Parasiticides

Question 1

How does the dose of ivermectin for heartworm prevention differ from its use in other parasitic diseases and how does this impact use in the ivermectin-sensitive breeds?

Answer 1

The dose for heartworm is 6μg/kg po every month
The dose in other parasitic diseases in 0.2 mg/kg sc
The dose used in other parasitic disease may be toxic to sensitive dogs with ABCB1-1Δ gene defect

Question 2

What is the effectiveness of febantel in dogs and cats?

Answer 2

Both dogs and cats, hooks, rounds, and whips

Question 3

What is the effectiveness of fenbendazole in dogs and cats?

Answer 3

Roundworm, hookworm, whipworm, Taenia tapeworm

Extra label action against roundworm, hookworm

Question 4

What is the effectiveness of macrocyclic lactones (ivermectin family) in dogs and cats?

Answer 4

Dogs (extra-label) and cats: hookworm

In dogs, it has variable efficacy against rounds and whips

Question 5

What is the effectiveness of praziquantel in dogs and cats?

Answer 5

Tapeworms (Echinococcus granulosus)

Question 6

What is the effectiveness of pyrantel pamoate in dogs and cats?

Answer 6

Roundworms and hookworms in dogs

Cats: extra label against rounds and hooks

Question 7

What is the effectiveness of fenbendazole in horses?

Answer 7

Large and small strongyles, pinworm, ascarids (particularly effective)

Question 8

What is the effectiveness of macrocyclic lactones (ivermectin family) in horses?

Answer 8

Effective against everything except tapeworms

Effective against benzimidazole resistant cyathostome

Question 9

What is the effectiveness of piperazine in horses?

Answer 9

Ascarids, some activity against large and small stronglyes

Question 10

What is the effectiveness of pyrantel pamoate in horses?

Answer 10

Large and small strongyles, ascarids, pinworms
Also tapes (Anoplocephala perfoliata)

Question 11

What is the effectiveness of macrocyclic lactones (ivermectin family) in cattle?

Answer 11

Oesophagostomum, Ostertagia, Haemonchus

Question 12

What is the effectiveness of clorsulon in cattle?

Answer 12

Fasciola

Question 13

What is the effectiveness of albendazole in cattle?

Answer 13

Oesophagostomum, Ostertagia, Haemonchus, Fasciola

Question 14

What is the effectiveness of fenbendazole in cattle?

Answer 14

Oesophagostomum, Ostertagia, Haemonchus

Question 15

What is the effectiveness of morantel in cattle?

Answer 15

Oesophagostomum, Ostertagia, Haemonchus

Question 16

Why do benzimidazole anthelmintics like fenbendazole require three daily doses in dogs but only require one dose to be effective in ruminants and horses?

Answer 16

Dogs and cats do not produce the metabolite as well as horses and cattle, so it needs to be give multiple times to be effective

Question 17

Which of the following is the safer form of pyrantel and why: pyrantel pamoate or pyrantel tartrate?

Answer 17

Pyrantel pamoate because the pamoate salt is poorly absorbed from the GI tract

Question 18

How does natural pyrethrin differ from the synthetic pyrethroids in terms of duration and potency against ectoparasites that a susceptible to this group of agents?

Answer 18

Natural pyrethrin: quick knock down, but short duration
If you spray an insect with natural pyrethrin, it will be dying within seconds

Synthetic pyrethroids: 1st generation is identical to the natural pyrethrin
They have a much slower kill than the natural pyrethrin.
Apply to an animal and fleas are still running around a couple of hours later, but it still works

Question 19

Why is piperonyl butoxide combined with natural pyrethrin insecticides?

Answer 19

Piperonyl butoxide is a synergist inhibiting detoxification enzymes in the insect

Question 20

Permethrin is contraindicated in what species?

Answer 20

Cats and fish

Question 21

What protocol does the American Heartworm Society recommend as the best way to treat dogs to remove adult heartworms?

Answer 21

AHWS recommends a 3 dose regimen of melarsomine. One dose, wait 30 days, then 2 doses 24 hours apart

Question 22

Address why the “three dose protocol” (also called the “split protocol”) of melarsamine is now preferred over the original “two dose protocol”.

Answer 22

The two-dose protocol is only 90% effective and the 3 dose is 98% effective

Question 23

Why are doxycycline and prednisolone used as part of the HW protocol?

