Ticks Flashcards
tick paralysis
block Ca2+ in nervous system that causes paresis
general tick characteristics
fused 2 piece body plan
-fused head/ thorax
-abdomen
(no constriction between head and body)
Chitinous exoskeleton w hard scutum (dorsal shield)
Toothed hypostome to embed in host
ADULT & NYMPH 8 legs
LARVAE 6 legs
ALL STAGES PARASITIC AND ALL SUCK BLOOD
1 host
uses 1 host for entire lifecycle
molt occurs on host
eggs deposited off host
susceptible to control efforts
-Transovarial disease transmission
2 host
uses2 host to complete lifecycle
Larvae/nymph feed on same host
adults acquire new host to complete lifecycle
eggs off host
-interstadial disease transmission
3 host
uses 3 hosts to complete lifecycle
-leaves to develop, could go back. doesn’t require different host species
eggs off host
-interstadial disease transmission
**common for ticks in US
transovarial transmission
infectious agent passed to progeny through ovaries
only mechanism for one host ticks to vector disease
interstadial transmission
infectious agent acquired by larvae/nymph from host and passed to successive stages
ixodes scapularis associated with
Lyme disease
amblyomma americanum associated with
STARI
Ehrlichiosis
dermacentor varriabilis associated with
rocky mountain spotted fever
what characteristics to look at to tell tick species apart
capitulum
scutum
festons
spiracles (ventral)
anal groove (ventral)
Dermacentor
short mouthparts
host seeking tick
d. varriabilis
american dog tick
3 host lifecycle
adults on large vertebrae
—RMSF, Q fever, tick paralysis
rocky moutain spotted fever
acute disease associated w rickettsial infection by d. varriabilis
non-specific muscle aches and fever initially
rash 2-5 days post tick exposure
**April-September
easily treated w antibiotics, early diagnosis is key
tick paralysis
associated w neurotoxic salivary component
rapid ascending paresis-> respiratory failure and fatal
can be caused by single tick
associated w d. varriablis
ZOONOTIC
Amblyomma americanum
Lonestar tick
long mouthparts
prominent white spot on dorsal scutum
festoons along distal margin
host seeking, 3 host tick
STARI
southern tick associated rash illness
associated w lone star tick
matches w Lyme disease timing
ehrlichiosis
acute disease of human and animals
gram neg bacteria invade white blood cells
low white blood cell count/ platelets
principle vector= ambylomma americanun
rhipcephalus sanguineus
brown dog tick
3 host life cycle
tropical distribution
-adapted to living indoors
-central heating offers optimal temp and humidity
rapid lifecycle= huge populations (short as 2 months)
LATERAL EXPANSION
disease vector for RMSF, hepatozoon canis, b. gibsoni
haemaphysalis longicornus
longhorn tick
invasive 3 host tick species
significant vector potential MANY (ehrlichiosis)
reproduce pathenogenically, males rare b/c unnecessary
REPORTABLE TO STATE VET/ USDA
**expansion of mouthparts on 2nd ridge of palpi
severe fever w thrombocytopenia syndrome
anorexia, weight loss, fever
more severe in BIG cats
dogs not as susceptible
-clinical signs but not fatal
-resolve without treatment
ixodes scapularis
black legged deer tick
host seeking
**LYME DISEASE
3 host life cycle
small w long mouthparts
black scutum and legs
no festoons
are ixodes scapularis born with Lyme disease
NO
no transovarial transmission
ixodes scapularis disease transmission cycle ?
ticks feed as larvae in summer/fall
-infected w borrelia burgdorferi
-transmitted to humans in the following spring
*Small size allows for prolonged feeding
Lyme disease
reactive arthritis
-irregular/ slow heartbeat
flu-like illness
early diagnosis and treatment w tetracycline
rhipicephalus annulatus & R. microplus
1 host life cycle
vector of texas cattle fever
R. microplus related to wild ungulates/horses
**persistent cases may facilitate spread and reintroduction of TCF w/ climate change
ridged palpi !
reportable disease
why are nymphs associated with efficient transmission of infectious disease? ***
Can be infected trans-stadially and then infect other hosts
why is feeding time regarded important for successful transmission of an infectious agent vectored by 3-host tick? ***
smaller tick stages feed longer without being noticed, so have greater potential to transmit
soft tick general morphology
leathery body
head not visible from above, underneath
feed via vampire model
lay eggs in small batches multiple times
vampire model
feed @ night when hosts sleep
argas
poultry tick
3 host, all stages parasitic
adults rarely seen bc vampire model feeding
transmit avian spirochetosis and tick paralysis
all stages withstand starvation up to 2 years
ornithodoros
avian, rodent, deer, & cattle
larvae do not feed
Nymph requires blood meal for each molt (M=4 F=5)
adults rarely seen bc vampire model feeding
all stages withstand starvation
transmission of borreliosis
otobius
spinose ear tick
cattle, horse, livestock
pawing at ears
1 host life cycle
ONLY LARVAE & NYMPHS PARASITIC !!
adults w vestigial mouthparts do not feed, females lay one clutch of eggs
preventing tickborne diseases
limit tick exposure activities
wear light clothing
use repellents
body check
infectious disease transmission function of duration of tick feed
–timely removal is key
