Insect Vectors Flashcards
Vector-borne Disease Transmission
Mechanical
Biological
- Propagative*
- Cyclo-developmental*
- Cyclo-propagative*
Mechanical transmission
Transmission of pathogen by feet, hairs or mouthparts
Pathogen does not change form or multiple
Propagative transmission
Pathogen multiples in the arthropod vector
Cyclo-developmental transmission
Pathogen changes form, but doesn’t multiply
Cyclo-propagative
Pathogen changes form AND multiplies
Example of mechanical transmission
House fly
Example of propagative transmission
Arboviruses
Example of cyclo-developmental transmission
Filarial worms
Example of cyclo-propagative transmission
Malaria
Leishmania
Jointed Foot
Has exoskeleton, bilateral symmetry, segmented body, and open circulatory system
Arthropod
Hexapoda
aka Insects:
Mosquitos
Sand flies
Black flies
Tsetse fly
Reduviidae
Lice
Rat fleas
Cockroaches
Different types of mosquitos
All mosquitos have wings with scales, long proboscis for sucking, and immature stages that are entirely acquatic (larvae)
-
Anopheles mosquitos: larvae rests parallel to water surface and lacks Siphon; 45 degree blood feeding posture
- Malaria, arboviruses
-
Culex: larvae with long respiratory siphons, eggs laid in rafts, female has blunt distal end of abdomen
- Arboviruses (West Nile)
-
Aedes: eggs laid singly, breed in temporary pools
- Arboviruses (Dengue, Yellow Fever)
Sand Flies
Long antennae and hair on body/wings
Sand Fly Fever, Bartonellosis, Leishmaniasis (Cutaneous, Mucocutaneous, and Visceral)
Note: U.S. has sand flies capable of carrying leishmaniasis, but they don’t currently have it
Black flies
Small, hump-backed flies
Larvae in fast moving water
River blindness (onchocerciasis due to filarial worms)
Black flies make your vision go black
Tsetse Fly
Feed only on blood
Produce 1 young at a time
Trypanosomiasis (sleeping sickness)
Reduviidae (kissing bugs or conenoses)
Bite causes little or no pain
Bug habitat = South American homes (walls)
Chagas disease (American trypanosomiasis) passed in bug feces and rubbed into bite site
Lice
Body louse, Head louse, Crab (pubic) Louse
From overcrowding, wars, famine, or natural disasters
Epidemic typhus (Rickettsia prowazekii), Epidemic Relapsing Fever (Borrelia recurrentis), Trench Fever (Bartonella quintana)
Stercorarian Transmission
Feces gets rubbed into skin
Ex: Kissing bugs or Lice
Rat fleas
Intermediate host for tape worms/cestodes; mechanical vectors of F. tularensis
Plague (Yersinia pestis), Endemic Murine Typhus (R. typhi),
Cockroaches
Common mechanical vectors
Terrible for asthmatics
Myiasis
Invasion of tissues and organs of LIVING vertebrates by LARVAE of the human bot fly (Dermatobia)
Females lay eggs on blood sucking insects, that then land on you, causing singular lesions that are very painful and cause the sensation of movement
Maggot Therapy: kills some bacteria and destroys dying tissue
Arachnida
Tick/Mites
Ixodes (Hard deer tick)
Lyme, Babesia and anaplasmosis
Note: anaplasmosis was previously known as human granulocytic ehrlichiosis (HGE); now it is known as HGA
Dermacentor (american dog tick)
RMSF
Tularemia
Amblyomma (lone star tick)
Ehrlichiosis (fever, fatigue, headache, muscle aches)
Treat w/ doxy
STARI (similar to lyme)
Soft shell ticks
Endemic relapsing fever
(Borrelia hermsii)
Scabies
Chiggers
House dust mites
Mites (scabies)
Scrub typhus (chiggers)
Asthma (dust mites)
Rhinitis (dust mites)
Eczema (dust mites)
