Intro & Viral Pathogenesis I (Exam 1)

Question 1

Viruses gain new _________ so that they cause outbreaks in those new hosts.

Answer 1

host ranges

Question 2

What occurs in viruses for them to result in infection and disease in new host species?

Answer 2

gene mutation

Question 3

Viral mutations which cause infection of a new cell type, a different effect on cells, or increased viral replication can lead to an increased ________ of disease in the host.

Answer 3

severity

Question 4

Many viral mutations do not cause dramatic changes in disease or host range, but instead result in _________.

Answer 4

antigenic drift

Question 5

Mutation of viral genes for surface proteins is called:

Answer 5

antigenic drift

Question 6

Viruses hijack cell processes for what purpose?

Answer 6

replication

Question 7

Term for the vehicle for transmission of a virus.

Answer 7

virions

Question 8

The structure of viruses includes a _______ core and an outer shell of viral proteins that is heat and drying resistant called _________.

Answer 8

nucleic acid
capsid

Question 9

(T/F) Viruses can be DNA or RNA viruses.

Answer 9

True

Question 10

A positive PCR test for FIP will indicate that the disease is present in that patient.

Answer 10

False - immunocytochemistry is best test

Question 11

List the 3 groups of animal viruses.

Answer 11

DNA viruses
RNA viruses
RT viruses (reverse transcribing)

Question 11

(T/F) All viruses have an envelope.

Answer 11

False

Question 12

The process by which the envelope is acquired from the host cell membrane is called:

Answer 12

budding

Question 13

(T/F) Viruses with an envelope survive longer in the environment than non-enveloped viruses.

Answer 13

False - opposite

Question 14

Non-enveloped viruses are released from an infected cell via what process?

Answer 14

lysis

Question 15

Nuclear or cytoplasmic aggregates of viral substances, usually capsid proteins, are called:

Answer 15

viral inclusion bodies

Question 16

Viral inclusion bodies suggest what process?

Answer 16

viral multiplication

Question 17

What 3 methods of entry to viruses use to get into a host cell?

Answer 17

membrane fusion
endocytosis
pore-mediated penetration

Question 18

_________ is a method of viral entry when the cell membrane is punctured and connects with the unfolding viral envelope.

Answer 18

membrane fusion

Question 19

Where do most DNA viruses replicate? What is the exception?

Answer 19

nucleus
exception: poxvirus (cytoplasm)

Question 20

Where do most RNA viruses replicate? What is the exception?

Answer 20

cytoplasm
exception: retroviruses (nucleus)

Question 21

Term for study of infection and spread of viruses and their mechanisms.

Answer 21

pathogenesis

Question 22

Term for measure of a virus to produce disease.

Answer 22

virulence

Question 23

(T/F) An animal can shed a virus without having the disease or clinical signs.

Answer 23

True

Question 24

Birds are a common _______ for Equine Encephalitis Virus and West Nile Virus in horses as horses do not have high enough titers for transmission.

Answer 24

vector / reservoir host

Question 25

Viruses are transferred by _________ or ________ transmission.

Answer 25

horizontal vertical

Question 26

For most viruses (horizontal/vertical) transmission is the most important route.

Answer 26

horizontal

Question 27

Which type of viral transmission is from parents to offspring?

Answer 27

vertical

Question 28

What are the 3 types of horizontal transmission of viruses?

Answer 28

1. direct contact 2. indirect contact 3. vectors

Question 29

While direct contact transmits viruses via cohabitating animals, indirect contact transmits them via contaminated ________ in the environment.

Answer 29

fomites

Question 30

Through what 4 structures/tissues can viruses be transmitted vertically?

Answer 30

1. germplasm 2. egg 3. placenta 4. milk

Question 31

What are the 3 major routes of viral transmission in veterinary medicine?

Answer 31

1. respiratory 2. oral 3. fecal

Question 32

List 2 ways a host defends itself against a virus transmitted via the respiratory tract.

Answer 32

1. mucociliary clearance 2. alveolar macrophage phagocytosis

Question 33

________ are the main way that viruses are transmitted via the respiratory route.

Answer 33

aerosols

Question 34

A host defends itself from a virus transmitted orally in what 3 ways?

Answer 34

1. gut pH 2. mucous 3. peristaltic movements

Question 35

Trauma and insect bites can transmit viruses via what route?

Answer 35

skin

Question 36

List the 6 major routes of transmission by which viruses infect animals.

Answer 36

1. respiratory 2. oral 3. fecal 4. milk 5. skin 6. urogenital tract

Question 37

A virus can be transmitted via placenta if what occurs in the pregnant female?

Answer 37

viremia (virus in bloodstream)

Question 38

(T/F) If viremia occurs in a late-term gestation, the fetus will become infected and often abort.

Answer 38

False - immunity protects from infection

Question 39

List the 5 mechanisms which viruses can use to cause disease.

Answer 39

1. direct cell damage 2. cell transformation 3. inflammation 4. immunosuppression 5. immune-mediated disease

Question 40

Immunosuppression caused by viruses can lead to ___________ infection.

Answer 40

secondary

Question 41

A viral infection can be ________, all within the same organ system, or _________, resulting in viremia.

Answer 41

localized systemic

Question 42

Whether a viral infection is localized or systemic is determined by:

Answer 42

immune system response to virus

Question 43

In a systemic infection, the virus will penetrate tissue and enter ________ will primary amplification occurs.

Answer 43

lymphatics

Question 44

In systemic infection, after a virus enters the lymphatics, its progeny enter the bloodstream which is referred to as ___________.

Answer 44

primary viremia

Question 45

After primary viremia in a systemic infection, the virus enters central organs of replication and undergoes replication leading to _________.

Answer 45

secondary viremia

Question 46

After secondary viremia in a systemic infection, characteristic signs of disease are seen when what process is occurring?

Answer 46

viral shedding

Question 47

(T/F) Clinical signs appear during primary viremia and secondary viremia.

Answer 47

False - only secondary

Question 48

Why should you take diagnostic samples early for testing for viral infections?

Answer 48

shedding mostly complete once showing clinical signs

Question 49

Recovery from viral infections occurs by depleting cell populations and the immune response. What type of immunity is most important in mediating recovery in active viral infections?

Answer 49

cell-mediated cytotoxic immunity

Question 50

(Localized/Systemic) viral infections occur more rapidly.

Answer 50

localized

Question 51

Term for study of frequency/distribution of viral diseases in a population, necessary for the control of viral spread.

Answer 51

epidemiology

Question 52

The life cycle of a virus requires _______ to infect its next host.

Answer 52

excretion

Question 53

Which virus example causes disease by direct cell damage, leading to organ dysfunction?

Answer 53

Canine Parvovirus

Question 54

List two examples of viruses which cause disease by cell transformation, leading to either production or loss of function.

Answer 54

Bovine Leukemia Virus FeLV

Question 55

Bovine Leukemia Virus is an example of a virus causing disease via cell transformation. What main clinical sign develops?

Answer 55

lymphosarcoma

Question 56

List 2 examples of viruses which cause disease via inflammation, and therefore, cell destruction.

Answer 56

Canine Distemper FIP

Question 57

List 2 viruses that cause disease via immunosuppression.

Answer 57

Canine Distemper BVD

Question 58

Give an example of a virus which causes an immune-mediated disease via antigen-antibody complex accumulation.

Answer 58

Equine Infectious Anemia

Question 59

Canine Distemper is an example a virus which causes a (localized/systemic) disease.

Answer 59

systemic