Ectoparasites

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Ectoparasites

Place parasitic arthropods of veterinary importance into their classes based on morphology

Arthropod

Phylum = arthropoda

Invertebrates

Jointed limbs

6-8 legs

Waterproof exoskeleton

alpha chitin

Support + protection

Tanned /sclerotised

Hairs (Setae), bristles, spines, scales

Divided into plates = sclerites

Muscles attachment inside

Segmented body

2-3

Vascular system

Body cavity (Haemocoele) w blood

Nervous system

Ganglia = brain

Sensory organs

CO2

Temp

Vision

Eyes

Flies , compound

Palps???

Respiration

Gas exhange via openings in cuticle

Spiracles = insects

Stigmata = ticks + mites

Cover to prevent breathing - kill

Covered in hairs

Prevent entrance

Gut

Simple tube

Fore gut - food broken down

Mid gut - food stored /digestion

Hind gut - water absorption

Malpighan tubules - filter waste from haemolymph into gut

Feeding mouthparts

Classification

Insects

3 parts to body

Head

Thorax

Abdomen

3 legs from thorax

6 total

Wings possible

Two antennae

Specialised mouth parts

Arachnids

8 legs in adults

Fused body regions

Acari

2 parts to body

Cephalothorax

Abdomen

4 legs in adult

3 in larvae

No wings

No antennae

Specialised mouthparts

Separate sexes

Grow by moulting

Juvenile hormones

Gain a general understanding of seasonality ecology, behaviour and life cycles - all for informed control

Trilobites = ancient arthropods Mud dwelling

Oval body

Exoskeleton

Segmented jointed limbs

Could moult

Evolution

Insects

Flies

Free living / saprophagous/ temporary ectoparasites

Adaptions to breed in faeces

Adaptions to lay eggs skin

Lice

Permanent host specific

Blood / skin scales

Fleas

Wingless

Adapted to living in nests

Flat ventrally

Movement between hairs

Acarines

Mites

Free living

Usually permanent on skin

Ticks

Obligatory blood suckers

Temporary

Flat but fat when fed

Arthropod life cycles

Reproduction

Flies

Females must mate to obtain protein to mature eggs

Why flies pester cattle + mosquitoes/ticks suck blood

Mites + ticks

Female tick (on host) secretes pheromones to attract males

Male inserts mouthparts into female genital pore + deposits sperm packets

Spermatophore = sperm packet

Holometabolous

Complete metamorphosis

Flies

Egg-> Larvae-> Puparie (grub) -> flies

Temp dependent

Hemimetabolous

Incomplete

Lice + ticks

Immature stages look similar to adult

Define adverse effects on the host - tissue damage, allergies +/transmission of animal/human disease

Problems

Decline in milk

Weight gain

Tissue invasion

Blood loss

Toxic + allergic responses

Inflammation

Itching = pruritus

Skin damage

Welfare

Heavy infections

Self wounding

Secondary infections

Zoonoses

FAD

Mouthparts

Mandibles + maxilla = cutting + slashing

Labrum = upper lip

Hypopharynx = tongue - like

Labium /labellum = lower lip

Ticks

Salivary

Anticoagulants

Vasodilators

Cement?

Toothed hypostome

Curved teeth

Horse flies (haematopota)

Labellum slashes about to get blood

Painful to host

Mange = mite dermatitis

Parasites feed on skin scales, lymph fluids

Burrowing

Demodex

Non burrowing

Sheep scabies

Psoroptes ovis

Pediculosis = louse infestation

Understand economic + welfare aspect and recognise the generic need for surveillance +control of ectoparasites

Vectors of pathogens

Tsetse fleas

£4.5 billion /year losses in Africa

Blood sucking

Farmer can't rear animals in areas where these flies are endemic

Transmit another parasite (trypanosomes)

Unless tolerant breed

Tick born diseases

Common sheep tick - lyme disease

Meadow tick - transmits protozoa parasite

Common in Europe

Mechanical transmission

Hydrotaea irritans

Soak up secretions for egg batch

Spongy mouth parts

Mastitis cause

Modern problem

Intensification = abundance of hosts

Transport = imported livestock carry new parasites

Artificial selection - inc susceptibility

Controlled warm environments

Pets = vectors

Set aside??

Predicted inc in parasite abundance

Global warming

Emerging arboviruses

West nile virus

African horse virus etc

Surveillance

Endemic

Invasive vectors

Management + control