L18: Veterinary Virology (Waltzek)

Question 1

virus

Answer 1

obligate intracellular pathogens that are unable to direct any biosynthetic processes outside the host cell
-smaller and simpler than bacteria

Question 2

do viruses have functional ribosomes?

Answer 2

no

Question 3

Edward Jenner

Answer 3

used cowpox to vax for smallpox

Question 4

Louis Pasteur

Answer 4

“father of microbiology”

-developed rabies vax, pasteurization

Question 5

first pig epizootic

Answer 5

swine influenza; discovered by Shope in 1931

Question 6

Koch’s postulates

Answer 6

• agent must be present in every case of dz
• agent must be isolated from the host and grown in vitro
• dz must be reproduced when the pure cultivated agent is introduced into a healthy susceptible host
• same agent must once again be recoverable from the newly infected host

Question 7

virales refers to

Answer 7

order

Question 8

viridae refers to

Answer 8

family

Question 9

virinae refers to

Answer 9

subfamily

Question 10

virus refers to

Answer 10

genus

Question 11

how are viruses classified?

Answer 11

• architecture
• nucleic acid
• phylogenomics
• antigenic relationships (serology)
• biologic characteristics

Question 12

what is a virion?

Answer 12

completed infectious virus particle

-contains nucleocapsid +/- host-derived envelope

Question 13

nucleocapside

Answer 13

nucleic acid (RNA or DNA) core enclosed in protein coat (capsid)

Question 14

what is virus envelope composed of?

Answer 14

glucoprotein studded phospholipid membrane

Question 15

which are more durable: enveloped or non-enveloped viruses?**

Answer 15

non-enveloped

-survive better outside host and less susceptible to disinfectants

Question 16

types of nucleocapsid shapes

Answer 16

symmetrical (icosahedral, heical)

non-symmetrical (complex, filamentous, pleomorphic)

Question 17

icosahedral nucleocapsid

Answer 17

has 20 equilateral triangular faces (i.e. FMDV, rhabdoviruses)

Question 18

helical nucleocapsid

Answer 18

coiled appearance (i.e. rabies)

Question 19

complex nucleocapsid

Answer 19

i.e. smallpox

Question 20

filamentous nucleocapsid

Answer 20

thread-like i.e. ebola

Question 21

Types of viral nucleic acids

Answer 21

dsDNA
ssDNA
dsRNA
ssRNA
*all must make mRNA --> translation --> proteins --> virus

Question 22

viruses with dsDNA genomes

Answer 22

(Class I viruses)
Papillomaviridae (papillomaviruses)
Adenoviridae (adenoviruses)
Herpesviridae (bovine/equine herpesvirus, porcine cytomegalovirus)
Poxviridae (poxviruses)
Asfaviridae (African swine fever virus)

Question 23

viruses with ssDNA genomes

Answer 23

(Class II viruses)
Circoviridae (porcine circovirus)
Parvoviridae (canine parvovirus, feline panleukopenia, porcine parvo)

Question 24

viruses with dsRNA genomes

Answer 24

(Class III viruses)
Reoviridae (rotaviruses, bluetonge virus, african horse sickness)
Birnaviridae (infectious bursal disease, infect. pancreatic necrosis)

Question 25

role of phylogenetics

Answer 25

confirms previously established taxononic schemes based on virion architecture, NA type, etc.

Question 26

ex. of antigenic relationships (serology)

Answer 26

how host mounts immune response to viral proteins Hemagglutinin (H) and Neuraminidase (N)

Question 27

viruses with ssRNA(+) Genomes

Answer 27

(Class IV viruses)
Picornaviridae (foot/mouth dz, porcine enteroviruses)
Caliciviridae (feline calicivirus)
Coronaviridae (feline coronaviruses)
Arteriviridae (equine arterivirus)
Flaviviridae (pestiviruses, flaviviruses)
Togaviridae (alphaviruses)

Question 28

viruses with ssRNA(-) Genomes

Answer 28

(Class V viruses)
Orthomyxoviridae (influenza)
Paramyxoviridae (parainfluenza, distemper, resp. syncytial)
Rhabdoviridae (rabies, vesicular stomatitis)
Filoviridae (ebola)
Bunyaviridae (Haantan virus)

Question 29

viruses with Reverse Transcriptase

Answer 29

(Class VI and VII)
Retroviridae (feline leukemia, feline/bovine immunodeficiency, bovine/avian leukosis viruses, caprine arthritis-encephalitis virus)
Hepadnaviridae

Question 30

grouping of viruses on the basis of biologic properties is based on

Answer 30

virus tropisms and modes of transmission
Categories:
-enterics, respiratory viruses, arboviruses, oncogenic viruses

Question 31

generalized viral life cycle

Answer 31

attachment
penetration
uncoating
replication
transcription
translation
assembly
release

Question 32

virus induced cellular changes

Answer 32

necrosis/apoptosis (Cytopathic Effect)
cell transformation (i.e. –> neoplasia)
no discernible effect

Question 33

which viruses are shed at SURFACE of skin, mm, resp. tract, GIT

Answer 33

herpes

papillomavirus

Question 34

Which viruses are shed in blood?

Answer 34

hepatitis B
poliovirus
HIV

Question 35

enteric viruses

Answer 35

-usually acquired by ingestion (fecal/oral)
-replicate primarily in intestines
Examples:
-Picornaviridae
-Caliciviridae
-Astroviridae
-Coronaviridae
-Reoviridae
-Parvoviridae
-Adenoviridae

Question 36

Respiratory viruses

Answer 36

-acquired by inhalation and replicate in resp. tract
Examples:
-Picornaviridae
-Caliciviridae
-Coronaviridae
-Paramyxoviridae
-Orthomyxoviridae
-Adenoviridae

Question 37

Arboviruses

Answer 37

-undergo a natural vector-vertebrate-vector cycle
-replicate in host, transmitted by arthropod
Examples:
-Togaviridae, Flaviviridae, Rhabdoviridae, Bunyaviridae, Reoviridae

Question 38

Oncogenic viruses

Answer 38

-acquired by close contact, injection, fomites, sex. contact
-usually only infect specific cells in target tissues, and may transform these cells –> neoplasia
Examples:
-Retroviridae
-Hepadnaviridae
-Papillomaviridae
-Adenoviridae
-Herpesviridae