Treatment and prevention of equine parasitic disease Flashcards
(18 cards)
Current anthelmintic resistance Cyathstomes to ivermectin, moxidectin, fenbendazole and pyrantel
Ivermectin: emerging
Moxidectin: emerging
Fenbendazole: widespread
Pyrantel: resistant/not too bad in UK
Current anthelmintic resistance large strongyles to ivermectin, moxidectin, fenbendazole and pyrantel
Ivermectin: okay
Moxidectin: okay
Fenbendazole: okay
Pyrantel: okay
Current anthelmintic resistance ascarids to ivermectin, moxidectin, fenbendazole and pyrantel
Ivermectin: widespread resistance
Moxidectin: widespread resistance
Fenbendazole: anecdotal
Pyrantel: few published cases (USA)
Treatment of clinical cases
▪Treat animals with clinical signs of disease
What would you use moxidectin for?
- larval cyathostominosis
What would you use pyrantel for?
- colic due to high Parascaris burden
What would you use praziquantel or double the standard dose of pyrantel for?
- recurrent colic and high ELISA for Anaplocephala
Prevention of larval cyathastominosis
▪No control strategies is a bad idea -> clinical disease given our stock densities
▪Maintenance of parasite burdens low enough to mitigate clinical signs is the goal
– strategic use of anthelmintics
– pasture management
Pasture management
▪Appropriate stocking
▪Faecal collection
– Minimum of twice weekly
– Larvae do not stay in faeces or recognise electric fencing
▪Dung heaps separate from grazing area ▪Pasture rotation
– Best to rest pastures in in hot dry condition as larvae overwinter in mild winters
– Hot dry condition more likely to kill off the parasites
▪Grazing with ruminants
Creation of refugia
▪Treat those with high parasite burdens (if possible)
▪Minimize pasture contamination
▪Create a large percentage of parasites not exposed to anthelmintics
▪10-20% of horses produce 80% of the eggs
Which horses to treat – recommendations
▪Must be a yard wide approach
▪Treat if faecal WEC > 250epg (Based on testing every 8-12 weeks
throughout the grazing season) with ivermectin or pyrantel
▪Perform a faecal egg count reduction test after 14 days to assess efficacy of treatment
▪Treat new arrivals at yard and hold away from turn out for a minimum of 3 days (or ideally until FWEC reduction) is assessed
▪For young horses WEC are required more frequently
Low risk factors for parasitic infection
- Repeated negative WEC or Tapeworm Ab levels
- Cohort negative WEC or tapeworm Ab levels
- 5-15 years of age
- Faecal collection > twice per week
- Stable population/ low stocking density
- No youngstock
- No history of colic or parasitic disease
- Effective quarantine
Moderate risk factors for parasitic infection
- Low/ moderate WEC or Tapeworm Ab levels
- Cohort low/ moderate WEC or tapeworm Ab levels
- > 15 years of age
- Sporadic faecal collection
- Medium stocking density
- Occasional movement
High risk factors for parasitic infection
- High WEC/ tapeworm Ab levels
- Cohort high WEC/ tapeworm Ab levels
- < 5 years of age
- No faecal collection
- Transient population/ high stocking density
- Co grazing with youngstock
- History of colic / parasitic disease
- No quarantine
- Anthelmintic resistance as documented
by FWECRT
Tx of low risk horses
▪Low risk
– No Autumn treatment
– But do require regular FEC & tapeworm ELISA in spring & autumn
Tx of moderate/high risk horses
- 1 dose of moxidectin (or ivermectin) in Autumn
– trying to remove any early L3 larvae before they become hypobiotic - debate re moxidectin vs ivermectin
– moxidectin will kill all stages that aren’t hypo biotic but if used for prevention, will have nothing for tx or no protection for the tx of clinical cases
– ivermectin just kills the majority of adults and can lead to the activation of hypo biotic larvae, so can sometimes made the dz process worse
When should you do an ELISA test for tapeworm? When to treat it? What with?
▪Tapeworm ELISA in spring and Autumn and treat if high Ab titre with pyrantel/praziquantel
What risk category are most horses in the UK?
- moderate or high risk
