Exam 2: Mosquitos and heartworm Flashcards
diptera
two wings “true flies”
adults mosquitoes wings and mouthparts
1 pair wings
mouthparts - none to piercing-sucking to sponging
diptera undergo what type of metamorphosis
complete
mosquito larva are known as
wigglers
mosquito pupa are known as
tumblers
mosquito larva live in
aquatic, semi-aquatic, or moist habitats
some mosquito larva are
internal parasites
mosquito larva body
no legs, may or may not have distinct head; soft thin cuticle
mosquitos and biting gnats are in the suborder ________ and are known as ______
nematocera; primitive
mosquitoes and biting gnats have what kind of antennae, how many segments
long antennae –> 8 segments
females are ____ feeders while males are ____ feeders
blood; nectar
known as the deadliest animal in the world
mosquitoes
openings on body where air exchange occurs
spiracles
mos larve use what to feed
brushes
adult mos feed on
blood from capillary veins
what is different about mos wings
they have scales
mouthpart that enters capillary veins
stylets - protected by a sheath
what do stylets inject into capillary
saliva, anti-coagulatns, vasodilators
host finding by mosquitoes by distance (long range; medium; close-final decision)
Long range (7 to 30 yds) : hosts specific odors; lactic acid, nonanal, octenol
medium range: host odors + CO2
close range-final decision: warm moist convection currents, vision/movement (day biters)
a substance from birds and humans aids in long range detection
noranal
lactic acid, co2 ammonia fatty acids
skin chemicals determine host suitability
when do house mosquitos shift feeding preferences from birds to humans?
late summer/early fall - at the time of robin migration - this is when more cases of WNV occur
differences in host attractiveness
pregnant - wamer and more CO2
blood type O is 2x > than A
body odors
dark clothing
mosquito eggs/ oviposition sites
laid in groups
desiccation resistant
temporary water/standing water
natural and artificial containers
larval habitats
snow pool; brackish water swamps; temporary or permanent high organic content water; treeholes, outdoor flower vases etc
generations/year
one - spring peak or extended emergence
multiple during summer
overwintering stage
eggs-many species-resistant to cold, drying
mated females-some (house)
larvae-few in mild climates
a genetically determined state of arrested development
diapause- allows arthropods to overwinter in cold climates
induced by decreasing day length
night biter; not important disease vector; can fly 10+ miles to feed
spends winter as eggs in soil cracks in low areas
eggs hatch when covered with water and O2 drops
Inland floodwater mosquito
“dirty” water mosquitoes; common in urban and rural settings; feed on birds and mammals (important as far as disease vectors go)
females often return to breeding site but can travel 1,500 yds per night to feed
commonly enter structures
can carry encephaliti, dog heartworms
nuisance as biters
house mosquito complex
factors that affect mosquitoes as disease vectors
abundance-high enough #’s to encounter infected host
longevity-live long enough after feeding for pathogen to reach salivary glands
competent-able to carry enough pathogens to be infective, dont become sick themselves
strong host selection behavior-reliable , contact wit susceptible hosts
time form when a pathogen is picked up to when it can be transmitted
incubation time
what % of human emerging infectious diseases are caused by zoonotic pathogens
75%
infectious disease transmitted between species from animals to humans or vice versa
zoonosis
encephalitis virus
inflammation or swelling of the brain - affects CNS
WNV transmitted by
transovarian transmission in mosquitoes
incubation period of WNV
7-10 days, virus moves from gut to salivary glands
birds are what type of host for WNV
amplifying host - where to organism or virus increases in number
incubation period in horses of WNV
7-14 days - 65% recovery
WNV reservoir
amplification in birds
bridge vectors
mosquitoes - bridge vectors between birds and humans/other animals
dead end hosts
host gets pathogen but doesn’t produce it/amplify it in their body
blood brain barrier
keeps brain blood from mixing with body blood - not great in horses
what types of birds are the main amplyfiying hosts of WNV
robins and sparrows
what type of bird is the sentinel hosts ( gets sick form virus)
crow
How much does WNV move during spread
40 miles/month
why did WNV decrease so much in ky in two years
birds-susceptible killed, resistant left horses-immnization humans-immunity lower mos pop's weather- less rain? tents to be in concentrated water
how to reduce potential of WNV in horses
vaccinate; stable during mos feeding peak times; no incandescent lights; screening; fans; eliminate breeding sites
nuisance and health threat; wide host range; potential vector of encephalitis, dog HW, dengue, yellow fever, container breeder, persistent biter, flight range 200yds
brought in via old tires that had water in them
asian tiger mosquito
what information does trapping give you
what species are active, infection rate, identify blood meals
heartworm form
small, slender, unsegmented round worms
stages of heartworm
microfilaria, L1, L2, L3, L4, Adult
filariasis
heartworm disease is caused by thread-like parasitic namatodes that attack >30 species
consequence of heart worm
build of in heart and large vessels of the lungs - prevent valve closure - can lead to heart failure and death
symptoms of heart worm
early infection: difficulty breathing
mild disease: cough
moderate disease: exercise intolerance, abnormal lung sounds
severe disease: difficulty breathing, enlarged liver, loss of consciousness, fluid in abdomen, abnormal heart sounds, death
male vs female HW’s and life expectancy
Male 4-6 in female 10-12 in
full grown in 1 yr; live 5-7 yrs
vector of hw
mosquito is biological vector –> disease occurs in host, host gives it a place to develop; where sexual stage of nematodes occur
hw life cycle
microfilariae ingested by feeding female mosquitoes
after 2 molts, infective third stage larvae (L3s) are present i mosquito mouthparts adn deposited on the skin of the dog during feeding and migrate through the bite wound into the host
most L3s molt to 4th stage in subcutaneous tissues within 1-3 days after infection
how long does it take for canine host to demonstrate microfilaremia after infection
6-7 months
the highest rates of infection occured where in the US
near water - coast and mississippi river
mosquito vector species
70 competent vector species
24 naturally infected
asian tiger mosquito in SE container breeder; feeds on a variety of vectors
protection and cure for HW
protection from mosquitos
repellent
hw prevention meds
treatment for hw
3 injections of an adulticide deep into muscle - painful and stressful to animal
dying worms can cause foreign bodies in body; shock
best way to protect pet from HW
prevention
gravid trap
attracts females to lay their eggs dirty water in bucket females go up in net
CDC Co2 trap
co2 used as bait; light; fan also
artificial container/tree hole
keep thick paper wet to get mosquitoes to lay eggs in it
negatively phototactic
instinct is to move away from light
