Control of Ticks on Livestock Flashcards
what are paralysis ticks
Salivary neurotoxins that are variably reversible cause progressive paralysis
Ixodes holocyclus toxin is similar to botulinum toxin
Karoo paralysis tick Ixodes rubicundus (Southern Africa)
Paralysis tick Ixodes holocyclus (Southeastern Australia)
American dog tick Dermacentor variabilis (USA)
Rocky Mountain wood tick Dermacentor andersoni (USA)
what diseases do ixodes ricinus cause
Babesia divergens
Anaplasma phagocytophilum
Staphylococcus aureus tick pyemia
Louping ill virus
Diverse rickettsiae
what dieseases do dermacentor reticulatus cause
Babesia spp
Anaplasma marginale
what diseases do Haemaphysalis longicornis cause (autralasia and asia pacific)
Theleria buffeli/orientalis and others
what diseases do Rhipicephalus microplus (Australasia & Asia Pacific)
Babesia bigemina
B bovis
A marginale
what diseases do Rhipicephalus microplus & R decoloratus (africa) cause
Babesia bigemina
B bovis
A marginale
what diseases do Amblyomma variegatum & A herbraeum cause (africa)
Ehrlichia rumination known as heartwater
what disease does
Rhipicephalus appendiculatus
cause
Theileria parva East-Coast-Fever (ECF)
how many hosts does I ricinus have and how long is the life cycle
3 host tick with 3 year life cycle
Hosts:
Larvae on small mammals, birds
Nymphs on rabbits
Adults on ruminants
what environmental conditions do I ricinus need
Need >90% humidity
Questing when >10ºC
Feeding activity peaks April & May in most of UK
In high rainfall areas there is feeding also in Aug and Nov
what is the most important species of tick globally
r microplus
what is R microplus distribution limited by
mean temp
need <4 months <16C and rainfall
what is the lifecycle of R microplus
1 host tick
18-35 days on single host
Range of total LC 42-300 days
3-5 generations per year
Host include cattle, horses, small ruminants, wild ungulates
what are the impacts of ecology of r microplus
Simple life cycle
Strategic control programmes relatively simple
High fecundity — potential for rapid and massive infestation
Single host lifecycle with potentially low refugia accelerates acaricide resistance
what are the impacts of ticks
TBD transmission
Reduced growth rates
Reduced production
Anemia
Tick worry pyoderma
Hide damage
what does host density have to do with tick control
No host no ticks
The extent to which wildlife hosts can maintain tick populations varies among species
Re-stocking after periods with few or no cattle will increase tick problems
what does host resistance have to do with control
Some breeds more resistant than others
what does temperature have to do with tick control
Low temperatures retard growth but don’t kill ticks unless temperatures are extreme
High temps shorten survival but accelerate development
Very high temperatures and low humidity are lethal to ticks
what does humidity have to do with tick control
Desiccation and inundation can both be lethal to ticks
Ticks will survive flooding and are dispersed widely by floods
Desiccation effects on the stage affected
what does vegetation have to do with tick control
Ticks make use of vegetation to find their hosts and also to protect themselves from direct sun
In the absence of vegetation, survival times of larvae are much reduced
what are the eradication requirements
- Continuously treat all possible hosts for the maximum period that free-living ticks can survive at intervals that are less than the minimum parasitic phase
* ex. R. microplus this means 6-8 treatments every 3 weeks during early summer - Strong legislation
- Full or regional compliance
- Effective acaricide
- Effective methods of application
what are the pros and cons of eradication
Pros: ends needs for treatment
Cons: rarely successful, if fails likely to increase resistance to acaricides, if successful, population susceptible to TBDs
what is reactive vs strategic control
Strategic control is sometimes confused by farmers and advisers with reactive, suppressive control or threshold control
A “suppressive” or “reactive approach” might be expected to result in farmers applying treatments at times corresponding with the yellow arrows
“Strategic” approach treatments are applied at predetermined times to maximize their impact on the total population of ticks on any given area of land
what are the major acaricide groups
Arsenic
Organochlorines (OC)
Organophosphorus (OP)
Carbamates
Synthetic pyrethroids (SP)
Macrocyclic lactones (ML)
Amidines
Insect acarine growth regulators
Phenylpyrazoles
what are organochlorides
interfere with nerve conduction (na ion channels)
effective on contact
toxicity & environmental concerns
widespread resistance
what are organophosphates
Esters of phosphoric acid
Bind AChE (responsible for breakdown of ACh)
Effective on contact
Still used in UK and USA
Human toxicity
Widespread resistance
what are synthetic pyrethroids
Cypermethrin, flumethrin, permethrin
Esters of chrysanthemum acid
Depolarize axonal Na channels
Excitation then paralysis
Stable in field
Good against flies
Main products used in UK
Important hazard to aquatic life
Widespread resistance
Significant environmental impacts
what are amidines
Amitraz, cymiazol
Effective on contact
Less effective on flies
Act on octopamine receptor
Important effect is detachment
Fewer toxicity and residue concerns
Biodegradable
Not available in Europe
Resistance common
what are macrocyclic lactones
Ivermectin, moxidectin
Effective on ingestion
Widest range of target species
Concerns re aquatic and terrestrial arthropods
GABA agonists
Irreversible blockade of nerve transmission
Mainly for single host ticks
Broad spectrum — off target effects
Expensive
Don’t prevent TBD transmission
Resistance confirmed in Latin America
Known adverse effects on dung-associated arthropods
what are acarine growth regulators
Fluazuron
Inhibit progression through stages
Single host species mainly
Don’t prevent transmission of TBDs
Problems with lactating cows — long withholding periods
Resistance confirmed in Latin America and Australia
what are phenylpyrazoles
GABA-gated and glutamate-gated chloride channel blockade
Also effective on insects
Few products
Resistance widespread in Latin America
what are the application methods
pour on
hand spray
spray race
plunge dip
what are the pros and cons of pour on application
Expensive
Persistant
Easy application
what are the pros and cons of hand spray application
Cheap
Not for eradication
Can fail due to incomplete coverage
Workplace health and safety issues
what are the pros and cons of spray race application
Expensive
High maintenance requirement
Design is critical
what are the pros and cons of plunge dip application
Theoretical best method but
Volume not certain — dilutions incorrect
Dilution by rain
Concentration by evaporation
Inadequate mixing
Cattle not effectively plunged
Inadequate stabilization
Acaricide resistance
are there effective tick vaccines
Cattle vaccinated against tick-gut glycoproteins
Ticks suck blood with antibodies
Tick gut damaged and leaks
Don’t reproduce well
Some die
Mainly for R. microplus
New vaccine rages are being explored
what are tick biopesticides
Not commercially available yet
Fungus (Metarhizium anisopliae) attacks tick
Applied by spray
