Ectoparasites

• What are ectoparasites?


  Parasites that live outside or on host

  - incl. insects (flies, fleas and lice) and arachnids (ticks, mites)
• Cat Flea


  Ctenocephalides felis- can act as an intermediate host for tape wormDipylidium caninum

  
• Dog flea


  Ctenocephalides canis

  
• Hedgehog flea


  Archaeopsylla erinacei

  
• What is the lifecycle of a flea

  1.Eggfor 2-14 days2.larvaefor approx. 1 week3.pupaefor 2 days to 6 months4.adultfeeds and mates then the female will lay her eggs- lifecycle can take 2-3 to 6-7 months
• canine sucking louse


  -linognathus setosus-> may cause: pruritis, alopecia, anemia-SMALL HEAD

  
• canine biting/chewing louse:


  -trichodectes canis-> may cause pruritis, alopecia

  -BIG HEAD
• Feline biting/chewing louse


  -Felicola subrostratus-> may cause pruritis, alopecia
• What is the lifecycle of a louse

  - takes approx. 14-21 days

  1. egg

  2. First moult 2 days after hatching (nymph 1)

  3. Second moult 5 days after hatching (nymph 2)

  4. Third mould 10 days after hatching (nymph 3)

  5. Adult -> start reproducing before dying
• Treatment of biting and sucking lice

  Biting lice- imidacloprid- Fipronil- SelamectinSucking lice- no licensed products- use same as biting lice
• Flies


  - larvae ofgreen/blue bottles cause flystrike (myiasis) in rabbits and sheep- may cause signif. damage, extreme cases may need euthanasia
• How can damage from flies be prevented

  - good management

  - use of products such as Rearguard (cyromazine), an insect growth regulator
• Myiasis


  = caused by common green bottle flies

  - eggs are laid on host and feed on hosts surrounding tissues when hatched

  - secrete harmful enzymes to aid digestion -> eating host alive

  - carry pathogens from rotting flesh
• What factors play a role in the development of myiasis

  warmth, moisture, urine and excrement build up, lack of ventilation, lack of grooming and hygiene, injury (open wound)
• How may myiasis be prevented


  Regularly check fur/wool, keep environment clean, regularly groom & shaving, preventative measures when flies are seen
• What types of mites are there

  -surface (live on skin debris e.g. cheyletiella)

  -burrowing (tunnel into skin surface e.g. sarcoptes OR some borrow deep into hair follicle e.g. demodex
• What is the lifecycle of a mite

  - 2-3 weeks

  - entirely on or within host's skin

  - egg -> larvae -> nymph -> adult
• Otodectes (canis/felis)


  - ear mite- surface mite-clinical signs: scratching, head shaking, brown waxy discharge- treatment with spot-on and ear drops

  
• Cheyletiella


  - surface mite- infects dogs, cats, rabbits and guinea pigs-clinical signs:pruritis, alopecia, dry scaling of the skin
• Sarcoptes Scabei


  - burrowing mite-zoonotic- tends to be host specific- entire lifecycle takes 2-3 weeks-Clinical signs:lesions, intensely pruritic, alopecia, thickening of the skin-Sarcoptes scabei var. canis= canine scabies-Notoedres Cati= feline scabies

  
• Demodectic mange


  - demodex canis & demodex cati-clinical signs:pustular inflamed skin, thickening of the skin with hair loss- difficult to cure- Found in hair follicles

  
• Harvest Mite


  - surface mite-clinical signs:skin lesions and pruritis whilst feeding for 5-7 days
• What are general mite treatments

  - advocate

  - aludex

  - stronghold

  - ivermectin
• Types of ticks


  1.Ixodesricinus

  2.Ixodeshexagonus

  3.Ixodescanisuga
• What is the lifecycle of a ixodes ricinus

  - lifecycle takesthree years on three hosts

  - feeds for only a few days each year, as a larvae in the first year, a nymph in second and adult in third

  -egg -> larvae -> nymph -> adult
• Clinical signs of a tick

  - rarely cause disease by themselves

  - can pass disease pathogens to their hosts -> act as a vector

  - can carry: lymes disease, looping ill, babesiosis, ehrlichiosis