Ectoparasites Flashcards
Lice in cattle
Bovicola bovis - most common, chewing, usually on the head
Linognathus vituli - sucking, around the head
Haematopinus eurysternus - sucking, around the horns
Treatment of lice in cattle
Pour-on synthetic pyrethroid - deltamethrin (kills everything)
Pour-on group 3 ML - ivermectin, doramectin, eprinomectin (kills everything)
Injectable group 3 ML - ivermectin, doramectin, eprinomectin (removes sucking and >98% biting)
Infectious Bovine Keratoconjuntivitis - agent, vectory, signs
Moraxella bovis bacterium
Face fly
Corneal ulcers, oedema, lacrimation, opacity, epiphora
4 stages of Infectious Bovine Keratoconjunctivitis
1 - tearing, lacrimation, photophobia, small central corneal ulcer
2 - ulcer spreads across cornea, cloudy cornea, neovascularisation, pink cornea
3 - ulcer spreads, inner eye fills with fibrin and WBCs, eye looks yellow/brown
4 - ulcer covers entire cornea, iris adhesions
Treatment of Infectious Bovine Keratoconjunctivits
Antibiotics - IM, SC, topical, subconjunctival
NSAIDS
Prevention - fly control with synthetic pyrethroids (eg. cypermethrin), biological control (friendly flies/parasitic wasps)
Mites
Surface feeders - Chorioptes spp., Psoroptes spp.
Burrowing - Sarcoptes spp., Demodex spp.
Ticks in livestock
Ixodes ricinus
Haemaphysalis punctate
Diagnosis of tick infestations
History
Examination of skin
Examination of skin scarping/sticky tape impressions (ticks or eggs)
Control of ticks
Host control
- no licenced pour-on SP or MLs
Environmental
- avoid tick prone pasture
- improve pasture to decrease tick populations
- cannot use acaricide
Aetiology of photosensitisation in cattle
Direct photosensitisation occurs when a chemical comes from a defect in the animals metabolism of its RBCs, or plant such as St Johns wort
Secondary photosensitisation occurs in animals with liver damage which interferes with the complete breakdown of chlorophyll, leading to accumulation of a photosensitive chemical
Local photosensitivity can result as a reaction to the sap of some plants
Clinical signs and diagnosis of Photosensitisation in cattle
Non-pigmented skin is affected
Hair loss, reddening, peeling
Ulceration of skin
Crusting, bleeding
Diagnosis based on clinical signs
Treatment and prevention of photosensitisation in cattle
Move to cool, shaded housing
Fly control
Supportive treatment
Treatment of liver failure (if present)
Do not breed from affected animals
Identify and remove possible plant sources
Lice infestation (pediculosis) in sheep
Biting - Damalina (Bovicola) spp.
Sucking - Haematopinus spp., Linognathus spp.
Clinical signs of pediculosis in sheep
Asymptomatic
Pruritis
Excoriation
Fleeces damage/loss
Severe infestations can cause anaemia
Can look similar to scab
Diagnosis of pediculosis in sheep
Visual inspection
Direct microscopy of hair samples
Treatment of lice in sheep
Pour-on synthetic pyrethroid - deltamethrin, cypermethrin (kills biting lice)
Organophosphate dips (kills everything)
Treat all animals in direct contact
Diseases spread by ticks
Louping ill
Tickborne fever
Tick pyaemia (sheep only)
Control of ticks
Host control
- avoid buying naive animals
- synthetic pyrethroids - deltamethrin, cypermethrin
- OP dips - care with application, immediate kill
Environmental control
- expose lambs while they have passive protection
- avoid tick prone pastures
- decrease tick population
Sheep scab
Psopties ovis
How long is sheep scab viable off the host and how long is the prepatent period?
17d off host
PP 14d
Diagnosis of sheep scab
Skin scrape - from edge of lesions, funnel shaped suckers
Blood coproantigen ELISA - early diagnosis and deciding on which animals to treat
Treatment of sheep scab
OP dip - diazinon
Group 3 ML injection - moxidectin, doramectin, ivermectin
How many days of protection do the group 3 MLs have on scab treatment?
Moxidectin - 28d
Doramectin - 14d
Ivermectin - 0d
What are the challenges with controlling sheep scab?
Safety of chemical control measures
Resistance of mites to MLs and increased exposure to GI parasites
Cannot use 2% formulations of moxidectin in animals that have had footvax vaccine as it will kill them
Sub-clincial scab infestations
Biosecurity
Farmer motivation - social stigma leads to under-reporting
Control of sheep scab
Quarantine - min 2wks
OP dips
Serology - blood test with high sensitivity and specificity gives ability to detect scab withing 2wks of infestation
