk yield.

Answer 61

Bovine Ephemeral Fever

Question 62

How long does it take to recover from BEF?

Answer 62

* Recovery is dramatic and usually complete in 3 days [2-5 days] * Some animals may become recumbent and paralyzed for 8 hr to \>1 wk.

Question 63

how do you diagnose BEF?

Answer 63

inoculation of infected buffy coat cells into cell cultures derived from *Aedes albopictus*, or IC inoculation of sucking mice.