Ectoparasites management + control

Página 1

Ectoparasite management + control

Describe how life cycles, behaviour and seasonality influences need for and approaches to management control

Management control

Low challenge - well tolerated

High challenge

E.g. summer, housed stock

Poor condition

Weight loss

Morbity

Mortality

Control techniques

Treat at turn out

Environemental control

Hygiene and management

Dagging

Removal of contaminated fleece

Barriers and protection

Sticky tapes

Pheromone + sugar baits

Owner

Bites

Zoonoses

Vectors

Describe basic types of preparations, delivery systems and advances in targeted control

Chemical control

Skin contact

Pour ons

Spot ons

Ear tags

Collars

Systemic

Chewable tablets

Injectables

List the major classes and give examples in each class their modes of action, target arthropods

Safe use and contraindictations

Organophospates

DDT

Insecticide discovered in 1939

Use againstHigher human lice + mosqitoes = WWII

Used in malaria eradication programme

Widespread resistance in mosquitoes

BANNED USA +UK - environmental impact

Diazinon

Bind to acetylcholinesterase , leads to build up of acetyl choline

Continued biding = paraylsis

Phased out for domestic use

Licensed as sheep dip

Cont blowfly , lice + mites 70d

High toxicity to humans - novichock

Synthetic pyrethroids

Natural

Repellency / rapid kill

Not residual

Low mamalian toxicity

Excite cell membranes

Depolarise Na and paraylsis

Synthesised

Photosable

Higher potency

Broad spectrum

Enhanced -PBO

Acts faster

E..g. Permethrin Cypermethrin

Non systemic

Topical!

Macrocyclic lactones (MLs)

Examples: Avermectins, Ivermectins, Doramectin, Selamectin, Eprinomectin, Abamectin, Milbemycins, Moxidectin, Milbemycin oxime

Endectocides

Arthropods and nematodes!

V broad spectrum of activity in arthropods

Variable

Active molecules

Method of activation

Stimulate GABA release form nerve endings

Inc flow of Cl ions = hyperpolarization

Flacid paraylsis

Mammals - GABA cant cross BBB = wide safety

NB collies sensitive to ivermectin!

Systemic and Topical

Highly lipophillic!

Systemic sow release (storage in fat)

Extended protection

Withdrawal periods

Insect growth regulators

Chitin inhibitors

Examples

Cyromazine , protects against blowfly 14w

Diflubenzuron, lufenuron , eggs fleas non viable , larval stages

Juvenile hormone analogues

E.g. methoprene, keeps fleas young

Imidacloprid

(Neonicotinoid)

Binds to nicotinic ACH receptors in the insects CNS

Paralysis

Death

Negative impacts on honeybee populations

Restrict agricultural use

Use in companion animals

Flea adulticide

Not affective against ticks

Fironil

Blocks GABA transmitter in fleas + ticks

V lipophillic

Reservoir in hair follicle galns

Toxic to fish + bees

Used in companion animals

Amitraz

Octopamine receptor sites

Ticks of cattle + dogs

Burrowing mites of dog

Contraindication = Horses + Cats

Isoxazolines

Systemic

Rapid absorption

Afoxolaner + Fluralaner

GABA/glutamate receptors on ion chloride channel

Ticks and fleas = Treatment + prevention

Fleas within 8hr

Ticks within 48hrs

1m

Lotilaner

Adult flea death within 2hr

Efficient against re infestation + reduced flea allergic dermatisis

Ticks killed within 12h

Prevents some tick borne infection