Acarina - Ticks Flashcards
Give the kingdom, phylum, class, order and family of ticks
Animalia Arthropoda Arachnida Acarina – ticks and mites Argasidae (soft ticks) & Ixodidae (hard ticks)
4 facts about soft ticks that differ from hard ticks
1) No plate on back
2) Indistinguishable life stages
3) Multiple nymphal stages
3) Usually nest or burrows
4) Many short feedings
4 facts about hard ticks that differ from soft ticks
1) Hard plate (scutum) on back
2) 3 distinct life stages – egg, larva, nymph
3) Mostly not nests or burrows
4) Few long feedings
What type of metamorphosis do ticks go through? What are the stages?
How long is it off of a host (%)?
Gradual metamorphosis egg 6-legged larva 8 legged nymph adult >95% off of host
Ticks have high _____ which offsets low _____.
1) High fecundity offsets low survival
2) Thousands of eggs/ female
3) Very few survive to adult
How do ticks survive? (5)
1) Endure long periods off the host with limited energy & water and ability to move
2) Find shelter from direct sun – dead grass and leaves, soil cracks
3) Absorb water from air (mouthparts)
4) Find host and mate
5) Need proper temperature – rainfall - protection
Where can you find ticks?
Overgrown areas
Tall grass
Near where they drop off of host
How do questing ticks find hosts? (6)
1) CO2
2) Vibration
3) Body heat
4) Host-produced substances – sweat and skin lipids – host specificity
5) Vision
6) Sensory disc on palp
How do ticks attach? (3)
How long do they need to be attached for disease to transfer?
1) They usually wander before settling
2) Cut skin and anchor with “cement”
3) Saliva prevents blood clots, dilates capillaries
* 24 h – 36 h attachment for disease transfer
When do ticks detach and drop? (3)
1) Engorged ticks should drop in optimum habitats
2) Associated with host behavior
3) Usually when hosts are inactive – after nightfall or during day for nocturnally active hosts
6 ways that ticks impact their hosts?
1) Parasites – blood feeders
2) Cause stress to host – irritation, anemia
3) Allergic reactions to injected substances
4) Feeding wounds - maggot attack, secondary infections
5) Transfer pathogens (vectors) 2nd to mosquitoes
6) Tick paralysis
What are the 4 common KY ticks?
1) Black legged tick – limited distribution in KY
2) Widespread - American Dog tick & Lone Star tick
3) Brown dog tick - rare; limited to sheltered areas, kennels
1 host tick is also the _____ tick.
Describe when larva –> adult feed
Winter
Larva - Feed in Nov, molt
Nymph - Dormant 2 months, feed in Jan and molt
Adult - Feeds Feb - Mar, when host is most stressed.
What are typical hosts of 1-host ticks?
Hooved animals: elk, deer, horses, moose
Where do 1-host ticks quest? When?
Quest on vegetation at chest height (mid-Sept to early Oct)
What are the symptoms of a 1-host tick host?
Blood loss, hair loss from scratching, less feeding
Name three 3-host ticks
1) American dog tick
2) Lone star tick
3) Blacklegged tick
American dog tick larvae only feed on _____.
Small mammals
Lone star tick larvae feed on _____.
All size hosts
Blacklegged tick larvae feed on _____ - differences in _____ incidence.
All size hosts
Lyme disease incidence
Blacklegged tick - genus and species. Where are they found?
Ixodes scapularis
Eastern & south, & north central US
Larvae & Nymphs of blacklegged ticks feed on mostly small mammals in north, *_____ in south
Skinks
BLT main host is _____.
Main host is white-tailed deer
Brown dog tick - genus and species – can become established _____.
Rhipicephalus sanguineus
Indoors
What does zoonosis mean?
Disease that can be transmitted to humans from animals.
What does enzootic mean?
Disease that regularly affects animals in a particular district or at a particular season.
What does epizootic mean?
Disease that is temporarily prevalent and widespread in an animal population.
Arthropod-borne diseases:
Vector transmits pathogens and parasites from one infected _____ to another.
Not all species are _____
Not all competent individuals are _____ (_____%)
Person/host
Competent
Infected (1%)
Name 3 important vector groups
1) Mosquitoes & flies
2) Ticks
3) Fleas
Two types of transmission
Mechanical and biological
Describe mechanical transmission
Carry physically on body OR interrupted feeding – no development
Like a machine/vectors are not infected, they merely pass on the pathogen (carriers)
Describe biological transmission
Vector will develop pathogen
Ex: Dog heartworm in mosquito
Adaptations of host, vector, & pathogen (4)
1) Vector feeds on “right” host
2) Feeds at time to pick up pathogen
3) Feeds in a way to pick up the pathogen
4) Pathogen can get into new host – penetrate vector gut wall, move to salivary glands, etc.
Competent vectors: no perfect vectors – have some combination of characteristics (8)
1) Acquire, maintain, and transmit pathogens
2) Provide suitable internal environment
3) Live for some minimum time
4) Feeding pattern matches pathogen host range
5) Feed often for extended periods
6) Ingest large amounts of blood
7) Be able to disperse
8) Primary vs secondary vectors
5 factors involved in incriminating a vector (IDing a vector - used by scientists, doctors, etc.)
