Insect Vectors

Question 1

Vector borne transmission can be mechanical or biological. Describe what mechanical transmission is. (Biological to come later)

Answer 1

Mechanical:

• Transmission by pathogen feet, hairs or mouthparts.
• Physical transference of pathogen from point A to point B.
• Pathogen doesn’t change form.

Question 2

What are the 3 biological forms of pathogen transmission?

Answer 2

1. Propagative
2. Cyclo-developmental
3. Cyclo-propagative

Question 3

Describe propagative transmission. Give an example of a virus that is transmitted in this manner.

Answer 3

Propagative: pathogen multiplies in the arthropod vector. Does not change form.

Example: arbovirsus

Question 4

Describe cyclo-developmental transmission and give an example of a virus that is transmitted this way.

Answer 4

Cyclo-developmental: pathogen changes form but doesn’t multiply (the pathogen DEVELOPS)

Example: filarial worms

Question 5

Describe cyclo-propagative transmission. Give 2 examples of pathogens that are transmitted this way.

Answer 5

Cyclo-propagative: pathogen changes in form AND multiplies

Example: Malaria, Leishmania

Question 6

What are some basic characteristics of arthropods?

Answer 6

1. Exoskeleton
2. Bilateral symmetry w/ segmental bodies
3. Each segment has pair of jointed appendages
4. Most have compound eyes w/ 1+ simple eyes
5. Most have open, hemocoel, body cavity
6. Open circulatory system; tubular alimentary canal

Question 7

How does the open circulatory system help the pathogen out?

Answer 7

Allows it to move freely to the best spot (one that allows it to transmit to another host). Like malaria can easily move to the salivary glands.

Question 8

Tell me about the most medically important group of arthropods: mosquitoes (family: Culicidae)

Answer 8

1. Wings w/ scales
2. Only females feed on human blood (have needle snout); both feed on sugars of flowers
3. Immature stages are entirely aquatic

Question 9

What are examples of good breeding grounds for mosquitoes

Answer 9

Any open body of water (clean, brackish, polluted–mosquitoes don’t give a shit)

1. Temporary pools
2. Permanent pools
3. Artificial containers (loose tires, soda cans)
4. Natural containers (in water build up on leaves)

Question 10

Mosquito genus Anopheles. Tell me moreeeee (don’t know how much of this we should know so I put it all. Enjoy)

Answer 10

1. Female has 45 degree blood feeding posture

2. Permanent/temporary water breeders

Question 11

What is Anopheles a dz vector for

Answer 11

1. MALARIA
2. Bancroftian filariasis
3. Brugian filariasis
4. Arbovirus

Question 12

Mosquito genus Culex: tell me all the things

Answer 12

Female has blunt distal end of abd. Larvae have long respiratory siphons

Question 13

What is Culex a dz vector for?

Answer 13

1. West Nile
2. St. Louis encephalitis
3. WEE/ VEE
4. Japanese encephalitis
5. Ross River virus
6. Bancroftian filariasis

*(1-5 are all arboviruses; 6 is a worm)

Question 14

Mosquito genus Aedes. Tell me

Answer 14

1. Breed in temporary pools and containers

2. Eggs laid single on edge of pool or container

Question 15

What is Aedes a dz vector for?

Answer 15

1. Dengue
2. Yellow fever
3. Chikungunya virus
4. Zika
5. Bancroftian filariasis

Question 16

NEW mosquito family: Psychodidae (Sand Flies)

Answer 16

1. Small (

Question 17

Medical importance of sand flies?

Answer 17

1. Leishmaniasis
2. Barontellosis
3. Sand fly fever

Question 18

Family: Simuliidae (Black flies)

Answer 18

Aka buffalo flies (hump back flies)

1. Vector for Onchocerciasis (river blindness, filarial worms)
2. Larvae found in fast moving water

Question 19

Family: Glossinidae (Tsetse Fly)

Answer 19

1. Both male and female feed only on blood
2. African trypanosomiasis (sleeping sickness)
3. Big in Africa

Question 20

Order: Hemiptera; Family Reduviidae (kissing bugs or conenoses)

Answer 20

1. vector for Chagas disease (American trypanosomiasis)
2. Big in South America
3. Attack people while sleeping and suck blood from up to 20 minutes EWWWW

Question 21

Order: Phthiraptera (aka lice). Forms are:

Answer 21

1. Body Louse
2. Head louse
3. Crab louse

Question 22

Important things about body louse

Answer 22

1. leads to epidemic typhus (from rickettsia prawazekii)
2. Fever (from borrelia recurrentis)
3. Trench fever (from bartonella quintana)

Question 23

Order: Siphonaptera (Fleas)

Answer 23

1. Wingless

2. Laterally flattened

Question 24

Medical importance of fleas

Answer 24

1. Vector for yersinia pestis
2. Can transmit Rickettsia typhi
3. Chigoe/Jigger fleas burrow in your feet causing tungiasis

Question 25

Cockroaches. Ew.

Answer 25

1. Can contribute to allergic asthma | 2. can carry many other viruses, protazoa, bacteria etc (too many to list. and also, i don't care anymore.)

Question 26

Filth Flies (house flies, flesh fly, blow fly)

Answer 26

1. Breed in filth 2. Transmit lots of disease 3. Transmission: regurgitation, contamination, defectation

Question 27

Human bot fly

Answer 27

Females lay eggs on blood sucking insects. When the insect lands on you the heat from your body causes the egg of drop onto your skin. Neat-o. Causes painful boil like lesions with sensation of movement.

Question 28

3 Important things about what mites can cause

Answer 28

1. Scabies 2. Chiggers: scrub typhus (fever, lesion, rash, lymphadenopathy) 3. House dust mites: allergic reactions, rhinitis, eczema 4. Follicle mites: stick in your hair follicle and eat you. I'm about to vomit. Thank god this is the last card.