Ectoparasites

Ectoparasites

1. Fleas

   • Ctenocephalides felis (cat flea)
     • Infects: cat, dog, rabbits, ferrets, small rodents and man
   • Ctenocephalides canis (dog flea)
     • Infects: dogs (mainly in Ireland)
   • Clinical signs
     • Non-hypersensitive animals
       • moderate
         • anaemia in severe cases
       • prescence of fleas and flea dirt
     • Sensitised animal
       • pruritus (itchiness)
       • self-trauma
       • crusting
       • truncated hairs
       • alopecia
       • cats: miliary dermatitis
         • multifocal distribution of skin lesions, with no identifiable pattern
   • Life Cycle
     • Adult Flea - lays up to 50 eggs/day
       • Eggs fall off animal, contaminating home/surroundings
         • eggs hatch within 2-5 days to form larvae
         • larvae feed off flea dirt and debris in environment
           • larvae cocoon
           • flea emerges 1-4 weeks later
             • an remain dormant for up to 6 months before re-infesting animal
       • only need two fleas per animal to complete life cycle
   • Control
     • Kill adult flea on host
       • Frontline
     • Kill development stages in environment
       • Cleaning/vacuuming
       • Insectidice/insect growth regulator sprays

2. Lice

   • Life cycle
     • 1st nymph, 2nd nymph, 3rd nymph, adult, mature adult, egg.
   • Significance
     • heavy louse infection
       • pruritis
       • hair loss
       • skin thickening
       • scurfiness
     • severe cases
       • weight loss
       • anaemia
   • Treatment
     • Transmission - direct contact only
     • Frontline

3. Ticks

   • 3 host life cycle
     • only feed for a few days each year
       • Year 1: Six-legged larva
       • Year 2: Eight-legged nymph
       • Year 3: Eight-legged adult
         • eggs
   • Carry diseases
     • Lyme Disease
       • caused by spirochaete bacteria from the genus borrelia
         • in man and dog
   • Treatment
     • tick hook removal
     • Frontline
   • Can be associated with secondary bacterial infections
     • predispose to fly strike
     • anaemia
     • inappropriate removal can lead to granulomas

4. Mange Mites

   • mange - skin disease of domestic animals caused by a numberof different mites
   • life cycle
     • all on host or within its skin
     • many of the host stages can remain infective off the host for several days
     • direct contact not always needed for spread
   • 1. Otodectes - Ear Mites
     • dog and cat
   • 2. Cheyletiella
     • surface living
     • causes pruritus, hair loss and scaling
     • C. yasguri - Dogs; C. parasitovorax - rabbit, guinea pig
   • 4. Sarcoptic mange
     • Zoonotic
     • Clinical Signs
       • small nodules and pustules
       • scaling
       • pruritus
       • alopecia
       • constant scratching
     • Treatment
       • Selamectin
         • Stronghold
       • Aludex (Amitraz)
       • Advocate
   • 3. Demodectic Mange
     • lives in hair follicles and sebaceous glands
     • in Britain, only in dogs (D. canis)
       • dogs infected by their dams after birth
     • part of the normal canine flora
       • clinical disease occurs when cell mediated immune responses fail