Parasitology: Ectoparasiticides Flashcards
What kind of parasite prevention should pets be on?
year round prevention
What is mode of action?
How the drug works
What is spectrum of action
organism affected (broad spectrum vs. narrow spectrum)
Efficacy
how effective the drug is against an organism
how is efficacy usually measured
measured in % reduction for parasites that can be counted
What is residual activity
length of time a drug maintains efficacy after administration
Which agency regulates drugs given internally?
the FDA (approves and regulates them)
Which agency regulates drugs that are given topically, but are absorbed?
FDA
Which agency regulates drugs that are given topically, and are meant strictly for external activity only?
The EPA
Which agency also looks for environmental impact?
The EPA
What does it mean when the FDA or EPA say a product will treat for parasites/pests?
you get the assurance that there will be at least a 90% removal of existing burden from parasites
Does FDA use the word control?
no, just the EPA
When the EPA says “control,” what are they referring to?
that at least 90% of organisms exposed after treatment will be eliminated
When the word prevention is used, is it referring to infection or disease?
disease, not infection
What does “repellant” refer to? What is the specified time period?
disrupting normal behavior during host-seeking. No specified time period
What are the two primary TYPES of pesticides
- those that kill or repel organisms
- those that interfere with normal growth and development
What does “knock-down” mean?
it refers to the rapid action of a pesticide
What does speed of kill refer to?
how long a pesticide takes to have its effect
What kind of repellants are there?
- vapor repellents
- contact repellents
what is the difference between vapor and contact repellents?
vapor repellents do not require the organism to touch the host. Contact repellents require the parasite to touch the compound
how does a surface-diffusion spot-on/pour-on pesticide work?
it spreads out over the animal surface
how does a transcutaneous spot-on/pour-on pesticide work?
the pesticide is absorbed and distributed through the blood (ex: Revolution)
What is a synergist?
an agent that acts with or enhances the activity of another
are synergists pesticides?
no
How do synergists work?
they are added to pesticides to slow down the metabolism of the active pesticides
what are two main examples of synergists?
- piperonyl butoxide
- N-octyl bicycloheptene
What do Insect Development Inhibitor compounds affect? What stage does this affect?
they affect chitin synthesis. Larval stage
what are two examples of IDIs?
- luferon
- cyromazine
What do Insect Growth Regulators affect?
They are Juvenile hormone analogs, and thus affect growth and maturation, preventing the ability of the insect larvae to progress forward in development
What are some examples of IGRs?
- Methoprene
- pyriproxyfen
T/F. Compounds that affect growth and development are often combined with adulticides in topical small animal preparations
true
T/F. Oral feed-through pesticides pass through the animal harmlessly and with low toxicity to target the larvae that are eliminated in fecal matter.
True
Insect Growth Inhibitors: Examples, formulation, site of action
ex: methoprene and pyriproxyfen
formulation: topical
site of action: Juvenile hormone
Insect Development Inhibitors: Examples, formulation, site of action
Ex: lefenuron, cyromazine
Formulation: topical, oral
Site of Action: chitin formation
Isoxazoline: examples, formulation, site of action
Ex: afoxolaner, fluralaner
Formulation: oral, topical
Site of Action: synapses (Gaba, glu)
macrocyclic lactones: examples, formulation, site of action
Ex: selamectin, eprinomectin
Formulation: topical, oral, injectable
Site of Action: synapses (gaga, glu)
phenylpyrazole: examples, formulation, site of action
Ex: fipronil
Formulation: topical
Site of Action: synapses (gaba, glu)
spinosyns: examples, formulation, site of action
Ex: spinosad
Formulation: topical, oral
Site of Action: synapses (ach)
organophosphates and carbamates: examples, formulation, site of action
Ex: dichlorvos, tetrachlorvinphos, carbaryl
Formulation: topical
Site of Action: synapses (ach)
botanicals: examples, formulation, site of action
Ex: pyrethrins
Formulation: topical
Site of Action: ion channels
pyrethroids: examples, formulation, site of action
Ex: ends in -thrin (permethrin, cyfluthrin)
Formulation: topical
Site of Action: ion channels
oxidiazenes: examples, formulation, site of action
Ex: indoxacarb
Formulation: topical
Site of Action: ion channels
formamidines: examples, formulation, site of action
Ex: amitraz
Formulation: topical
Site of Action: monoamine oxidase inhibitor
neonicotinoids: examples, formulation, site of action
Ex: imidicloprid, nitenpyram, dinotefuran
Formulation: topical
Site of Action: synapses (acetylcholine
Which pesticide groups are used in large animals?
