Ectoparasiticides

Question 1

Damage caused by ectoparasites

Answer 1

• Disturbing animals→ stress
• Blood-sucking → anaemia • Wounds, tissue injuries → serious infections, myiasis
• Vectors and intermediate hosts of viral, bacterial and parasitic diseases

Question 2

Role as vectors and intermediate hosts

Answer 2

• Fleas → eg. Dipylidium caninum
• Ticks (Ixodes, Dermacentor, Rhipicephalus) → eg. babesiosis, anaplasmosis, ehrlichiosis, Lyme disease
• Mosquitos → eg. dirofilariasis
• Phlebotomine sand flies → e.g. leishmaniasis

Question 3

Drug classification

Answer 3

• Adulticides → neurotoxins
• contact poisons
• systemic agents
• Insect growth regulators (IGRs)
• Repellents (DEET, pyrethroids)

Question 4

Selective toxicity

Answer 4

-Pharmacokinetics
• metabolism, blood-brain barrier (eg. P-glycoprotein ivermectin)
• slow absorption
- Pharmacodynamics
• eg. GluCl channels → depolarization or hyperpolarization
• nACh receptor sensitivity

Question 5

Dermal absorption…the most common route of administration

Answer 5

• Large, lipophilic molecules
• slow, but good absorption → low Cp
• prolonged absorption from the site of administration (subcutaneous tissue, sebaceous glands)
- Poor-moderate amount crosses the bloodbrain barrier

-Duration of action
• collars 4-8 months • spot on 4-12 weeks • spray, bathing days