Maureen Brophy MPH PhD Student Outline What are ticks Biology Ecology Disease transmission Rocky Mountain spotted fever What is a tick Arachnids not insects Related to spiders External parasites of mammals birds and reptiles ID: 776127
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Slide1
Ticks and Their Diseases
Maureen Brophy, MPHPh.D. Student
Slide2Outline
What are ticks?BiologyEcologyDisease transmissionRocky Mountain spotted fever
Slide3What is a tick?
Arachnids, not insects
Related to spiders
External parasites of mammals, birds, and reptiles
>800 species describes worldwide
~80 species in the U.S.
Leading disease carriers in United States
Second to mosquitoes worldwide
Slide4Arthropods That Feed on Vertebrate Blood
Slide5How to Spot a Tick
Very small, but bigger after meal8 legs*Mostly oval*Except larvae
Slide6Hard vs. Soft Ticks
Ixodid = hard ticksArgasid = soft ticks
Slide7Life Cycle
Slide8How to Ticks Find Hosts?
Questing
Step 1- Find grass, bush, twig, etc.Step 2- Climb to top of itStep 3- Extend forelegsStep 4- WaitStep 5- Latch onto passing host
Hunting
Step 1- Sense hostStep 2- Chase hostStep 3- Catch host
Slide9Biology
Slide10External Anatomy
Slide11External Anatomy
Body
Top side- scutumFemales have “shield”Allows for body to grow during feedingCan grow many times original size after feeding
Slide12External Anatomy
“Head”/mouth area
Basis capitulum
Slide13External Anatomy
MouthpartsHypostomeCheliceraePalps
Slide14Slide15Saliva
Excrete concrete-like saliva into wound, create feeding tubeContains anesthetic, anti-coagulants, immunosuppressants, vasodilatorsAlso helps with water regulation
Slide16External Anatomy
Legs
3 pair (6 legs) as larva4 pair (8 legs) as nymph and adultGood for grabbing and climbing
Slide17External Anatomy
Sensory
“Hairs” on legs and body sense vibrationHaller’s organ “smells” chemical cues from hostBasic eyes
Slide18Internal Anatomy
Diverticulated gutSalivary glands grow during feedingMalpighian tubule helps absorb nutrients
Slide19Blood Feeding Requirements
Sensory apparatus to locate vertebrate hostSpecialized piercing-sucking mouthpartsSaliva components to prevent blood coagulation and host immune responseCapacity to deal with dramatic increase in gut volume
Slide20Number of Hosts
Depends on tick species
Slide21Ecology
Slide22Where Do Ticks Live?
Depends on type of tick
Dog ticks- near home, wherever they can find dogs
Soft ticks- in nests, caves, where they can find birds, bats, rodents
Other ticks (
Dermacentor,
Amblyomma
)- In wooded areas, scrub, where they can find rodents and larger mammals
Slide23Peridomestic Environment
Dog ticks live close to home
Items in yard (old furniture, toys, appliances, trash) can provide shelter and breeding sites for ticks
Where the dogs go, the ticks go
Slide24Ticks on Navajo Nation
Ixodid
Rhipicephalus sanguineus
Dermacentor andersoni
Argasid
Ornithodoros
species
Slide25Slide26Slide27Disease Transmission
Slide28364D rickettsiosis
Alpha-gal
Anaplasmosis
Babesiosis
Borrelia
mayonii
Ehrlichiosis
Tickborne relapsing fever (TBRF)
STARI (Southern tick-associated rash illness)
Rocky Mountain spotted fever (RMSF)
Tularemia
Rickettsia parkeri rickettsiosis
Borrelia miyamotoi
Bourbon virus
Colorado tick fever
Heartland virus
Lyme disease
Powassan disease
Granulocytic
Anaplasmosis
Slide29How Do Ticks Get Infected?
Horizontal Transmission- pathogen is acquired from a host, develops or multiplies in tick, and is transmitted to next host
Vertical Transmission- female lays infected eggs, ticks can infect in larval form
Slide30Tick-borne Diseases in Arizona
Rocky Mountain spotted fever
Ehrlichia
canis
Tularemia
Tickborne relapsing fever
Slide31Rocky Mountain Spotted Fever
Slide32Disease Cycles
Slide33Distribution
2014 Incidence Map: CDC
Slide34Distribution
In Arizona, brown dog tick is vector (
Dermacentor
ticks in other parts of the country)
Higher case fatality rate
Slide35Symptoms
FeverHeadacheRashNausea & vomitingStomach painMuscle painLack of appetiteCan be deadly if left untreatedMost common in young children
Slide36Risk Factors
Roaming dogs
Dogs not spayed/neutered
Clutter in yard
Dogs can get RMSF too
Dogs CANNOT give humans RMSF
Slide37Prevention
Check for ticks
Remove ticks immediately if found
Reduce yard clutter
Apply tick collar or topical pesticide on dogs
Use environmental pesticide (properly) if there is a tick infestation
Slide38Prevention
Slide39Treatment
Doxycycline ASAP
If you have RMSF symptoms and (might have had) exposure to ticks, seek medical care (and tell them to test for RMSF)
Doxycycline is safe and does not stain children’s teeth
Slide40Maureen Brophy
PhD Student
University of Arizona
Brophymk@email.arizona.edu