Exam II

Question 1

What country was able to eliminate river blindness?

Answer 1

Colombia

Question 2

Top 2 important factors that make mosquitoes good disease vectors.

Answer 2

1. Taking a blood meal - a major way to acquire a pathogen
2. The vector has to live long enough to pass it to another susceptible host. This can be a week or more if the pathogen develops or multiplies in the vector.

Question 3

Mechanical transmission

Answer 3

Carry physically on body or by interrupted feeding - no development
Transfer via legs, etc.

Question 4

Biological transmission

Answer 4

Cyclodevelopmental - develops
Propagative - pathogen multiples
Cyclopropagative - develops and multiplies

Question 5

Pathogens can get into the new host.

Answer 5

Penetrate vector gut wall, move to salivary glands

Question 6

What are 7 characteristics of a good vector?

Answer 6

1. Can acquire, maintain, and transmit pathogens
2. Provides suitable internal environment
3. Lives for some min. time
4. Feeding pattern matches pathogen host range
5. Feeds often for extended periods
6. Ingest large amounts of blood
7. Be able to disperse

Question 7

Diptera represents

Answer 7

Two wings = “true flies”

Question 8

Diptera adults have:

Answer 8

1 pair of wings

Variable mouthparts? None, piercing/sucking, slashing, sponging

Question 9

Many ways to think about flies (3)

Answer 9

1. Classification: 3 main taxonomic groups
2. How they feed: piercing-sucking, sponging
3. Where they breed: water, mud, manure

Question 10

Diptera larvae

Answer 10

No legs, with/without distinct head
Soft, thin cuticle
Aquatic, semi-aquatic, moist habitats, in tissues

Question 11

Female mosquitoes/gnats are ______. Males are _____.

Answer 11

Blood feeder; nectar feeders

Question 12

Primitive mosquitoes and gnats have…

Answer 12

Long antennae: 8 segments

Question 13

Host-finding: Long range

Answer 13

Host-specific odors

Question 14

Host-finding: Medium range

Answer 14

Host odors + CO2

Question 15

Host-finding: Close/Final decision

Answer 15

• Warmth - convection currents, vision / movement (Day biters)
• Specific attraction to host
• Olfactory (smell) receptors on antennae
• Noranal - volatile skin chemical given off from birds and humans aids in long range detection (+ CO2)
  Lactic acid, CO2, ammonia, fatty acids

Question 16

House mosquito shifts feeding preference from _____ to _____ in late _____ / early _____ – at time of robin dispersal/migration

Answer 16

birds to humans

summer; fall

Question 17

3 Factors in host attractiveness

Answer 17

1. Body odors – skin bacteria
2. Dark colors : Pregnancy – 1 degree warmer, exhale 20% more CO2
3. Blood type – O 2x > A

Question 18

A person who eats human flesh

Answer 18

Anthropophagic

Question 19

An organism that consumes animal matter

Answer 19

Zoophagic

Question 20

An organism that consumes birds

Answer 20

Ornithophagic

Question 21

Mosquito bites -

Answer 21

Stylets protected by sheath, Enter capillary

Question 22

There are _____ proteins in saliva - anti-coagulants, vasodilators, numbing agents, suppress anti-viral response.
Stimulate _____

Answer 22

> 10

Stimulate antibody response

Question 23

How to think about > 50 mosquito species in KY:

Answer 23

1) Oviposition sites / Larval habitats
2) Overwintering stage
3) Number of generations/year

Question 24

1) Eggs/larvae

Answer 24

• Single, groups, floating “rafts”
• Desiccation resistant or not
• In/on: ground depressions, floodwater, natural or artificial containers – buckets, tree holes,
  surface of “dirty” water, etc.

Question 25

2) Overwintering stage Eggs – resistant to _____, drying Mated females – in _____ Larvae – _____ - a few in mild climates

Answer 25

Cold; shelter; rare

Question 26

A genetically determined state of arrested development that allows arthropods to overwinter in cold climates

Answer 26

Diapause

Question 27

Diapause is induced primarily by _____

Answer 27

decreasing shorter daylight

Question 28

Diapause has different stages based on _____

Answer 28

species

Question 29

Diapause: _____ in blood or freezing in spaces between cells

Answer 29

Antifreeze

Question 30

3) Generations / year One - _____ peak or extended emergence – _____; 2+ – _____

Answer 30

spring; univoltine; bivoltine or multivoltine

Question 31

Generations can change with season – For example...

Answer 31

Warmer season, extra generation

Question 32

2 main reasons for variation in mosquito populations

Answer 32

Rainfall and temperature

Question 33

3 reasons why mosquitoes are a problem

Answer 33

1. Nuisance/ annoyance 2. Blood loss – can lead to anemia 3. Vector human/animal diseases – zoonosis encephalitis

Question 34

Example mosquito species: 1. Inland floodwater mosquito _____ 2. House mosquito _____ 3. Asian tiger mosquito _____

Answer 34

Aedes vexans; Culex pipiens complex; Aedes albopictus

Question 35

Inland floodwater mosquitoes are a serious nuisance species. 4 reasons why:

Answer 35

1. Night biter 2. Rests on vegetation during day 3. Not an important disease vector 4. Can fly 10+ miles to feed

Question 36

``` 1) Inland floodwater mosquito • Winter - eggs in _____ in low areas • Hatch when covered w/ _____ • Unshaded rain pools • Problem during rainy spring /early summer • Multivoltine ```

Answer 36

soil cracks; w/water and O2 drop;

Question 37

2) House mosquito complex “dirty” water mosquitoes Northern and southern house mosquito and hybrids – they can _____ • Live in urban and rural areas • Feed on _____ • NHM have a stronger _____ preference • Females winter in _____ sites - culverts and caves

Answer 37

interbreed; birds & mammals; NHM - bird; females - protected

Question 38

House mosquito Culex pipiens complex - Can return to larval breeding site to oviposit BUT can travel _____ to feed - Commonly enters structures - Prefers _____, will feed on mammals: humans, raccoons, horses - Can carry (competent vector for) _____ viruses

Answer 38

1,500 yards/night; birds (robins, house sparrows); Encephalitis, Dog heartworm

Question 39

4 Factors that affect mosquitoes as disease vectors

Answer 39

1) Abundance –enough numbers to encounter infected host 2) Longevity – live long enough after feeding for pathogen to reach salivary glands 3) Competent – able to carry enough pathogen to be infective, don’t become sick themselves 4) Strong host selection behavior – reliable, contact with susceptible hosts

Question 40

Infectious disease transmitted between species (sometimes by a vector) from animals to humans

Answer 40

Zoonosis

Question 41

About _____% of human-emerging infectious diseases are caused by zoonotic pathogens

Answer 41

75%

Question 42

``` Encephalitis virus • Symptoms • Also called: Eastern equine, St Louis, Venezuelan, West Nile • Bird – mosquito cycle • Spillover into _____ ```

Answer 42

Inflammation or swelling of the brain affects CNS | Spillover from birds to humans, livestock

Question 43

First case in US: West Nile Virus

Answer 43

1999 NY Transovarian transmisson in mosquitoes Mosquitoes live 2 to 3 weeks; feed 3x to 4x

Question 44

Incubation period in mosquitoes = _____ gut to salivary glands Birds amplifying host - infective _____ Incubation period in horses _____ – ___% recovery

Answer 44

7-10 days; 5 days; 7-14 days with 65% recovery