Arboviruses (Exam 5)

Question 1

Arbovirus means _______-borne.

Answer 1

arhtropod

Question 2

Arboviruses have a replication cycle in nature involving blood-feeding _______ and ________ host.

Answer 2

arthropod
vertebrate

Question 3

Which 3 species are typically vertebrate hosts for arboviruses?

Answer 3

birds, primates, rodents

Question 4

Hosts that are asymptomatic, tolerant, and subclinical to Arboviruses with a low viremia are called:

Answer 4

reservoirs

Question 5

Hosts that are asymptomatic OR symptomatic with a high viremia are called:

Answer 5

amplifiers

Question 6

Accidental hosts with a low viremia where the disease cycle ends are called:

Answer 6

“dead-end” hosts

Question 7

Benefits of arboviruses are that they easily cross species barrier and be transmitted over winter via which two routes?

Answer 7

transovarial or transstadial (tick)

Question 8

When a virus is amplified in reservoirs or extends beyond usual host range this is called _______ disease.

Answer 8

epidemic

Question 9

In Epidemic Disease, ________ hosts are NOT supportive of replication.

Answer 9

dead-end

Question 10

Reservoir hosts are mostly responsible for arbovirus replication and transmission in a ________ or ______ cycle.

Answer 10

enzootic or endemic

Question 11

Two families discussed that are contain Arboviruses are:

Answer 11

Togaviridae
Flaviviridae

Question 12

What arbovirus disease is caused by an alphavirus within Togaviridae?

Answer 12

Equine Encephalitis

Question 13

Alphaviruses which cause Equine Encephalitis are _______-borne, (enveloped/nonenveloped), (ss/ds) (DNA/RNA) viruses.

Answer 13

arthropod
enveloped ssRNA

Question 14

Alphaviruses primarily use ______ as reservoirs and amplifying hosts. ______ and _______ are “dead-end” hosts.

Answer 14

birds
horses & humans

Question 15

Equine Encephalitis occurs when a mosquito bites and the alphavirus replicates in _________ cells, goes to regional lymph node, and replicates in _______ causing a primary viremia.

Answer 15

dendritic
lymphocytes

Question 16

After Equine Encephalitis causes a primary viremia, muscle, connective tissue, and endothelium are infected, leading to:

Answer 16

secondary viremia

Question 17

Once a secondary viremia occurs in Equine Encephalitis, the virus goes on to infect ________, ______, and endothelium, causing encephalitis.

Answer 17

neurons, glial cells

Question 18

Which 3 alphaviruses cause type of Equine Encephalitis?

Answer 18

Eastern Equine Encephalitis Virus
Western Equine Encephalitis Virus
Venezuelan Equine Encephalitis

Question 19

Which virus causing Equine Encephalitis is the most virulent and severe?

Answer 19

Eastern Equine Encephalitis Virus (EEEV)

Question 20

Fill-in the blanks for Eastern Equine Encephalitis Virus:

Accidental hosts (3): _________
Reservoirs: ________

Answer 20

Accidental: humans, horses, large birds
Reservoirs: marsh birds

Question 21

(T/F) WEEV is nearly 100% fatal in horses.

Answer 21

False (EEEV)

Question 22

Western Equine Encephalitis Virus is a natural recombinant of _______ and non-pathogenic _______ virus.

Answer 22

EEEV
aura

Question 23

(T/F) There are only sporadic cases of WEEV.

Answer 23

True

Question 24

WEEV has 3 epizootic and 5 enzootic lineages but only ________ are neurovirulent.

Answer 24

epizootic

Question 25

Fill-in the blank for WEEV: Accidental hosts (2): _________ Reservoir hosts: ________

Answer 25

horses, humans wild birds

Question 26

Which alphavirus causing Equine Encephalitis is a reportable foreign animal disease?

Answer 26

Venezuelan Equine Encephalitis V (VEEV)

Question 27

Which Equine Encephalitis has the highest zoonotic risk, as horses are amplifying hosts?

