Viral Zooneses I Flashcards Preview

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Flashcards in Viral Zooneses I Deck (51)
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1
Q

RABIES taxonomy

A

Family: Rhabdoviridae
Order: Mononegaviraes
Genus: Lyssavirus

2
Q

The genome of rabies virus

A

Linear (-) non segmented ssRNA, encodes 5 proteins (GLMNP)

3
Q

Viral particle of rabies virus

A

Bullet-shaped

Helical nucleocapsid

4
Q

Antigenic properties of rabies

A
Purified spikes (elicits antibodies)
Antiserum against purified nucleocapisd (immunofluirescence)
5
Q

How can you control rabies virus in the lab?

A
CO2
Trypsin 
Lipid solvents (0.1% sodium deoxycholate and ether)
Heat (50C for 1 hr)
UV rad or sunlight
6
Q

T or F: all warm-blooded animals are susceptible to rabies

A

True

7
Q

Natural reservoir of rabies

A

Bats and raccoons

8
Q

T or F: the rabies virus can only be found in the blood

A

False, it is widely disseminated. Found in Nervous system, saliva, lymph, blood, urine, and milk

9
Q

T or F: the bite of a rabid animal gives you a 20x greater chance of acquiring rabies than scratches

A

F 50x

10
Q

Human-human transmission of rabies t or f

A

??? Not yet confirmed

11
Q

How does rabies virus enter the body?

A

Adsorption

12
Q

This step of the rabiesviral replication comes after uncoating wherein mRNAs are syntheisized and is important in order to replicate inside cell

A

Transcription

13
Q

This step of the rabies viral replication process involves synth of 5 stuc proteins

A

Translation

14
Q

G-protein glycosylation in rabies

A

Processing step (after translation)

15
Q

How does rabies exit?

A

Budding

16
Q

Preferred site of rabies virus in the CNS

A

Brain stem and medulla

17
Q

Responsible for rabies viral replication in CNS

A

Endoneurium of schwann cells and associated spaces in sensory nerves

**reason why infected dog brains are examined

18
Q

When is saliva infectious in rabies

A

Two weeks before appearance of signs

19
Q

Other sites where rabies can replicate, produce cellular infiltrates and cause necrosis

A

Salivary glands and cornea

20
Q

Effects of rabies on the body

A

Hyperemia
Nerve cell destruction in midbrain, basal ganglia, cortex, pons and especially the medulla
Degeneration of axons and myelin sheaths
Demyelinization in white matter
Posterior horns of spinal cord: neuronophagia and Cellular Infiltrates: mononuclear, perineural, perivascular

21
Q

IP in dogs rabies

A

3-8 weeks, can be 10 days

22
Q

Rabies IP in humans

A

30-90 days

*shorter in children than adults

23
Q

Clinical stages of rabies virus in dogs

A

Prodromal

Excitative Paralytic

24
Q

This stage in dogs is characterized by fever and sudden change in behavior

A

Prodromal

25
Q

This stage in dogs is the most dangerous. Marked by irritability, restlessness, nervousness, exaggeration of response to light and sound, convulsive seizures, difficulty swallowing

A

Excitative

26
Q

T or F: All rabid dogs undergo excitative phase

A

False, can be skipped

27
Q

This stage in humans is marked by non-specific symptoms, pain or paresthesia in the inoculation site and involvement of symptoms in respiratory, GI, and CNS

A

Prodromal phase

**other symptoms
Agitation  Photophobia  Priapism (persistent & painful penile erection)  Increased libido  Depression  Insomnia  Nightmares  Encephalitis  Brain conditions  Psychiatric disturbances

28
Q

Begins with signs of CNS dysfunction in humans

A

Acute neurologic period

29
Q

Form of acute neurologic period characterized by hyperactivity, hydrophobia and aerophobia

A

Furious (classic or encephalitis)

30
Q

This form of acute neuro period in humans is marked by paralysis

A

Dumb rabies

31
Q

T or F: microscopic examination of rabies is done through light microscopy

A

False, immunofluorescence of infected using anti-rabies hamster serum

32
Q

Usual specimen if rabies virus

A

Cornea and brain

33
Q

Definitve diagnosis of rabies in microscopy

A

Presence of negri bodies in brain or spinal cord

**not found in all cases

34
Q

Considered as gold standard in diagnosing rabies virus

A

Isolation of virus

35
Q

In virus isolation, what is usually observed for?

A

Rabies antigen and negri bodies

36
Q

It is a serially passaged strain that cannot produce disease in animals so it is used for vaccination (LAV); found in chick embryos

A

Flury strain

37
Q

T or F: rabies virus can still be extracted in dead humans for PCR

A

False

38
Q

Why is immunogenic vaccine or antibody applied immediately

A

To prevent CNS invasion

To provide more time for stimulation of antibodies before CNS invasion

39
Q

Immunization regimen for persons with high risk exposure to rabies

A

Pre-exposure (involves HDCV and DEV)

40
Q

This immunization regimen involves thorough cleansing of the wound, administration of RIG and ARS and immunization with HDCV or DEV

A

Post-exposure

41
Q

T or F: All rabies vaccines administered to humans contain inactivated rabies virus

A

True

42
Q

Where is HDCV grown from?

A

WI-38 human normal fibroblast cell line (free of nervous system and foreign proteins (concentration of virus: ultracentrifugation then it is inactivated with tri-N-butyl phosphate, or Beta-Propiolactone)
Fetal rhesus monkey lung diploid cell line

43
Q

It is sufficiently antigenic and elicits greatest efficacy in antibody response. 4-6 doses are needed.

A

HDCV

  • pre-exposure: 3 times 1 ml
  • post-exposure: 5x 1 ml
44
Q

Developed to minimize post-vaccinal encephalitis, has low antigenicity and can be administered 3-25 times subcutaneously.

A

DEV

**needs multiple doses
Pre-exposure: 3-5x of 1 ml
Post-exposure: 16-25x of 1 ml

45
Q

Rabies glycoprotein is inserted into vaccinia virus; orally given

A

Recombinant virus vaccine

46
Q

It is prepared via cold ethanol fractionation of plasma of hyperimmunized individual. Dose: 20 IU/kg (intramuscular and around bite)

A

Rabies Ig

47
Q

Concentrated horse serum that were hyperimmunized with the rabies virus

A

ARS, equine

Dose: 40 IU/kg

48
Q

Factors to consider in administering post exposure prophylaxis

A
Nature of animal
-HDCV and RIG
Existence of Rabies in area
Manner of attack and biting severity
Advice
49
Q

PEP measure if contact with suspected rabid animal: Touching/feeding animals Licks on intact skin

A

None

50
Q

PEP if contact is nibbling and minor scratches and abrasions

A

Immediate vaccination

Local wound treatment

51
Q

PEP if contact is: Single/multiple transdermal bites/scratches
Licks on broken skin
Contamination of mucous membrane with saliva from licks
Contact s with bats

A

Immediate vaccination
Administration of Ig
Local wound treatment

(3rd category)