Parasitology - Ectoparasiticides Flashcards
Parasiticide
Drug that kills parasites
Pesticide
Drug used for external parasites/arthropods
Insecticides
Kills insects
Acaricide
Kills ticks and mites
Pesticide regulation
FDA can authorize drugs for animals
who approves drugs absorbed through the skin?
FDA
Who approves drugs with external activity?
EPA
Environmental protection agency
How are pesticide efficacy measured?
Treat (or remove)
EPA & FDA require 90% removal of existing parasite burden
How is efficacy of control pesticides measured?
EPA requires that the pesticide eliminates at least 90% of organisms after exposed to treatment
How is efficacy of repellent measured?
EPA only
Distrusts normal behavior during host seeking
Time period not specific
Types of pesticides
Direct lethal or repellant action
Or
Interfere with normal growth or development
Knock-down
Agents with quick rapid action
Speed of kill
How long a pesticide takes to have its effect
Repellency
Vapor repellent (citronella): may or may not get on host
Contact repellent: arthropod has to touch the compound
Spot/pour on treatments
Applied over small area
Surface diffusion: spreads over animal surface
Transcutaneous: absorbed & distributed through blood
Synergistic actions of pesticides
Agent that acts with or enhanced activity of another
Common in pesticides
Synergism that slows down metabolism of active pesticides
Piperonyl butoxide
N-octyl bicycleheptene
Compounds affecting growth & development
Kill bc organism can’t complete normal growth - don’t effect adults
IDI
Insect development inhibitors
How does IDI work?
Synthesis of Chitin inhibitors
Examples of IDI
Lufenuron
Cyromazine
IGR
Insect growth regulators
Functions and examples of IGR
Juvenile hormone analogs
Methoprene
Pyriproxyfen
Modes of compound administration
Topical
Combined w adultcide in small animals
Oral feed - common in LA
Environmental use
Common use with compound pesticides
Effective in SA
Low toxicity
Commonly used for fleas (SA) and flies (LA)
Older fashioned pesticides
Less expensive
Less target specific
More common OTC
New fashioned pesticides
More expensive
Host specific (less toxicity)
Require vet sale
Common themes of pesticides on the market
Lots of pesticide drug groups, limited ways they work
More than 1 group can work at same sites but different molecular route
Different groups work differently, similar chemical compounds
Botanicals
Pyrethrins
Plant products
OTC prep
Short acting - metabolized by light
What type of pesticide is metabolized by light?
Pyrethrins, botanicals
Mode of Pyrethrin action
Increased permeability of neuronal membranes (for NA)
Hyper excitability and death
Repellent activity
Method of pyrethrin application
Topical - not absorbed, can be licked off
Sprays, dusts, shampoos, environmental
Safe = rapidly metabolized
Pyrethoid compounds
Synthetic, more persistent in environment, same mode, same effect same spectrum: insecticidal & acaricidal
How many generations of pyrethroids?
5
Which generation of pyrethroids are more potent?
3rd generation
Suffix for pyrethroids
“Thrin”
Which species can pyrethrins be lethal in?
Cats
Which pyrethroids derivative is used in small animal products?
Etofenprox
Which pesticide lasts longer?
Pyrethroids - more potent too
Which pesticide has greater toxic potential?
Pyrethroids - more potent
Organophosphate, carbamates use
Not commonly used due to safety issues
Function of organophosphate & carbamates
Inhibits acetylcholinesterase = persistent depolarization of membrane
Target species for organophosphate & carbamates
Insecticidal & acaricidal
Groups of newer pesticides
Macrocyclic lactose’s
Neonicotinoids
Spinosyns
Isoxazolines
Phenlprazole
Macrocyclic lactones
Endectocides
Activity against internal & external parasites
Derived from products made by soil fungus
Two subgroups of macrocyclic lactones
Milbemycins
Avermectins
Subgroups of avermectins
Ivermectin
Doramectin
Eprinomectin
Selamectin
Subgroups of milbemycins
Milbemycin
Moxidectin
Mode of action in macrocyclic lactones
Bind to glutamate gated chloride channels = hyper-polarization of nerves/muscles
Multiple effects of macrocyclic lactones on muscles
Paralysis of muscles
Affects parasite reproduction
Some have persistent activity, affected by formulation /route
Spectrum of action for macrocyclic lactones
Insecticidal, acaricidal - dependent on drug, form, parasite
Modes of administration
Oral, spot-on, pour-on, injection, feed additives
Topical - best for ectoparasites
Topical become absorbed & become systemic
Neonicotinoids drugs
Imidacloprid
Nitenpyram
Dinotefuran
Spectrum of action for Neonicotinoids
Insecticide - NOT acaricide
Most useful for fleas
Toxicity of Neonicotinoids
Low in vertebrates - different receptors
Big concern for honeybees & invertebrates
Spinosyns drugs
Spinosad
Spinetoram
Mechanism of action of Spinosyns
Activate acetylcholine receptor but bind to a different location than Neonicotinoids
Spectrum of action for Spinosyns
Insecticidal, some acaricidal
Small animals for fleas
Risk & administration of Spinosyns
Low toxicity
Topical & oral
Derived from soil bacterium
Phenylpyrazole drugs
Fipronil
spectrum of phenylpyrazoles
Insecticide & acaricide
Mode of action of phenylpyrazoles
Binds to GABA receptors, limited effect in mammals
Don’t use on rabbits & fish
Mode of administration of phenylpyrazoles
Topical
Lipophilic - dogs shouldn’t be washed 2 weeks prior for ideal absorption
(Can also kill honey bees)
Isoxazolines drugs
Afoxolaner
Fluralaner (bravecto)
Sarolaner (simparica)
Lotilaner
Spectrum of action for Isoxazolines
Insecticidal & acaricidal - highly effective
Mode of action of Isoxazolines
Binds to GABA & glutamate gated chloride (different receptor than macrocyclic lactones)
Specific to arthropods
Formulations & administration of Isoxazolines
Oral & topical
“Eat to kill products” only works if blood is ingested
Prevents disease from Babesia & Borrelia (transmit after attachment for 24 h)
Side effects of Isoxazolines
Only problem is if DOG has history of neurological problems - can amplify problems
Miscellaneous pesticides
Lime sulfur
Boric acid
DE
Natural pesticide products
No scientific studies to support efficacy
Neem essential oil
Electronic collars
Amber