- insect growth regulators
- insect growth inhibitors
- macrocyclic lactones
- organophosphates and carbamates
- botanicals
- pyrethroids
T/F: Of the listed pesticide groups in this class, small animals can only use a small number.
false, they can use all of them
Differentiate between older pesticides and newer pesticides,
Older, clunky pesticides:
- less expensive, less specific to arthropods, which leads to a higher risk of toxicity
Newer, cooler pesticides may be:
- more expensive
- more specific to arthropods, leading to lower risk of toxicity
T/F: natural products are regulated.
False; there is no assurance of safety or efficacy, so it is hard to recommend these products
T/F: Pyrethrins are commonly used without synergists.
false, they are commonly used with synergists
Pyrehthrins are what _____ products, and are _____ metabolized by_____
- plant
- quickly
- light
What is the mode of action of pyrethrins?
- disrupt ion transport in sodium membranes
- cause convulsions and paralysis of organism
( quick knockdown, repellent activity)
What is the spectrum of action for pyrethrins?
generally insecticidal or acaricidal
What are the available methods of application for pyrethrins?
- topical (but it can be licked off)
- sprays
- dusts
- shampoos
- environmental
T/F: Pyrethrins are generally considered safe because it is rapidly metabolized.
True
What kind of problems can occur if overingestion of pyrethrins occurs?
toxicity issues, such as salivation, diarrhea, vomiting, trembling
What are Pyrethroids?
synthetic, pyrethrin-like compounds that act like roid-raging pyrethrins
Which compound is more persistent and potent, pyrethrins or pyrethroids?
py…re…THROIDSSSSSSSS
what are the general rules and exceptions of pyrethroid identification?
- if it ends in “-thrin,” it’s a pyrethroid
exceptions: fenvalerate and etofenprox
Is etofenprox a true pyrethroid?
no, its just pyrethroid-like
what is the most commonly used pyrethroid?
permethrin
what are the modes of action for pyrethroids?
- disrupt ion transport in sodium membranes
- cause convulsions and paralysis of organism
( quick knockdown, repellent activity)
what are the spectrums of activity for pyrethroids?
generally insecticidal or acaricidal
why is the risk of toxocity greater in pyrethroids than pyrethrins?
pyrethroids are more potent and last longer.
What are some dangers about discussing pyrethrins and pyrethroids?
- people mix them up easily, and misgroup them
- people call the pyrethroid the permethrin group
What are the modes of administration for pyrethroids?
topical (dusts, sprays, shampoos, spot-ons, pour-ons)
Why are Organophosphates and carbamates used less widely now?
safety issues, such as toxicity
What is the mode of action for organophosphates and carbamates?
- they act as acetylcholine inhibitors
- persistent depolarization of membranes => death (sadly, it does this to humans too)
What are two carbamate products that still around for small animals?
- Carbaryl and Propoxur
Where would you be able to find organophosphates today?
- some large animal pesticides
- possibly some OTC flea collars (but most were removed due to safety concerns)
What are some signs of toxicity due to organophosphate/carbamate?
- salivation
- diarrhea
- collapse
What is/are the spectrum(s) of action for formamidines?
primarily ticks and mites (Acaricidal)
What is the mode of action for formamidines?
monoamine oxidase inhibitor
What are the toxicity concerns of formamidines? What are the clinical signs of toxicity?
