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NC Ticks: the Common Species, their Biology, Behavior, and Medical Importance
This presentation is presented by: Minor Barnette, NCSWEOA 10/22/2015
(Created by: Bruce A. Harrison, PhDTaxonomist/Public Health Entomologist
Clemmons, NC )Thank you Dr. Harrison!
Questing behavior
Lone Star Tick
Proper tick removal
Avoiding Ticks• Avoid activity in tick infested areas. • Stay on paths, avoid brush and tall grass.• Wear light colored clothing so ticks are easier to
spot.• Wear long pants and long sleeved shirt. Tuck
pant cuffs into socks or boots; tuck shirt-tails into pants.
• Use repellents. Permethrin is most effective against ticks. Follow label directions.
• Check frequently for ticks on clothing and skin. • Remove attached ticks quickly.
Avoiding ticks
Ticks have evolved along with and are primarily parasites of various wildlife host species.
Tick stages = egg, larva, nymph, and adult. The last three stages require a blood meal to complete their life cycle.
• Growth = by shedding skin (molts) between stages.
• Reproduction = oviposition of fertilized eggs.
Humans are incidental hosts for ticks.
Tick life cycle
Common wildlife hosts of ticks in NCAmerican dog tick (Dermacentor variabilis)
larvae and nymphs
vole white-footedmouse
adults
dograccoon
Lone Star tick (Amblyomma americanum)
dograccoonbirds deergray squirrel
larvae, nymphs and adults (except birds)
larvae and nymphs adults
birds w-f mouse
Black-legged tick (Ixodes scapularis)
skink dog deer
X
Why are ticks efficient vectors?
• Environmentally tolerant.• Each stage may feed on a different host, or the
same host.• Feed on a variety of wildlife species.• Feed for a long period of time.• Consume a large volume of blood.• Long-lived.• Often transmit pathogens transovarially.
Tick bites occasionally result in transmission of pathogens.
For Lyme disease, the erythema migrans rash occurs at the site of the tick bite.
For RMSF, the rash occurs on the wrists and ankles, palms and soles, and spreads to the trunk of the body.
Ticks and Disease in NC
• Lyme disease (Borrelia burgdorferi s.s.)
• Southern tick associated rash illness (STARI) ?• Spotted fevers (Rickettsia rickettsii, parkeri, etc.)
• Ehrlichiosis (Ehrlichia chaffeensis, ewingi, etc.)
• Anaplasmosis (Anaplasma phagocytophilum)
• Tick paralysis (caused by a tick neurotoxin)
Ticks Commonly Found in North Carolina
• Dermacentor variabilis - American dog tick, only adults on people. Common throughout the state.
• Amblyomma americanum - Lone star tick, adults, nymphs and larvae on people. Most common in eastern 1/2 of the state. Range is spreading.
• Ixodes scapularis - Black-legged tick, only adults on people. Nymphs rarely on people in the south. State wide, but most common in Coastal Plain counties.
• Rhipicephalus sanguineus - Brown dog tick, common on dogs, rarely on people. Widespread but less common since new topical treatments on dogs.
Identification: Short mouthparts, festoons,
white markings
Distribution: Throughout North Carolina
Vector of: Spotted fevers, Tularemia, Ehrlichiosis, tick paralysis
Female Male
Larva Nymphshortmouthparts
festoons
Dermacentor variabilis
American Dog Tick
whitemarkings
53
Early symptoms of RMSF and related rickettsial infections
• Patients usually much sicker than with Lyme/STARI
• Higher fever• Bad headache• Shaking chills• Muscle aches• Often no rash• MUST BE TREATED PROMPTLY ON
SUSPICION• After 6 days, if left untreated, there
is a 25% or higher mortality rate
Black-legged tick(= Ix. scapularis)
Identification: Long mouthparts, black legs,
red color, no festoons
Distribution: In North Carolina primarily in the coastal plain and piedmont counties
Vector of: Lyme, Anaplasmosis, Babesiosis
Female Male
Nymph
no festoons
black legs
long mouthparts
54
Larva NymphM adult F adult
Black-legged tick, the primary vector of Lyme Disease(= Ixodes scapularis)
Note Small size of Nymphs 7
Rash Examples- STARI and Lyme Disease
Multiple lone star tick larval biteswww.tic-nc.org
Erythema migrans:STARI
Erythema migrans: Lyme disease (Master’s NY-MO)
Lyme disease
Lone star tick
Identification: Long mouthparts, round shape
females with white spot, festoons
Distribution: Exceptionally common throughout coastal plain and eastern piedmont, less common in western NC
Vector of: Ehrlichiosis, STARI, tick paralysis, ? Lyme disease
Female Male
Nymph
“lone star” spot
round shape
white markings along festoons
long mouthparts
52
Lone Star TickAmblyomma americanum
Lone Star tick is the most important nuisance species in NC.
• Most abundant tick species in the southeastern US.
• All stages readily attack humans.
Rhipicephalus sanguineus
Brown dog tick
IdentificatioIdentification:n:
Short mouthparts, festoonsShort mouthparts, festoons
no white markingsno white markings
Distribution:Distribution: Throughout North CarolinaThroughout North Carolina
can reproduce indoorscan reproduce indoors
VectorVector of:of: RMSF, dog pathogens, othersRMSF, dog pathogens, others
Male
Female
LarvaEngorged tick
festoons
short mouthparts
55
Typical peridomestic environment surrounding case-patient homes, found to be heavily populated by Rh. sanguineus ticks
Environmental Assessment
Rocky Mountain spotted fever
View from belowView from above