Cattle ectoparasites Flashcards
Important ectoparasites of cattle
- Lice – 4 species of louse – (1 biting, 3 sucking)*
- Mites – chorioptes mainly on tail head, self-limiting, also occasional rare cases of sarcoptic or psoroptic mange which are more severe
- Ticks – Vector for TBF (tick borne fever) and Babesia
- Flies – vector for Moraxella bovis and summer mastitis pathogens
- Warble Fly – Notifiable in Scotland (no UK outbreaks since 1990)
- Worms – Onchocerca – not a big issue clinically
Important ectoparasites of sheep
- Psoroptes ovis (sheep scab mite) – Severe and contagious**
- Myiasis (blowfly strike) – massive welfare concern*
- Lice – Less severe than sheep scab but associated with debility and weight loss
- Ticks – vector for Louping ill, S.aureus, TBF
- Head Flies – important for horned sheep
- Keds – uncommon and not a big issue
- Nasal Bots – uncommon, unpleasant when they do occur
Cattle lice
- Live on skin surface and can be seen easily by naked eyes
- Dark grey/brown in colour and ~ size of a flattened pin-head
- life cycle: direct & simple – eggs -[2w]-> nymphs -[2w]-> adults (live 4 weeks)
– permanent resident on host
Cattle lice species
Haematopinus eurysternus
- sucking louse
- around the horns
Linognathus vituli
- sucking louse
- around the head area
Damalinia (Bovicola) bovis
- most common
- chewing louse
- usually on the head
- may travel down the neck and body
Sucking - pointy heads
Biting/chewing - rounder heads
Cattle lice infestation (pediculosis) - epidemiology, impact, diagnosis
Epidemiology
- VERY COMMON
- Usually winter
– Coat thickness
- Don’t survive off the host
- More common in housed animals as closer together - transfer is usually by direct contact
Impact
- Decrease BCS/DLWG
- Damaged skins/fleeces
- Usually poor doers
- Low lice burdens may not cause any problems
- Higher burdens can cause itching, rubbing and licking, and possibly anaemia with sucking lice
- Clinical pediculosis may also be an indicator of another debilitating disease/malnutrition
Diagnosis
- Visual inspection (much bigger than mites)
Cattle lice treatment
- Pour-on synthetic pyrethroid preparation such as deltamethrin (sucking and biting lice)
- Pour-on group 3-ML anthelmintics (ivermectin, doramectin and eprinomectin) (sucking and biting lice)
- Injectable group 3-ML anthelmintics (ivermectin, doramectin and eprinomectin) will remove all sucking lice and >98% of biting lice
All cattle in direct contact must be treated. Treat at start of winter housing period if cattle are at risk
Most treatments aren’t effective against eggs so may need repeat treatments after 2 weeks to kill nymphs.
5% aqueous tea tree oil used in horses and may be an alternative to chemical ectoparasiticides.
Flies in cattle
- Flies are vectors for disease and irritation may cause reduced DLWG or milk yield
- Myiasis (blow fly strike) is rare in cattle compared to sheep
Pinkeye (Infectious bovine keratoconjunctivitis [IBK]): agent, vector, disease, signs
Agent: the bacteriumMoraxella bovis
Vector: Face fly (feeds on watery tears around the eye and spreads bacteria, travels to many animals in a day, so potential for rapid spread in herd, but likely that not all animals will develop signs)
Disease: 4 stages
Signs: corneal ulcers, oedema, lacrimation, opacity, epiphora
Can get asymptomatic carriers
Stages of IBK
Stage I: tearing, lacrimation, photophobia, small central corneal ulcer
Stage II: ulcer spreads across the cornea, cloudy cornea, neovascularisation, pink cornea
Stage III: ulcer spreads, inner eye fills with fibrin and WBC, eye looks yellow/brown
Stage IV: ulcer covers entire cornea, iris adhesions
Neovascularisation of the eye
- whole eye goes pink, then yellowy brown
- can end up with eyes rupturing
IBK tx
- Antibiotics
– Routes; IM, SC, topical, subconjunctival (subconjunctival AB not more effective than IM) - NSAIDs
IBK prevention
- Fly control with topical synthetic pyrethroid
– e.g. Permethrin - Biological control
– Friendly flies/parasitic wasps
Onchocerca: what is it? vector? tx?
