Insect vectors Flashcards
propagative
cyclo-developmental
cyclo-propagative
Propagative: pathogen multiplies in the arthropod vector (ex. - arboviruses)
Cyclo-developmental: pathogen changes form, but does not multiply (ex. - filarial worms)
Cyclo-propagative: pathogen changes in form and multiplies (ex.- malaria, Leishmania)
culicidae family
mosquitoes
most medically important group of arthropods
wings with scale and moutparts for sucking i
mmature stages are aquatic
anopheles mosquitoes vs culex mosquitoes vs aedes mosquitoes
A –> malaria, filariasis
larvae rest parallel to water and lack siphon
adult has long palps and 45 degree posture
C –> west nile, WEE,VEE, JE, st louis encephalopathy
larvae have long siphons and eggs in rafts
adult with blunt abdomen
Aedes –> dengue, yellow fever, CA, filariasis
temporary pools/containers;single eggs
mosquito with palps that are as long as proboscis or longer are
anopheles malaria carriers!! ** if short palps, not anopheles
sand flies carry what
virus?
bacteria?
protozoa?
biting pest
viruses = sand fly fever
bacteria = bartonellosis
protozoa = leishmaniasis (cutaneous, mucocutaneous or visceral)
black flies/simuliidae
fast moving water (filterfeeders on rocks/vegetation)
vectors of onchocerciasis (river blindness, filarial worms)
tsetse fly
glossinidae family
**affects african economic development
feed only on blood; produces 1 young at a time
major vectors: glossina palpalis and G. morsitans
central/west african trypanosomiasis = T brucei gambiense (chronic)
east african trypanosomiasis = T brucei rhodesiense (acute)
*T = trypanosoma
Trypanosomiasis - african sleeping sickness
AFRICan sleeping sickness
vector of chagas disease
order hemiptera, family reduviidae (kissing bugs or conenoses)
- TRIATOMA*
- bite actually causes little or no pain
- vectors of Chagas disease (American trypanosomiasis)
- trypanosomes passed in bug feces (stercorarian) and rubbed into the bite site, wounds, nose or eyes
common lice and their classifications
- Pediculus humanus humanus – body louse
- Pediculus humanus capitis – head louse
- Pthirus pubis – crab louse
order = phthiraptera
pediculus humanus humanus
what is it?
how does it transmit?
what 3 diseases ?
BODY LOUSE
ALL STERCORARIAN TRANSMISSION (fecal origin)
- Epidemic typhus Rickettsia prowazekii
- Louse-borne relapsing fever Borrelia recurrentis
- Trench fever Bartonella quintana
fleas
order siphonaptera
- Wingless flat ectoparasites of mammals and birds
- Cause allergic reactions
- Oriental rat flea (Plague, Murine typhus)
plague
vector? pathogen?
Xenopsylla cheopis (Oriental rat flea)
pathogen = Yersinia pestis
murine (endemic) typhus
vector and pathogen?
Xenopsylla fleas
transmit Rickettsia typhi
tungiasis
•Chigoe or jigger flea burrows into the feet of humans causing “tungiasis”
cockroaches
mechanical vectors of enteric diseases
significant contributors to allergens causing allergic asthma
most significant allergen-producing species in multi-family dwellings?
•German cockroach populations
In asthmatics, allergies to cockroaches is second only to house dust mites.
filth flies
•house flies, blow flies, flesh flies
Breed in filthy habitats; transmit >100 disease agents
•Transmission = Regurgitation (liquids from crop), Contamination (sticky feet), or Defecation (probably most important!)
myiasis
Diptera larvae invade tissue and feed on the host’s tissue
Very painful, SINGLE, boil-like lesion with sensation of movement
•caused by human bot fly (Dermatobia hominis)
Females lay eggs on blood sucking insects e. g. mosquitoes
tick lifecycle
2 years to complete
- eggs hatch into uninfected larvae during the summer
- molt to nymphs the following spring
- molt to adults in the fall of the same year
- the activity period of nymphs precedes that of larvae during any given year. As a result, nymphs have the opportunity to feed upon and infect an array of small mammals that will serve as hosts for larvae 6 - 8 weeks later. This phenomenon is largely responsible for the inordinately high infection prevalence of Lyme disease spirochetes in nymphal and adult blacklegged ticks.
lyme disease and borrelia burgdorferi
The feeding tick is basically a blood-sucker. It must keep its host’s blood from clotting in order to continue sucking so it is able to regurgitate assorted enzymes to keep the blood flow liquid and smooth. It is during this regurgitation process that the Lyme spirochete is brought up from the tick’s mid-gut to its mouthparts. This process requires a minimum of 48 hours which means
that if the tick is removed within 48 hours of attachment, the spirochete cannot be transmitted and the host will not get the disease.
