Parasites

Question 1

Name 3 commonly used anthelmintic drugs and how each work

Answer 1

-benzimidazole - disrupt microtublin assembly
-tetrehydropyrimidines - bind to Ach receptors cause excitatory effect - spastic paralysis
-macrolytic lactones - inhibit GABA receptors and glutamate channels

Question 2

TRUE/FALSE = resistance to anthelmintics has reached critical levels in farm animals

Answer 2

true

Question 3

What is a common stage in a parasite life cycle to target ?

Answer 3

adult

Question 4

What other stages of the life cycle are targeted ? with examples

Answer 4

-blowfly strike - kill larvae ( adults harder to kill )
-fleas - multiple stages - give adulticides to animal and target younger on the environment

Question 5

Examples of parasites that pose a zoonotic , public health risk

Answer 5

-sarcoptic mange - zoonotic
-ticks transmit lyme disease

Question 6

What are two modes of action of ectoparasiticides ?

Answer 6

neurotoxins (adulticide)
insect growth regulators (juvenile, slow to act )

Question 7

How do neurotoxins work ?

Answer 7

act on CNS synapses,axons or NM junctions and cause spastic or flaccid paralysis

Question 8

Name some neurotoxic ectoparasitic drugs and what receptors they act on ?

Answer 8

-neonicatinoids - stimulate nictoninic Ach receptors
-organophosphates - inhibit cholinesterase
-Phenylpyrazoles - inhibit GABA
-Isoxazolines - inhibit GABA and CL channel
-macrocyclic lactones - stimulate CL channels
-Pyrethroids - stimulate Na channel

Question 9

What ectoparasites do neonicatinoids act on ?

Answer 9

fleas

Question 10

What ectoparasites do organophosphates act on ?

Answer 10

wide range - flea, ticks , flies , keds, lice

Question 11

What ectoparasites do phenylpyrazoles act against ?

Answer 11

fleas and ticks

Question 12

what ectoparasites do isoxazolines act against ?

Answer 12

fleas and ticks

Question 13

TRUE/FALSE = isoxazolines increase the seizure threshold

Answer 13

false - they decrease it

Question 14

What ectoparasites do macrocyclic lactones act against ?

Answer 14

-ecto and endo parasites

Question 15

TRUE/FALSE macrocyclic lactones can be neurotoxic to animals with MDR1 gene mutation - collies

Answer 15

true

Question 16

What ectoparasites do pyrethroids act against ?

Answer 16

fleas,flies ,keds ,ticks ,lice and some mites
and repelllant

Question 17

TRUE/FALSE pyrethroids are toxic to cats and aquatic life

Answer 17

true

Question 18

Name and briefly explain an example of a neonicatinoid

Answer 18

imidacloprid
- fleas and chewing lice dogs and fleas rabbits
-topical - will wash off

Question 19

Name and briefly explain an example of a organophosphates

Answer 19

diazinon
-sheep dip
-sheep scrab , blow fly , larvae , lice , ticks , keds

Question 20

Name and briefly explain an example of a phenylpyrazole

Answer 20

fipronil
-fleas , tick and chewing lice
-topical - washes off
-toxic rabbits

Question 21

Name and briefly explain an example of a isoxazoline

Answer 21

fluralaner
-demodex , sarcoptes
-red mite

Question 22

Name and briefly explain an example of a macrocyclic lactones

Answer 22

ivermectin
-toxic to chelonians
-used large , birds , exotics
-avoid for dogs/cats

Question 23

Name some examples of insect growth regulators (IGRs)

Answer 23

-S methoprene
-cyromazine

Question 24

What 3 ways do IGRs work ?

Answer 24

-juvenile hormone analogues
-chitin synthesis inhibitors
-triazine derivatives

Question 25

Other forms of ectoparasitic drugs

Answer 25

-repellents
-lime sulphur dip