- Thin, white worms found in the eye of cattle
- Vectors: blackfly or cullicoides
- Ocular infection:
– ranging from acute oedematous necrosis to chronic granulomatous changes
– results in marked fibrosis and mineralization. - Treatment:
– Systemic ivermectin
– Anti-inflammatories - Not in the UK
Warble fly (cattle grubs)
- Hypoderma bovis and Hypoderma lineatum
- Have very similar life cycles
- Adult warble flies are hairy and about the size of a small bee with yellow/orange abdomens
- They lay eggs on the hair of cattle in summer, larvae hatch and migrate into the skin then travel to the oesophagus and spinal cord where they lay dormant over winter
- In spring they travel back under the skin, mature for around 30 days then drop off and pupate in the soil
- The warble fly emerges around 36days later
Impact of warble fly
- Gadding behaviour: Flies cause harassment to cattle, which become
– (1) restless leading to physical injuries
– (2) depressed, leading to decreased production and growth - Ectopic migration & Paralysis
- Damage caused by warbles
- Downgrade of the hide caused by perforations of skin by breathing larvae
- Reduced reproduction: caused by large number of warbles under skin in spring
Management of warble fly
Treatment:
- OPs - 98% effective in autumn and less efficient in spring
Control:
- In 1978 – Legislation was introduced to dress all obvious warble-infested cattle in spring
- First 5 years of eradication, the incidence reduced from 34% to 0.02%
- Since 1990 no living larvae have been found on British Cattle.
- Have been eradicated, but still notifiable in Scotland
- All imported cattle must be treated on arrival
Notifiable disease in Scotland
Cattle mites - mange
Surfaces feeders
- Chorioptic mange most common in cattle (Chorioptes bovis) – see on tail head and legs
– non jointed pedicles and cup shaped sucker
- Psoroptic mange (Psoroptes spp) is rarer in cattle in UK but causes intense itching
– jointed pedicles and trumpet shaped sucker
Burrowing mites
- Sarcoptic mange (Sarcoptes spp) also less common, but there is anecdotal evidence that it is increasing
– non jointed pedicles and rounder than chorioptes. Also has a central patch of triangular scales on its dorsal surface
- Demodex spp
Cattle surface mites
- Chorioptes most common (tail mange, leg mange, scrotal mange [may impact fertility])
- Characteristic locations
- Deep skin scrapes still required to get a good sample from the edge of a lesion
- Sharp scalpel – scrape until you get capillary oose
- Treatment is Permethrin (Synthetic pyrethroid) or pour on Macrocyclic lactones (injectable less effective)
- Following treatment also need to move animals from infected area.
Implications of chorioptic mange
- scrotal mange
- fertility implications for cattle and sheep
- increases temperature of testicles
- check for on BSE
Cattle ticks
Ixodes ricinus
- Scotland, Wales, north and south-west England and occasionally in Dorset and the south-east.
- Most common
Haemaphysalis punctate
- Coastal areas of Wales.
Tick life cycle
- adult female seeks a host, engorges with blood and mates before dropping off
- engorged female lays from 1k-10k eggs and then diets
- larva hatches from egg and seeks a host
- nymph seeks host
- engorged nymph shelters in grass and moults to adult
- only present on the host for a short period of time
- 3 hosts so disease spread can go to 3 hosts
Consequences of tick infestations
- Poor body condition
- Weight loss & reduced milk yields
- Hide/fleece damage – reduction in quality
- Intense irritation – associated behavioural issues
- Lesions may form around areas of bites – in some instances opportunistic bacterial infections may occur
-Prolonged infestation may result in small granuloma formation due to retention of mouth parts or salivary secretions - The main risk they pose is as a vector for disease, but bites can cause inflammation and hypersensitivity
Ticks as vectors
- In some species ticks may act as vectors for secondary pathogens, complicating your diagnosis and treatment of the disease. These are often also of zoonotic importance
- Viral: tick-borne encephalitis
- Bacterial: tick-borne fever (TBF), Lyme borreliosis, Q-fever, tick-borne relapsing fever
- Parasitic: Babesiosis
Babesiosis and theileriosis
- Are similar to the protozoans that cause malaria and sleeping sickness
- They parasitise the red blood cells of vertebrates, and can be transmitted transovarially as well as transstadially in ticks
- tend to cause little disease in endemic areas
