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Y4 Farm - dermatology > Cattle ectoparasites > Flashcards

Cattle ectoparasites Flashcards

1
Q

Important ectoparasites of cattle

A
  • 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
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2
Q

Important ectoparasites of sheep

A
  • 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
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3
Q

Cattle lice

A
  • 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
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4
Q

Cattle lice species

A

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

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5
Q

Cattle lice infestation (pediculosis) - epidemiology, impact, diagnosis

A

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)

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6
Q

Cattle lice treatment

A
  1. Pour-on synthetic pyrethroid preparation such as deltamethrin (sucking and biting lice)
  2. Pour-on group 3-ML anthelmintics (ivermectin, doramectin and eprinomectin) (sucking and biting lice)
  3. 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.

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7
Q

Flies in cattle

A
  • 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
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8
Q

Pinkeye (Infectious bovine keratoconjunctivitis [IBK]): agent, vector, disease, signs

A

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

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9
Q

Stages of IBK

A

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

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10
Q

Neovascularisation of the eye

A
  • whole eye goes pink, then yellowy brown
  • can end up with eyes rupturing
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11
Q

IBK tx

A
  • Antibiotics
    – Routes; IM, SC, topical, subconjunctival (subconjunctival AB not more effective than IM)
  • NSAIDs
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12
Q

IBK prevention

A
  • Fly control with topical synthetic pyrethroid
    – e.g. Permethrin
  • Biological control
    – Friendly flies/parasitic wasps
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13
Q

Onchocerca: what is it? vector? tx?

A
  • 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
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14
Q

Warble fly (cattle grubs)

A
  • 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
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15
Q

Impact of warble fly

A
  • 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
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16
Q

Management of warble fly

A

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

17
Q

Cattle mites - mange

A

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

18
Q

Cattle surface mites

A
  • 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.
19
Q

Implications of chorioptic mange

A
  • scrotal mange
  • fertility implications for cattle and sheep
  • increases temperature of testicles
  • check for on BSE
20
Q

Cattle ticks

A

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.

21
Q

Tick life cycle

A
  • 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
22
Q

Consequences of tick infestations

A
  • 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
23
Q

Ticks as vectors

A
  • 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
24
Q

Babesiosis and theileriosis

A
  • 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
25
Q

Theileria

A
  • T. annulata – tropical theileriosis
  • T. parva – East Coast Fever
  • Cattle diseases in Africa (and for tropical theileriosis also parts of tropical Asia)
  • Found in local bovids in which cause little disease, but cause severe disease in domestic cattle and especially European breeds.
    – Lymphadenopathy
    – Fever
    – Haemorrhages
    – Anorexia, collapse, pulmonary oedema, dyspnoea and death.
26
Q

Babesia

A
  • Babesia bovis –Europe spread by Rhipicephalus sp.
  • Babesia divergens in Northern Europe spread by Ixodes ricinus, (causes disease in cattle, sometimes zoonotic).
  • Cause pyrexia, severe haemolytic anaemia haemoglobinuria and potentially death of infected animals, commonly known as red water fever in cattle
  • Calves tend to be fairly resistant to disease and acquire immunity. Disease occurs if naïve animals are brought into an endemic area
27
Q

Tick diagnosis

A
  • Previous history
  • Examination of skin often confirms presence of ticks
  • Examination of skin scrapping and/or sticky tape impressions may reveal ticks or eggs
  • Treatment may include blood transfusion/imidocarb (NB very long withdrawal)
28
Q

Tick control

A

Host Control
- Some pour on pyrethroids or MLs?
– none in the UK licensed for ticks in cattle
– Need to be reapplied at regular intervals
– Impact on GI worms

Environment Control
- Active and start to feed in early spring
- start and duration difficult to predict precisely
- Avoid tick prone pastures if possible?
- Attempts to decrease tick population = pasture improvement
– drainage and scrub clearance
- Not able to use acaricide

Control challenging as ticks spend most of their life cycle off the host

29
Q

Cattle photosensitisation

A

Occurs when the presence of a chemical makes skin become sensitive to sunlight (particularly UV wavelengths). This leads to skin damage and loss, particularly in unpigmented areas

30
Q

Cattle photosensitisation aetiology

A

1.Direct photosensitisation occurs when the chemical comes from a defect in the animals metabolism of its red blood cells, or, more commonly, from plants such as St. John’s wort.
2. Secondary photosensitisation occurs in animals with liver damage. This damage interferes with the complete breakdown of chlorophyll, resulting in the accumulation of a photosensitive chemical.
3. Local photosensitivity can also result as a reaction to the sap of some plants.

NB – terminology varies slightly across species. Direct photosensitisation is sometimes referred to as primary or type 1 photosensitisation
Secondary (or hepatogenous) photosensitisation is sometimes referred to as type 3 photosensitisation.

31
Q

Cattle photosensitisation CS & diagnosis

A
  • Non-pigmented skin affected
  • Hair loss, reddening, peeling
  • Ulceration of skin
  • Crusting, bleeding

Diagnosis made on CS

32
Q

Cattle photosensitisation tx

A
  • Removal to cool shaded housing
  • Fly control
  • Supportive therapy
33
Q

Cattle photosensitisation prevention

A
  • Do not breed from animals with photosensitisation due to a genetic defect
  • Identify and remove possible plant sources of photosensitising chemicals

Y4 Farm - dermatology (3 decks)

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