Ectoparasiticides Flashcards
Why should ectoparasites be controlled?
Pet health (welfare, damage) Owner health (dermatitis, bites, zoonoses)
What are 3 broad ways to control ectoparasites?
Broad spectrum ectoparasiticides
Integrated pest mangement (IPM)
Non-chemical use
How can broad spectrum ectoparasiticides be administered?
Parenteral - SC/IM
Oral
Topical - pour on, spot on, tags, collars
What is done for integrated pest management (IPM)?
Hygiene and management of breeding sites
Vacuuming/washing bedding
Removing ticks
Dagging/crutching (remove dirty wool from around anus)
What are examples of non-chemical use for ectoparasite control?
Protection of teats Rugs (stripes) Sticky tapes Pheromones Sugar baits
What are the 6 main classes of broad spectrum ectoparasiticides?
Organochlorides Organophosphates Synthetic pyrethroids Macrocyclic lactones Insect growth regulators Isoxazolines
Which class of ectoparsiticide is now banned and why?
Organochlorides
Enivornmental impact
How do organophosphates work? What are they only used for now?
Bind to acetylcholinesterase
Build up of ACh = paralysis
Sheep dip
What is a disadvantage of organophosphates? Give an example of an OP
High toxicity to humans
Diazinon
How do synthetic pyrethroids work?
Excite cell membranes
Causes depolarisation and paralysis
What are the advantages of SPs?
Rapid kill - not residual
Low mammalian toxicity
How are SPs administered? Give 2 examples
Topical - skin
Permethrin, cypermethrin
Which SP should not be given to cats and why
Permethrin = toxic to cats
Macrocyclic lactones are used for both eco and exoparsites. What are the 2 groups and give an advantage of each. What breed is sensitive to one of these?
Avermectin - e.g. ivermectin (collies sensitive)
Milbemycin - e.g. moxidectin
How do MLs work? Why is this safe in animals?
Stimulate release of GABA
Hyperpolarisation and paralysis
GABA transmission confined to CNS and drug cannot cross BBB - safe to animal
How can MLs be administered?
Injection
Oral
Topical
Are MLs local acting or systemic?
Systemic - lipophilic so stored in fat, slow release
What is a disadvantage of MLs?
Long half life = residues in meat and milk
What are the 2 types of insect growth regulators? Give an example of each
Chitin inhibitors - cyromazine
Juvenile hormone analogues (keep immature) - methoprene
Isoxazolines are the newest class of drug. Are they local or systemic? are they absorbed fast or slow?
Systemic
Rapid absorption
How do isoxazolines work?
Act on GABA/glutamate receptors
What are the advantages of isoxazolines?
Fast acting
Lasts 1 month
Give an example of 2 isoxazolines?
Afoxolaner
Fluralaner
What are 3 other ectoparsitides that aren’t in the broad spectrum categories?
Imidacloprid
Fipronil
Amitraz
How does imidacloprid work?
Binds to ACh receptors
Causes paralysis and death
In what animals is imidacloprid used? What is it effective against?
Companion animals
Flea adulticide - NOT ticks
How does fibronil work? What is an advantage of fipronil? What animals find fipronil toxic?
Block GABA transmitter
Highly lipophilic - long residual activity
Bees, fish
What is amitraz used for? Which species can it not be used in?
Ticks - cattle dogs
Not horses and cats as contraindications
