Hippoboscidae

• Also known as louse flies

• The two genera of veterinary importance are Hippobosca and Melophagus

Hippobosca spp.

• Also known as forest flies

• Only parasitises horses and cattle

• Only found in the Old World

• Large numbers found around the perineum and inner thighs

Recognition

• 1cm long

• Reddish brown

• Yellow spots on thorax and abdomen

• Clear wings

• Reduced wings with veins crowded towards anterior margins
  • Not a strong flier

• Forward pointing proboscis which can be retracted into head when not feeding
  • Both males and females suck blood

Life cycle

• Adults are on the wing between May and October

• Adults mate on the host

• Single larvae laid in soil or damp humus

• Adult flies emerge the following spring

Pathogenesis

• Irritation and annoyance from bites

• Mechanical vectors of non-pathogenic Trypanosoma theileri in cattle

Control

• Topical insecticide application
  • Repellents with residual action

Melophagus spp.

• Also known as sheep ked

• Found worldwide

• Bites sheep and goats
  • A separate species is found on deer

Recognition

• 4-6mm long

• Hairy

• Forward pointing proboscis

• Short head

• Reddish brown colouring

• Dorso-ventrally flattened

• 'Tick-like' in appearance

• Wingless

• Strong legs and claws

Life cycle

• Whole life cycle spent on the host
  • Adults may survive for 1 week off the host

• Single larvae laid on fleece which pupate

• Adult keds emerge a few weeks to a few months after pupating depending on environmental temperature

Pathogenesis

• Most numerous in autumn and winter

• Located in the superficial layers of the fleece
  • This aids transmission

• Long wooled breeds are most susceptible to infection

• Cause anaemia

• Wool damage
  • Irritation and self-inflicted damage
  • Staining by ked faeces

• Intermediate host for non-pathogenic Trypanosoma melophagium in sheep

Control

• Sheep dipping and spraying

• Shearing to decrease numbers