2-Mosquitoes and Zoonoses

Question 1

The pathogen must develop in the mosquito to become what?

Answer 1

Infectious

Question 2

The number of days it takes for the mosquito to become infectious depends on what 3 things?
This time period is known as what?

Answer 2

• Pathogen
• Mosquito
• Temperature
• Extrinsic incubation period

Question 3

When is the disease transmitted by the mosquito?

Answer 3

During feeding.

Question 4

What are the most important vectors of human disease worldwide?

Answer 4

Mosquitoes

Question 5

What is an example of an anthroponotic disease?

Answer 5

Malaria

Question 6

What are 2 examples of mostly anthroponotic diseases?

Answer 6

• Dengue

- Yellow Fever

Question 7

What are 4 examples of true zoonoses transmitted by mosquitoes?

Answer 7

• Rift Valley Fever (FAD)
• Equine encephalitis viruses
• West Nile Virus
• Other flaviviruses

Question 8

What does EEE stand for?

Answer 8

Eastern equine encephalitis

Question 9

What does JE stand for?

Answer 9

Japanese encephalitis

Question 10

What does LAC stand for?

Answer 10

LaCrosse encephalitis

Question 11

What does MVE stand for?

Answer 11

Murray Valley encephalitis

Question 12

What does POW stand for?

Answer 12

Powassan encephalitis

Question 13

What does SLE stand for?

Answer 13

St. Louis encephalitis

Question 14

What does TBE stand for?

Answer 14

Tick-borne encephalitis

Question 15

What does WEE stand for?

Answer 15

Western equine encephalitis

Question 16

What does WN stand for?

Answer 16

West Nile

Question 17

What does VEE stand for?

Answer 17

Venezuelan equine encephalitis

Question 18

What is the viral family of WEE, EEE and VEE?

Genus?

Answer 18

• Togaviridae

- Alphavirus

Question 19

What do EEE, WEE and VEE cause?

In what 2 species?

Answer 19

• Encephalitis and/or febrile disease

- Horses and humans

Question 20

What is the pathogenicity in equids for VEE?
EEE?
WEE?

Answer 20

• Up to 80% case fatality with some strains
• 90+% fatality
• About 20-40% case fatality rate

Question 21

Are mosquitoes mechanical or biological vectors of EEE, WEE and VEE?

Answer 21

Biological vectors

Question 22

With EEE, WEE and VEE, who become infected and develop high enough viral titers in blood to infect mosquitoes?

Answer 22

Reservoir hosts

Question 23

What species is the natural reservoir for WEE and EEE?

Answer 23

Birds

Question 24

What species is the enzootic reservoir for VEE?

The epizootic reservoir?

Answer 24

• Rodents

- Horses

Question 25

How often do epizootics of EEE occur?

Answer 25

Periodically

Question 26

Where do epizootics begin?

Answer 26

In nature.

Question 27

Increased transmission of virus between mosquitoes and birds can lead to what?

Answer 27

Spill over to incidental hosts.

Question 28

T/F: Many environmental factors contribute to spillover cycles.

Answer 28

True

Question 29

What do you call hosts found outside the natural cycle?

Answer 29

Incidental hosts.

Question 30

Incidental hosts are usually what? | What does this mean? What is an exception to this?

Answer 30

- Dead-end hosts | - Can't infect mosquitoes, except both horses and humans with VEE

Question 31

The enzootic reservoir cycle of EEE is between what 2 species?

Answer 31

- Wild birds | - Mosquitoes

Question 32

What is the mosquito vector for EEE?

Answer 32

Culiseta spp.

Question 33

The epizootic cycle of EEE is between birds what what hosts?

Answer 33

Incidental hosts

Question 34

What are 4 examples of incidental hosts of EEE?

Answer 34

- Horses - Humans - Swine - Ratites

Question 35

What is an example of a "bridge" mosquito vector required with EEE?

Answer 35

Aedes spp.

Question 36

Epizootics tend to be what and usually occur within how far of an enzootic swamp habitat?

Answer 36

- Self-limiting | - Within a few miles

Question 37

T/F: Incidental hosts are dead-end.

Answer 37

True

Question 38

Which is most virulent: EEE, WEE, VEE?

Answer 38

EEE

Question 39

Equine cases of EEE often appear how long before human cases?

Answer 39

About 2 weeks

Question 40

Early clinical signs of EEE include what 3 signs?

Answer 40

- Fever - Lack of appetite - Lethargy

Question 41

What disease can progress to various degrees of excitability and then drowsiness, ultimately ending in paresis, seizures and coma in fatal cases?

Answer 41

EEE

Question 42

Is there a vaccine for EEE in horses?

Answer 42

Yes

Question 43

With swine and ratites, what are 2 clinical signs that can be seen with EEE?

Answer 43

- GI disease | - Hepatitis

Question 44

What are 4 other species that can contract EEE?

Answer 44

- Sheep - Cattle - Deer - Camelids

Question 45

What is a risk factor for EEE?

Answer 45

Outdoor activities in an area with EEE-infected mosquitoes.

Question 46

What is the incubation period of EEE?

Answer 46

3-10 days

Question 47

What percentage of people will be asymptomatic with EEE?

Answer 47

90+%

Question 48

What are 4 possible symptoms of EEE in humans?

Answer 48

- Mild flu-like illness - Encephalitis - Coma - Death

Question 49

What percentage of humans survivors of EEE will have mild to severe permanent neurological damage?

Answer 49

Approximately 50-90%

Question 50

What is the estimated lifetime cost per patient for humans with EEE?

Answer 50

$3 billion

Question 51

Is there any specific treatment for EEE?

Answer 51

No

Question 52

What is the mosquito vector for WEE?

Answer 52

Culex tarsalis

Question 53

How are most diseases acquired by mosquitoes?

Answer 53

Via blood meal.