Ectoparasiticides Flashcards
Name the major classes of ectoparasiticides (8)
- organochlorines
- organophosphates
- synthetic pyrethroids
- macrocyclic lactones
- neonicotinoids
- phenylpyrazole
- Isoxazolines
- Insect growth regulators
What is the Mode of Action of OPs?
Ach released from insect nerve ending, normally inactivated by acetylocholinesterase- OPs bind to AchE, Ach builds up = paralysis
What ectoparasites do OPs target?
blowfly, lice, ticks, mites, keds
What is the Mode of Action of SPs?
excites cell membranes by maintaining depolarisation, Na+ channels stay open = paralysis
Which ectoparasites do SPs target?
flies, lice, ticks
What contraindication is there to SPs?
permethrin toxicity in cats
What is the Mode of Action of MLs?
Stimulate GABA release from nerve endings, enhancing binding to its receptor in post-synaptic motor neurone membrane + increasing flow of Cl- (hyperpolarisation) = paralysis
Which ectoparasites are targeted by MLs?
mites, lice, bots, warbles
What contraindications are there against the use of MLs as an ectoparasiticide?
collies are sensitive to ivermectin, long meat/ milk withdrawal period
What is the Mode of Action of Neonicotinoids?
Binds to nicotinic Ach receptors in insect central nervous system = paralysis
How do Phenylpyrazoles work as ectoparasiticides?
Blocks GABA transmitter = paralysis
What is the Mode of Action of Isoxazolines?
GABA + glutamate receptor antagonist (acts on Cl- channel in neurone synapses) = paralysis
How do IGRs work?
chitin inhibitor, prevents egg hatch + moulting
Which ectoparasites are targeted by Neonicotinoids?
fleas, T.canis (biting lice)
Which ectoparasites does phenylpyrazole target?
fleas, ticks