Answer 23

Doxycycline (given before treatment) reduces the severity and the incidence of pulmonary embolism after adulticide therapy and it affects Wolbachia. Prednisolone is used to control the signs of pulmonary embolism after treatment with melarsomine

Question 24

When is heartworm preventative begun prior to heartworm adulticide therapy and why?

Answer 24

ML is given 2 months before giving melarsomine to eliminate immature worms less than 60 days, allows worms older than 60 days to mature to an age that is susceptible to melarsomine, reduces or eliminates microfilariae levels, and stunts adult HW development

Question 25

What is the hypothesis proposed for how a few heartworm variants in the Mississippi Delta are resistant to the macrocyclic lactone preventatives?

Answer 25

There are genetic differences at four SNPs in resistance isolates. The p-glycoprotein pump in the organisms is involved. It normally pumps out the ML a little, but it still kills the larval form. In the resistant strains, they think something has mutated the gene for the pump so there are a lot more pumps or they have the same number of pumps, but they are more efficient

Question 26

What macrocyclic lactone product has shown effectiveness against the Mississippi Delta resistant strains of heartworms in a laboratory disease model?

Answer 26

Advantage multi (moxidectin) was 100% effective in both strains of worms

Question 27

Anthelmintic resistance is now documented for ivermectin in which of equine internal parasite(s)?

Answer 27

Parascaris

Question 28

Which of the anthelmintic(s) should not be used during early gestation in cattle, sheep, or goats due to embryo toxicity or teratogenicity?

Answer 28

Albendazole

Question 29

Which small animal topical product used for internal parasite control has been shown to interfere with fetal development in lab animals and should not be handled by women who are pregnant or may become pregnant?

Answer 29

Emodepside

Question 30

Which oral small animal anthelminthic is contraindicated in pregnant animals?

Answer 30

Pyrantel + Praziquantel + Febantel (Drontal plus)

Question 31

Carbaryl (Sevin®) belongs to what family of insecticides? What is its antidote if overdosed into toxicity?

Answer 31

Carbamates, but these are no longer available for animal use | Atropine is used to treat an overdose

Question 32

What is Afoxolaner (NexGard) effective against? Is is given topically or orally?

Answer 32

Fleas and ticks | Oral

Question 33

What is Amitraz effective against? Is is given topically or orally?

Answer 33

Ticks | Topical

Question 34

What is Carbaryl (Sevin) effective against? Is is given topically or orally?

Answer 34

Fleas and ticks | Topical

Question 35

What is Dinotefuran (Vectra) effective against? Is is given topically or orally?

Answer 35

Fleas | Topical

Question 36

What is Fipronil (Frontline) effective against? Is is given topically or orally?

Answer 36

Fleas and ticks | Topical

Question 37

What is Fluralaner (Bravecto) effective against? Is is given topically or orally?

Answer 37

Fleas and ticks | Oral in dogs, topical in cats

Question 38

What is Imidacloprid (Advantage) effective against? Is is given topically or orally?

Answer 38

Fleas | Topical

Question 39

What is Indoxacarb (Activyl) effective against? Is is given topically or orally?

Answer 39

Fleas | Topical

Question 40

What is Nitenpyram (Capstar) effective against? Is is given topically or orally?

Answer 40

Fleas | Oral

Question 41

What is Permethrin effective against? Is is given topically or orally?

Answer 41

Fleas and ticks, but more effective on ticks | Topical

Question 42

What is Sarolaner (Simparica) effective against? Is is given topically or orally?

Answer 42

Fleas and ticks | Oral

Question 43

What is Spinosad (Comfortis) effective against? Is is given topically or orally?

Answer 43

Fleas | Oral

Question 44

How does the combined use of spinosad with deworming doses of ivermectin cause toxicity?

Answer 44

It is a p-glycoprotein pump inhibitor and can cause toxicity when given with drugs that are a substrate for the pump

Question 45

How do lufenuron, methoprene, and pyriroxyfen differ from traditional insecticides in terms of how they affect the flea cycle?

Answer 45

Lufenuron: chitin synthesis inhibitor Methoprene, pyriproxyfen: juvenile hormone mimic Juvenile hormone must be absent for a pupa to molt into adult; breaks the life cycle of the insect Pyriproxyfen is more stable because methoprene degrades when exposed to UV light

Question 46

What side-effect is most commonly seen with amitraz dip and what can be used to reverse it?

