DERMATOLOGY - Ectoparasite control - LAs Flashcards
What are the different ectoparasiticides used in large animals? 5
- Avermectins / MLs
- permethrins
- OPs
- IGRs
- synthetic pyrethroids (SPs)
How do avermectins/ MLs work as ectoparasiticides?
- bind to glutamate-gated chloride channel receptors
- flaccid paralysis of the pharynx
- internal and external parasites affected
- easy administrated (cf. OP dips)
How do permethrins work as ectoparasiticides?
- affect insect Na channels
- insect paralysis
- highly toxic in water courses
How do organophosphates (OPs) work as ectoparasiticides?
- AChE-R blocking
- highly toxic to all species (humans! - high PPE essential)
- Diazinon is the only UK approved active ingredient
- sheep dips
How do IGRs work as ectoparasiticides?
chitin synthesis interference
Name 2 IGRs and how they work
- CYROMAZINE - interferes with chitin synthesis
- DICYCLANIL - molting interference
What causes post-dipping lameness?
If using OP sheep dip, if left in bath overnight, E.rhusopathie can grow in this environment then infect next sheep through small abrasions
What is the only antifungal licensed for farm animals?
Enilconazole (expensive! vaccines may be more cost-effective)
Are OPs licensed in cattle?
No but they are licensed in sheep
Which ectoparasiticides are licensed in pigs?
only avermectins/ MLs
What ectoparasiticides are licensed in poultry?
nothing
What are your 3 main consideration when treating skin disease in farm animals?
- food safety
- environmental safety
- impact on other control programmes
Outline synthetic pyrethroids (SPs) as an ectoparasiticide
- block Na channels (nerves) –> paralysis
- there are a number of analogs
- licensed in sheep and cattle
- no other species in NOAH
What is the standard withdrawal time?
- Eggs/milk - 7d
- Meat - 28 d
- Double for organic farms
- Longer if vet deems necessary
How is sheep scab treated? 2
MLs and OPs
