Control of ectoparasites

Question 1

List some direct and indirect effect of ectoparasites

Answer 1

Direct:
-Pruritis/ skin lesions
- Blood loss
-Myiasis
-Production loss
Indirect:
-Pathogen transmission
-Accidental injury

Question 2

What is the difference between arachnida and insecta?

Answer 2

Arachnid= 2x body segments, 8x legs
Insecta= 2x body segments, 6x legs

Question 3

What protozoa do female mosquitoes transmit?

Answer 3

Plasmodium

Question 4

Why might eradication programmes fail?

Answer 4

• Socio economic factors
• Insecticide resistance
• poor surveillance

Question 5

What is the definition of control in terms of parasites?

Answer 5

-Reduciton of parasite load or vector population - aim is to reduce transmission

Question 6

List some of the methods used to control ectoparasites

Answer 6

• Chemicals
• Physical barriers
• Biological controls
• Trapping
• Forecasting

Question 7

What mode of action do most drug targeted at ectoparasites use?

Answer 7

Neurotoxins

• They act on the CNS synapse, axons or neuromuscular junctions
• Can cause spastic or flaccid paralysis
• Toxicity risk to humans as many insects/ mammals have same NTs

Question 8

What are the concerns regarding stop ons?

Answer 8

• Human toxicity
• Environmental toxicity
• Ingestion of product by other animals
• Skin lesions at application site
• Bathing can compromise effectiveness

Question 9

What are the concerns regarding parasite collars?

Answer 9

• Should be removed when animal sis bathing. swimming to avoid depletion of drug
• • Can have contact irritation
• Animal shouldn’t bite/ chew on it

Question 10

Describe some contraindications faced with ectoparasite control

Answer 10

• Pyrethroids: some cats v sensitive. Neurotoxicity issues.
• Macrocylcic lactones espesh ivermectin: Toxic to collies/ herding dogs
• Fipronil: toxic to rabbits
• Spinosad: dogs with epilepsy
• Advocate: contraindicated with other macrocyclic lactones e.g. milbemax
• Amitraz: not used by humans with diabetes mellitus

Question 11

List some physical control methods of ectoparasite control

Answer 11

• Remove moist/ warm bedding for biting/ non biting flies
• Manage dung: prevent ovipositing flies
• Change host environment e.g. tail dock, fly masks on horses

Question 12

Describe the use of biological controls at controlling ectoparasites

Answer 12

Using predators, parasites, competitors or pathogens of ectoparasite you are trying to control

• Can be used against parasites that live or reproduce in environment
• e.g. parasitic wasps for house flies