Insect Vectors Flashcards
Vector borne transmission can be mechanical or biological. Describe what mechanical transmission is. (Biological to come later)
Mechanical:
- Transmission by pathogen feet, hairs or mouthparts.
- Physical transference of pathogen from point A to point B.
- Pathogen doesn’t change form.
What are the 3 biological forms of pathogen transmission?
- Propagative
- Cyclo-developmental
- Cyclo-propagative
Describe propagative transmission. Give an example of a virus that is transmitted in this manner.
Propagative: pathogen multiplies in the arthropod vector. Does not change form.
Example: arbovirsus
Describe cyclo-developmental transmission and give an example of a virus that is transmitted this way.
Cyclo-developmental: pathogen changes form but doesn’t multiply (the pathogen DEVELOPS)
Example: filarial worms
Describe cyclo-propagative transmission. Give 2 examples of pathogens that are transmitted this way.
Cyclo-propagative: pathogen changes in form AND multiplies
Example: Malaria, Leishmania
What are some basic characteristics of arthropods?
- Exoskeleton
- Bilateral symmetry w/ segmental bodies
- Each segment has pair of jointed appendages
- Most have compound eyes w/ 1+ simple eyes
- Most have open, hemocoel, body cavity
- Open circulatory system; tubular alimentary canal
How does the open circulatory system help the pathogen out?
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.
Tell me about the most medically important group of arthropods: mosquitoes (family: Culicidae)
- Wings w/ scales
- Only females feed on human blood (have needle snout); both feed on sugars of flowers
- Immature stages are entirely aquatic
What are examples of good breeding grounds for mosquitoes
Any open body of water (clean, brackish, polluted–mosquitoes don’t give a shit)
- Temporary pools
- Permanent pools
- Artificial containers (loose tires, soda cans)
- Natural containers (in water build up on leaves)
Mosquito genus Anopheles. Tell me moreeeee (don’t know how much of this we should know so I put it all. Enjoy)
- Female has 45 degree blood feeding posture
2. Permanent/temporary water breeders
What is Anopheles a dz vector for
- MALARIA
- Bancroftian filariasis
- Brugian filariasis
- Arbovirus
Mosquito genus Culex: tell me all the things
Female has blunt distal end of abd. Larvae have long respiratory siphons
What is Culex a dz vector for?
- West Nile
- St. Louis encephalitis
- WEE/ VEE
- Japanese encephalitis
- Ross River virus
- Bancroftian filariasis
*(1-5 are all arboviruses; 6 is a worm)
Mosquito genus Aedes. Tell me
- Breed in temporary pools and containers
2. Eggs laid single on edge of pool or container
What is Aedes a dz vector for?
- Dengue
- Yellow fever
- Chikungunya virus
- Zika
- Bancroftian filariasis
NEW mosquito family: Psychodidae (Sand Flies)
- Small (
Medical importance of sand flies?
- Leishmaniasis
- Barontellosis
- Sand fly fever
Family: Simuliidae (Black flies)
Aka buffalo flies (hump back flies)
- Vector for Onchocerciasis (river blindness, filarial worms)
- Larvae found in fast moving water
Family: Glossinidae (Tsetse Fly)
- Both male and female feed only on blood
- African trypanosomiasis (sleeping sickness)
- Big in Africa
Order: Hemiptera; Family Reduviidae (kissing bugs or conenoses)
- vector for Chagas disease (American trypanosomiasis)
- Big in South America
- Attack people while sleeping and suck blood from up to 20 minutes EWWWW
Order: Phthiraptera (aka lice). Forms are:
- Body Louse
- Head louse
- Crab louse
Important things about body louse
- leads to epidemic typhus (from rickettsia prawazekii)
- Fever (from borrelia recurrentis)
- Trench fever (from bartonella quintana)
Order: Siphonaptera (Fleas)
- Wingless
2. Laterally flattened
Medical importance of fleas
- Vector for yersinia pestis
- Can transmit Rickettsia typhi
- Chigoe/Jigger fleas burrow in your feet causing tungiasis
Cockroaches. Ew.
- 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.)
Filth Flies (house flies, flesh fly, blow fly)
- Breed in filth
- Transmit lots of disease
- Transmission: regurgitation, contamination, defectation
Human bot fly
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.
3 Important things about what mites can cause
- Scabies
- Chiggers: scrub typhus (fever, lesion, rash, lymphadenopathy)
- House dust mites: allergic reactions, rhinitis, eczema
- Follicle mites: stick in your hair follicle and eat you. I’m about to vomit. Thank god this is the last card.