1) It must be competent
2) Geographic pattern must match the disease
3) Must be abundant
4) Must feed on reservoir and host
5) Must live for some time
Infected vectors usually about _____% of population
1%
Texas cattle fever is also called _____
“Redwater” fever
Redwater fever:
_____ cattle affected after _____ cattle passed through.
Northern affected after Southern passed
Within about 10 miles of drive trail
4 symptoms of redwater fever. % dead in a week?
1) Red urine (hemoglobin)
2) High fever
3) Loss of appetite
4) Respiratory distress
95% dead in a week
Redwater fever’s cause
Cause unknown
1868 Outbreak- 15,000 _____ cattle died after being mixed with _____ cattle
_____ not necessary. Why?
Cattlemen suspected ticks, toxic plants, other ideas
Illinois died after mix with Texas
Direct contact was not necessary; northern cattle on pasture used by southern cattle got sick
Solution 1 for Redwater fever
1) Move southern cattle north only during fall or winter OR 2) Winter cattle on isolated pasture– finish in spring
No Texas fever outbreaks in northern cattle
Problems with solution 1
1) Shortage of winter pasture
2) Need winter base and cowboys
3) Southern cattle had high winter losses
4) Rustlers
5) Reduced profits $
Solution 2 for Redwater fever
Established a cattle trail that was 20mi wide in order to split the northern and southern cattle.
Loss of land and water, $$, labor, etc.
Main source of lyme disease pathogen =
White footed mice
In cyclodevelopmental biological transmission, the pathogen…
Develops in vector
In propagative biological transmission, the pathogen…
Multiplies
In cyclopropagative biological transmission…
Both develop and multiply
Solution 3 to Redwater Fever
Kansas closed their cattle trail - caused violence
1880’s Koch and Pasteur identified
germ theory
4 criteria to identify causative agent of a disease (Koch’s Postulates)
- ) Isolate diseased cow
- ) Remove suspected pathogen from cow and place in pure culture
- ) Allow to grow and introduce it to uninfected, unexposed cow.
- ) Compare results
1893 - Smith isolated protozoa from cattle blood that _____
Destroyed RBCs - found in blood of all infected cattle
3 steps on how they determined how disease was transferring
- ) Remove ticks from southern cattle and then mix southern and northern cattle - all healthy
- ) Scatter ticks from southern cattle and add northern cattle - northern got sick and died
- ) Hatch ticks from eggs in lab - place on northern cattle - they died
Type of transmission from eggs
Transovarial transmission
Offspring of infected ticks could transmit the disease without feeding on infected cattle
Texas Cattle Fever Babesia lifecycle - type of disease and the hosts
Malaria-like parasitic disease
Hosts - ticks and cattle
Babesia develops in…
Cattle blood cells and destroys them (asexual production)
Sexual production in tick ovaries
Babesia to egg and salivary glands (sexual reproduction)
Babesia pathogen and Boophilus ticks on cattle and horses brought by _____
Spaniard colonists
Boophilus is a _____ tick
1-host
Boophilus has a _____ long feeding stage - larva to adult, mating, final meal off host - females lay eggs _____ to hatch. This has an impact on ?
18-20 day long
30-270 day to hatch
Impact on controlling with chemicals
Method of tick control
Dip cattle in oil, later arsenic (Arsenic kills cattle, small animals, plants). Use a [ ] strong enough to kill ticks only
Oil blocks breathing tube
7 tick control practices
1) Brush management
2) Self-treatment devices for deer
3) Neck band applicator
4) Wildlife management plan
5) Prescribed burning - once every 3 years
6) Resistance - select for ticks that can survive chemical
7) Cattle dip - acaracide every 14 days - dip before feeding complete
6 potential reasons for TCF resurgence 2007-2008
1) Reduced funding - fewer tick riders
2) Less dipping - more pasture “resting”
3) Cancelled products - acaracide-resistant ticks
4) Increased populations of secondary hosts white-tailed deer, nigal antelope
5) Increased rain and milder winters > tick survival
6) Reduced tick management in Mexico
LST nuisance. 4 reasons
1) Tick bite allergies - reactions to saliva, vasodilators, anticoagulants, other proteins
2) Often localized inflammation
3) Lasts 10 days or more
4) Sensitizes some people
Primary vector of erlichiosis
Lone star tick
Several bacterial diseases that affect humans and animals describes what?
Erlichiosis
Symptoms of erlichiosis
Headache, fever, muscle aches within 1-2 weeks of bite
Two viruses of erlichiosis
Heartland and Bourbon viruses
Suspected cause of ticks and red meat allergy
Antibodies to sugar produced in person’s blood after multiple LST bites
Ticks and red meat allergy - how long is delay in rxn and when does it subside
3-5 hr delay in reaction - hives
Subsides in 3-5 years
Which tick is a vector of lyme disease?
BLT
What animal is main disperser of BLTs?
Deer
Nesting treatments for BLTs
Pesticide-treated cotton balls –> Nesting material –> Ticks on mice are killed
3 ways of managing ticks
1) Clearing brush - habitat management
2) Reduce immigration - ticks have limited movement but hosts can carry them long distances
3) Acaricide applications - usually not practical
Why do winter tick larvae occur in such large groups?
Larvae hatch from masses laid on the ground that can contain up to 3,000 eggs. They do not disperse far but climb nearby vegetation to wait for passing hosts.
How is global warming affecting the winter tick population?
When females drop to ground they lay their eggs. The rate at which this occurs depends on temperature.
If the females fall onto snow, survival (to the point where they lay eggs) is poor. If they fall onto bare forest floor, many more survive.
