Principles of ectoparasite controls

Question 1

Give an example where you may intervene at multiple stages of a parasite lifecycle?

Answer 1

fleas:
- adulticide to animal
- spray environment to affect juvenile stages

Question 2

How can contact with the parasite be avoided?

Answer 2

barriers
Most useful when only part of lifecycle is on host

Question 3

How can conditions be made unsuitable to ectoparasites?

Answer 3

Change host environment e.g., minimise pasture worm burden/ tail docking => reduce myiasis of sheep
Change off-host environment e.g., management of dung to avoid attracting flies

Question 4

What is the function of neurotoxins?

Answer 4

attack the nervous system of the parasite to kill it

Question 5

What is the function of insect growth regulators?

Answer 5

arrest parasite development

Question 6

What are the different drug actions for parasite control?

Answer 6

neurotoxins
insect growth regulators
repellants
dessicants
mechanical agents

Question 7

What drug-related factors need to be considered when choosing a drug for ectoparasite control?

Answer 7

Spectrum of activity (what parasite at which life stage)
Speed of onset required
Duration of action/frequency of application (compliance, animals that get wet)
Contraindications and drug interactions
Safety (patient, owner and humans, environment, non-target species)
Development of resistance
Cost and licensing (many are expensive and POM-V)

Question 8

What host factors need to be considered when choosing a drug for ectoparasite control?

Answer 8

species
age restrictions
suitable mode of application
Meat/milk withdrawal periods