Answer 27

Venezuelan Equine Encephalitis (VEEV)

Question 28

Fill-in the blank for VEEV: Accidental host (2): ________ Amplifier: ________

Answer 28

humans, dogs (rare) horses

Question 29

Horses with VEEV have a (low/high) viremia and are (infectious/non-infectious).

Answer 29

high infectious

Question 30

Which Equine Encephalitis virus only uses humans as the "dead-end" host and not horses?

Answer 30

VEEV

Question 31

Clinical Disease/Syndromes of Equine Encephalitis can occur in two forms:

Answer 31

1. inapparent/subclinical 2. encephalitis

Question 32

(T/F) You can distinguish between Equine Encephalitis viruses based on the clinical signs.

Answer 32

False

Question 33

Depression, anorexia, drooping ears, and swollen eyelids are all signs of Encephalitis in horses together called:

Answer 33

"Sleeping Sickness"

Question 34

Apart from "Sleeping Sickness" signs, non-specific ________ signs can occur in horses with Encephalitis.

Answer 34

neurologic

Question 35

(T/F) There are NO gross lesions observable with Equine Encephalitis.

Answer 35

True

Question 36

Encephalitis in horses presents as a (suppurative/nonsuppurative) __________.

Answer 36

non-suppurative polioencephalomyelitis

Question 37

Regarding diagnosis of Equine Encephalitis, the virus can only be isolated when its in the blood during _________.

Answer 37

fever

Question 38

What is the main method for antemortem diagnosis of Equine Encephalitis?

Answer 38

serology

Question 39

In horses, which types of Equine Encephalitis are considered core vaccines?

Answer 39

EEEV WEEV

Question 40

Within the family Flaviviridae, which veterinary relevant virus is also a mosquito-borne arbovirus?

Answer 40

West Nile Virus

Question 41

West Nile Virus within the family Flaviviridae is witin the genus:

Answer 41

Flavivirus

Question 42

West Nile Virus, of Genus Flavivirus, is a(n) (enveloped/nonenveloped) (positive/negative) sense (ss/ds) (DNA/RNA) virus.

Answer 42

enveloped positive ssRNA

Question 43

Flavivirus uses _______ for receptor ligand binding and cell fusion.

Answer 43

E protein

Question 44

(T/F) West Nile Virus is a reportable disease in Missouri.

Answer 44

False (not anymore)

Question 45

West Nile Virus is the leading cause of _______ arboviral encephalitis in the US.

Answer 45

human

Question 46

80% of humans infected with West Nile Virus are asymptomatic. The rest develop ________ form or non-_________ form.

Answer 46

neuroinvasive

Question 47

List 3 species that can be affected by West Nile Virus.

Answer 47

birds humans horses

Question 48

Fill-in the host information for WNV: Primary amplifying hosts (2): _________ Environmental sentinels: _________ "Dead-End" hosts (2): _______

Answer 48

house sparrow, robin corvids (blue jay, crow, magpies) humans, horses

Question 49

_______ are possible amplifying hosts for West Nile Virus.

Answer 49

alligators

Question 50

Regarding WNV, once a mosquito bites, the virus replicates in ________ and _______ cells causing a viremia which disseminates to CNS, causing encephalitis.

Answer 50

fibroblasts endothelial cells

Question 51

(T/F) Clinical signs for WNV are highly variable and not diagnostic.

Answer 51

True

Question 52

Apart from sudden neurologic disease caused by WNV in horses, what two other common clinical signs can be seen?

Answer 52

colic or gait abnormalities muscle fasciculations

Question 53

While gross lesions are not always visible with WNV, encephalomyelitis and _________ in the spinal cord, midbrain, or medulla can occur.

Answer 53

hemorrhage/congestion

Question 54

List 2 main diagnostic tests used for WNV.

Answer 54

IgM antibody capture ELISA serum neutralization