Kingdom: Phylum: Class: Order
Animalia Arthropoda Insecta Phthiraptera
Wings
None
Divisions
Head, thorax, abdomen
Body shape
Dorso-ventrally flattened
Number of segments in antennae
3-5 segments
Type of parasite
Obligate, permanent parasite
Specificity
Host and site specific
What is the claw size of a louse related to?
Fibre diameter
Can lice survive off a host?
No, whole lifecycle is found on a host
Pairs of legs
3
Life cycle
Egg stuck to hair
No metamorphosis
3 nymphal stages
Length of life cycle
2-3 weeks
Two taxonomic groups lice are divided into
Anoplura
Mallophaga
A = Anoplura
B = Mallophaga
Anoplura: feeding strategy
Sucking lice Feed on blood or tissue fluids
Anoplura: # of segments on antennae
5
Anoplura: shape of head
Longer than broad and pointed
Anoplura: hosts
Mammals only
Anoplura: three families
Haematopinidae Linognathidae Pediculidae
Genera of Haematopinidae family
Haematopinus
Genera of Linognathidae family
Linognathus Solenopotes
Genera of Pediculidae family
Pediculus Phthirus
Anoplura: habitat
Coarse hairs (mane, tail) Eggs readily visible
Anoplura: colour/size
Large, black or blue
Anoplura: transmission
Contact
Anoplura: treatment
Topical or oral insecticide
Mallophaga: feeding strategy
Biting lice Feed on epidermis, feathers
Mallophaga: shape of head
Head broad, rounded
Mallophaga: antennae
Thin, 4-5 segments
Mallophaga: hosts
Mammals and birds
Mallophaga: habitat
Fine body hairs Eggs concealed
Mallophaga: colour/size
Small, yellow
Mallophaga: transmission
Contact
Mallophaga: treatment
Topical only
Mallophaga: Genera with Mammal hosts
Damalinia Heterodoxus Trichodectes Felicola
Mallophaga: Genera with Bird hosts
Menacanthus Lipeurus Gonioides Goinocotes
Lice of the sheep
Body louse: Damalinia ovis Face louse: Linognathus ovillus Foot louse: Linognathus pedalis
A = Damalinia ovis
B = Linognathus ovillus
C = Linognathus pedalis
Damalinia ovis: features
Small yellow louse 30% properties affected Medium rainfall areas
Damalinia ovis: effect on host
Feeds on stratum corneum Hypersensitivity Irritation, rubbing “Pulled wool” Reduced wool production
Damalinia ovis: diagnosis
Find lice on sheep Part wool and look Minimum detection level 1000 lice per sheep Lice colonial and photophobic
How long do D. ovis eggs take to hatch?
10 days
How long is the lifecycle of D. ovis?
35 days
How long can D. ovis live off the host?
1 week
What is D. ovis affected by?
Temperature Moisture Sunlight
Effect of temperature on D. ovis
Optimum temperature 37 deg At low temperatures, eggs do not develop At high temperatures (above 39) few eggs are laid Lower numbers in summer
Effect of moisture on D. ovis
If humidity > 90%, eggs do not hatch Heavy rain can kill eggs
Effect of sunlight on D. ovis
Exposure to sunlight kills lice Shearing removes 30-50% of lice as lice are exposed to UV radiation
When should D. ovis be treated chemically?
After shearing
What treatments are available?
Dips: Organophosphates or synthetic pyrethroids Pour-ons: Synthetic pyrethroids
Linognathus pedalis
Large blue louse Feeds on blood Found on feet, scrotum and belly Can develop at lower temperatures than D. ovis Attaches eggs to coarser hairs than D. ovis
What’s special about L. pedalis?
Can survive on pasture for 18 days Can be transmitted through pasture
Linognathus ovillus
Uncommon Found on face
Lice of the goat
Damalinia caprae Linognathus africanus & stenopsis
Lice of the horse
Body louse: Damalinia equi Sucking louse: Haematopinus asini
A = Damalinia equi
B = Haematopinus asini
How is Damalinia equi transmitted?
Contact
How is Haematopinus asini transmitted?
Riding and grooming equipment
Damalinia equi
Small yellow louse Found on sides of neck and flanks
Haematopinus asini
Large dark louse Occurs on coarser diameter hairs Species can survive away from host for several days
A = Damalinia bovis
B = Haematopinus eurysternus
C = Solenopotes capillatus
D = Linognathus vituli
Lice of cattle
Body louse: Damalinia bovis Sucking lice: Short nosed cattle louse: Haematopinus eurysternus Tubercle bearing louse: Solenopotes capillatus Long nosed cattle louse: Linognathus vituli
Cattle sucking lice
Maximum numbers in winter Found on head, neck, back, tail Causes rubbing Larger numbers in sick animals
Lice of the pig
Sucking louse: Haematopinus suis
Haematopinus suis
Haematopinus suis
Haematopinus suis: Lifecycle
Eggs hatch 12-14 days Lice mature 12 days
Haematopinus suis: size
Very large, mistaken for a tick
Haematopinus suis: pathogenesis
May spread pig pox and swine fever Causes red welts on skin –> production loss
Lice of the dog
Trichodectes canis Heterodoxus spiniger Linognathus setosus
A = Trichodectes canis
B = Linognathus setosus
C = Heterodoxus spiniger
Pathogenesis of Trichodectes canis
Can act as an intermediate host for the “flea tapeworm” D. caninum
Lice of the cat
Felicola subrostratus
Felicola subrostratus
Felicola subrostratus
Biting louse Pointed head Seen on aged or sick cats
Significance of heavy lice infestation in cats
May indicate underlying disease as cats are generally good groomers in health
Lice of poultry
Many genera, all biting Menacanthus Stramineus most common
A = Menacanthus Stramineus
B = Lipeuris caponis
Pathogenesis of poultry lice
Irritation Feather loss Poor growth Reduced egg production
Treatment of poultry lice
Dust baths, aerosols, vaporisers
Lice of humans
Head/body louse: Pediculus humanus, Pediculus capitis
Pubic louse: Phthirus publis
Pathogenesis of lice of humans
Vectors of typhus