- DO NOT USE IN HORSES
- do not combine with other monoamine oxidase inhibitors (like Anipryl in dogs)
- signs: lethargy, hypotension, vomiting
What is the method of administration for formamidines?
topical, not absorbed for activity
What is the persistence of formamidines?
days
T/F: Ivermectin is derived from a natural fungal product that can be found in the soil.
True
What is another name for the macrocyclic lactones?
- macrolides
- endectocides
Why are macrocyclic lactones also called endectocides?
macrocyclic lactones are effective against both internal and external parasites
what are the two subgroups of macrocyclic lactones?
avermectins and milbemycins
What are some examples of avermectins?
- ivermectin
- doramectin
- eprinomectin
- selamectin
What are some examples of milbemycins?
- milbemycin
- moxidectin
What is the mode of action for macrolides?
- bind to glutamate gated chloride channels, leading to hyperpolarization of nerves and muscles
- can also affect parasite reproduction
Do macrocyclic lactones have any residual effects against parasites?
yes, it depends on the product’s formulation and how lipophilic the drug is
Macrocyclic lactone spectrum of action?
- insectidcidal and acaricidal, depending on the drug, the formulation, and the parasite
macrocyclic lactone modes of administration
- oral
-spot-ons - injections
feed additives
What are some examples of neonicotinoids?
- imidacloprid, nitenpyram, dinotefuran
What is the mode of action for neonicotinoids?
binds to acetylcholine receptors in insects
What is the spectrum of action for neonicotinoids?
insects mostly on animals and plants
What is the method of administration for neonicotinoids?
topical mostly
What is the biggest concern regard the use of neonicotinoids?
it affects honeybees
How many Spinosyns are in use and what are they?
- only one
- spinosad
What is the spectrum of activity for spinosyns?
insects
What is the mode of action for spinosyns?
similar to neonicotinoids in that they bind to acetylcholine receptors, but they bind to a different location
What are spinosyns used for in small animals?
flea treatments
Are spinosyns large or small molecules?
large, kind of look like microcyclic lactones
What are the modes of administration for spinosyns?
oral and topical
How many phenylpyrazoles are in use and what are they?
only one
- fipronil
- its in Frontline
What is the spectrum of activity for phenylpyrazoles?
insecticide and acaricide
What is the mode of action for phenylpyrazoles?
they bind to GABA reeptors
What are the toxicity concerns for phenylpyrazoles?
- doesn’t seem to bind to mammalian receptors, but DO NOT use them in rabbits or fish
What are the modes of administration for phenylpyrazoles?
topical, no absorption. It’s lipophilic, released from hair follicles and sebaceous glands
What are some examples of Isoxazolines?
- afoxolaner
- fluralaner
- sarolaner
What is the spectrum of activity for Isoxazolines?
insecticidal and acaricidal
What is the mode of action for Isoxazolines?
they bind to GABA receptors, and are specific to arthropods
What are the modes of administration for Isoxazoline?
oral, and now topical
What does “eat to kill” mean?
it means that the parasite must bite the host to be affected by the parasiticide. Drugs like Nexgard use this method.
What are some concerns regarding “eat to kill?”
some are worried that the initial bite may still cause issues in the host
T/F: Isoxazolines can be used in large and small animals.
False. It is currently only used in small animals
What is lime sulfur used for in small animals?
its used to treat mite infestations
Is there a DEET for animals?
nope, only plants
What are some examples of inert inorganic pesticides?
- boric acid
- diatomaceous eart
How are inert inorganic pesticides used?
they’re used in the environment to desiccate organisms (primarily larval stages)
Where does DDT fit in?
chlorinated hydrocarbons (aka organochlorines aka DDT) is no longer available in the US. It is still used internationally.
What are some examples of DDT?
lindane
dieldrin
aldrin
methoxychlor
