Applied EQ parasitology

What are the risk factors for colic w/ regards to parasitology?

• No association w/ anthelmintic type / programme

• Increased risk if not on a worming programme

• Decreased risk if on a regular worming programme

• Increased risk after anthelmintic administration

Recall what the main parasitic cause of colic is?

• Strongylus vulgaris

  • Causing thrombosis of the cr. mesenteric a. & a non strangulating infarction

• Rarely seen since modern anthelmintics

What is post worming colic?

• Recognised following anthelmintic treatment of horses known to have high worm burdens

• Inflammation of the GIT subsequent to death of large numbers of parasites

What are the clinical signs of cyathostominosis?

• Weight loss, hypoalbuminea

• D+

• Intussusceptions

  • Caecocaecal

  • Caecocolic

• Can be ass. w/ high mortality

What GI issues is anoplocephala perfoliata (tapeworm) associated with?

• Spasmodic colic

• Ileal impactions

• Caecal intussusceptions

must be operated on

What do large burdens of parascaris equorum result in?

• Weight loss / unthriftiness

• Sl obstruction & colic

What is this? What can it cause?

Oxyuris equi

• Can cause peri-rectal irritation (tail rubbing)

What are these? When are they found?

Bot flies (gastrophilus intestinalis)

• Often incidental finding when performing gastroscopy

• Eggs often seen on horses legs during summer months

• Of no clinical significance in most cases

What is the aim of parasite prevention in youngstock?

Minimise exposure of youngstock to most pathogenic parasites → preventing (high) level of infection → reducing incidence of dx

What is the lifecycles of parascaris spp, cyathostomins & anoplocephala perfoliata?

What are the parasite specific anthelmintitic drug options?

How are diagnostic tools used to control parasites in youngstock?

• detect and monitor infection

• determine if current control measures are working

• direct appropriate intervention (e.g drug tx) if required.

• Reduce unnecessary drug use of drugs but balance w/ need to control parasite in most vulnerable age group.

• Risk-based evaluation currently considered best practice, but more difficult to do for youngstock

List some ways that parasite transmission can be reduced in horses aside from drugs

• Good pasture hygiene

  • Poo picking

  • Graze other stock (e.g. sheep) on pasture grazed by horses

  • Don't use high risk pastures for most vulnerable horses (<3yo)

  • If pastures permanent consider switching age groups on different pastures/ year

  • Quarantine

What are the priority parasites of foals & weanlings in the first 12 months of life?

Describe strongyloides westeri

• Rarely causes dx (self-limiting)

• Current recommendations NOT to pre-emptively treat mares

• Can do FEC @ 2-5wks (but not necessary)

What is the current recommendation of treating Parascaris spp?

• Treat 2-3months & again @ 4-5months

• FEC from 2-3mo —> help understand shedding patterns

• Confirm drug working by doung FEC reduction test —> use pyrantel & fenbendazole as ivermectin & moxidectin have resistance

At what are are strongyles seen in weanlings?

Anoplocephala perfoliata & strongyles such as cyathostomins start to be seen between 12-24mo

• Reduce risk by grazing weanlings on low-risk pastures

What is used to treat strongyles?

Ivermectinl, moxidectin, pyrantel —> effectiveness determinged by FEC reduction test

How can you diagnose a strongyle infection?

• FEC —> detects patent infection & doesn't differentiate between large and small strongyles (best done on every animal in co grazing group)

• Large strongyle larval differentiation test —> limitations due to long PPP

What threshold is used for treatment in FEC?

200-500epg to treat high shedders

What are the diagnostic tests for cyathostomins?

• Small redworm ELISA (blood test)

  • Total worm burden test- detected all stages not just adult

  • Complex interpretation- vet only

What are the diagnostic tests for tapeworms (A. perfoliata?)

• FEC —> centrifugation flotation (60& Se)

• Diagnosteq tapeworm ELISA (68% Se) —> detects exposure vs current infection

• EquiSal (saliva) —> same antigen as ELISA

Saliva/serum ELISA +ve frpm 6-7mo

How is anoplocephala perfoliata treated?

Double dose of pyrantel or praziquantel

What is used to diagnose tapeworms in yearlings?

• Saliva/serum ELISA or specialist FEC in spring to reduce egg shedding so fewer infected oribatid mites.

• Saliva/serum ELISA or specialist FEC in autumn to reduce parasite burden.

Describe sustainable parasite control

• Assess risk

• Natural risk mitigation

• Treat horses

• Consider parameters for tx to maintain in refugia population

• Treat horses w/ appropriate de-wormer

How does poo picking reduce transmission of parasites?

• Reduces no. of infective L3 on pasture

• Leads to lower mean FEC for grazing herd

Describe FEC for tapeworms

Can confirm current infection but lack sens, so absence of eggs challening to interpret.

Describe blood & saliva ELISA testing for tapeworms

Detect abs that indicate exposure to tapeworm —> reliable if used >4months after prev. tapeworm tx