Answer 46

Can cause sedation in some dogs | Reversible with alpha-2 antagonist

Question 47

What enzyme system is inhibited by amitraz thereby predisposing to adverse drug interactions?

Answer 47

MAO (monoamine oxidase) inhibitor

Question 48

What ectoparasites are the macrocyclic lactones (ivermectin family) effective against?

Answer 48

Sarcoptic mange Otodectes (ear mites; when given both systemically and topically) Demodectic mange (extra-label daily use)

Question 49

What is effective against demodectic mange?

Answer 49

Extra label use of macrocyclic lactones (ivermectin family) Amitraz topically Afoxolaner Fluralaner Sarolaner

Question 50

What is uinique above selamectin (Revolution) as a macrocyclic lactone?

Answer 50

Its effective against fleas

Question 51

Tetrachlorvinphos (Equitrol®), diflubenzuron (Equitrol II®). and cyromazine (Solitude IGR®) are all “feed-through” fly control products. What does the term “feed-through” imply in terms of what life stage the act upon to help control flies? How does the percentage of animals receiving these products on a farm affect their usefulness?

Answer 51

Added as a top dressing to the grain of the horse and enters into the manure and in the manure it prevents the life cycle of the fly from completing when they legs in the manure Ever horse in the stable needs to be on this. If it is just one and there are 10 others, you will not get fly control

Question 52

Fenbendazole (Panacur®) may be superior to ivermectin when controlling what helminth in foals?

Answer 52

Ascardis

Question 53

Moxidectin (Quest®) may be more effective than ivermectin when controlling what helminth in adult horses?

Answer 53

Small strongyles

Question 54

Name two agents approved to treat liver flukes in cattle.

Answer 54

Clorsulon and albendazole

Question 55

Albendazole should not be used in what subgroup of cattle and why?

Answer 55

Do not give to lactating dairy cattle | They are lipid soluble and enter the milk very well

Question 56

Which older anthelminthic when injected in cattle causes occasional cholinergic toxicity (salivation, head shaking, ataxia, muscle tremors)?

Answer 56

Levamisole

Question 57

Which agents are effective against tapeworms, including Dipylidium, in dogs and cats?

Answer 57

Praziquantel and episprantel

Question 58

What is the deficiency in activity of epsiprantel versus praziquantel?

Answer 58

Esiprantel is not approved for Echinococcus granulosus whereas praziquantel is extremely effective against it

Question 59

What tapeworm species is fenbendazole only effective against?

Answer 59

Taenia Tapeworm

Question 60

What categories of insecticides are used in ear tags for fly control in cattle?

Answer 60

Macrocyclic lactones (Doramectin, Eprinomectin, Ivermectin, Moxidectin) Synthetic pyrethroids Organophosphates

Question 61

Fenbendazole is effective against what GI protozoal infection?

Answer 61

Giardia

Question 62

How is febantel related to fenbendazole? How does it differ relative to effectiveness against whipworms?

Answer 62

It is a prodrug of fenbendazole, which is subsequently further metabolized to active metabolites It claims to have single-dose efficacy against whipworms

Question 63

What role does albendazole have relative to echinococcus human infections?

Answer 63

Can treat the infection in the tissue phase, when there are large tissue cysts

Question 64

Albendazole has been advocated in the past for use in dogs. What major toxicity limits its usefulness in this species?

Answer 64

Bone marrow suppression

Question 65

What are the deficiencies in the spectrum for Heartgard (only ivermectin) in dogs?

Answer 65

No nematodes

Question 66

What are the deficiencies in the spectrum for Heartgard (only ivermectin) in cats?

Answer 66

No roundworms

Question 67

What are the deficiencies in the spectrum for Heartgard Plus (ivermectin and pyrantel pamoate) in dogs?

Answer 67

Does not get whipworms

Question 68

What are the deficiencies in the spectrum for Revolution (selamectin) in dogs?

Answer 68

Limited activity against hooks and whips

Question 69

What are the deficiencies in the spectrum for Proheart 6 (moxidectin 6-month sustained-release injection) in dogs?

Answer 69

Not effective against roundworms