Ectoparasites

• Ectoparasites


  • Arthropods
  • Have jointed legs
  • Have chitinous exoskeleton made of up segments (head, thorax, abdomen)
  • Have a true body cavity, circulatory, digestive, respiratory, excretory, nervous and reproductive system
  • Have separate sexes that reproduce using eggs
  • Only some are parasitic
• Ectoparasite

  If the parasite lives on the surface of its host it is classified as an ectoparasite
• Ectoparasites

  • Insects- have 3 pairs of legs, 3 distinct segments and a single pair of antennae (fleas, lice, flies, mosquitos)
  • Arachnids (adults)- have 4 pairs of legs, a body with 2 segments (cephalothorax and abdomen) and no antennae (ticks, mites, spiders, scorpions)
• Fleas


  • Order: Siphonaptera
  • Most common dog and cat flea: Ctenocephalides canis and felis
• Flea life cycle


  Adult> egg> larvae> pupae> adult
• Adult fleas are bloodsuckers and lay their eggs in the environment. Larvae once hatched, eat "Flea Dirt" which is dried feces of the adult and other debris. The pupae that is spun from the Larvae are very resilient and hard to destroy. They hatch depending on the humidity and temperature. Vibrations such as those from a vacuum also can stimulate hatching.
• Flea related problems


  • Fleas are vectors for: Bubonic plague and intermediate hosts for other parasites such as tapeworms
  • Fleas can cause anemia or loss of overall blood supply if there are many on one animal feeding at once
  • Fleas can be the cause of Extreme Allergic Reaction called FAD or Flea Allergy Dermatitis
  • Fleas also are thought to transmit Mycoplasma hemofelis, a red blood parasite
• Approach to flea treatment

  1. Treat the House

  2. Treat the Environment

  3. Treat the Animals
• Types of flea treatments

  • Insecticides, most of which work by targeting the nervous system or agents that inhibit growth or the development of adult fleas
• Lice

  Two types: Mallophaga- the biting or chewing variety, Anoplura- the sucking variety
• Trichodectes Canis


  The dog louse
• Lice life cycle


  1. Eggs (nits) glued to hair

  2. Hatch into nymph stage

  3. Metamorphose into adults

  4. Anoplura species use claws to hang onto host, Mallophaga hang on via mandibles
• Lice related problems


  • Sucking louse can produce anemia in severe infestations (pediculosis)
  • Capable of transmitting diseases such as Tapeworm on rare occasions
• Lice treatment


  Insecticides, Ivermectin 1%, Monthly topicals such as fipronil, imidicloprid, or selemectin for flea control
• Mosquitos


  Family: Culicidae
• Mosquito life cycle


  Complex but can complete in less that 2 weeks if conditions are ideal
• Mosquito related problems


  • Vectors for many other diseases including: heartworm, West Nile Virus, WEE/VEE/EEE, Malaria, Fowl Pox, and many more
• Mosquito control


  1. Remove all standing water or breeding habitat

  2. Use "mosquito fish" in water such as water troughs or ponds

  3. Prevent bites with insecticides such as Skin So Soft or Spot on's like Canine Advantix

  4. Do not use products that contain DEET
• Cuterebra


  A particularly ugly larvae that infests rabbits, squirrels, mice, cats, and occasionally dogs
• Cuterebra larvae


  • Penetrate the hosts skin and live in a subcutaneous pseudocyst with a fistula (breathing hole)
  • Must surgically be removed
  • Live mainly in the soil of rodent burrows
• Hypoderma


  A hypoderma fly ("Ox Warble") Infestation found in Southern US. that affects cattle
• Hypoderma larvae


  • Lay eggs on the cattles legs and then the larvae migrate through the skin to the back producing breathing holes
• Gastrophilus


  Bot flies found in equine, commonly called a stomach bot
• Gastrophilus life cycle


  1. Adults look like honeybees

  2. Eggs are laid on the legs where the horse may lick or near the muzzle

  3. Larvae migrate through the tongue to the stomach
• Arachnids


  • Ticks
  • Mites
  • Spiders
  • Scorpions
• Ixodidae


  Hard shell ticks
• Rhipicephalus sanguineus


  The brown dog tick found in all of North America, can set up shop indoors
• Dermacentor variabilis


  The American Dog Tick found in all of North America, only inhabits shrubs and grasses
• Dermacentor andersoni


  The Western US "Wood Tick" carries Rocky Mountain Spotted Fever and can also cause paralysis
• Ixodes Pacificus


  The Western Black Legged Tick or the "Deer Tick" carries the spirochete Borrelia Burgdorfori, which is the causative agent of "Lyme Disease"
• Argasidae


  Soft-shell ticks
• Otobious Megnini


  The Spinous Ear Tick found in the South western US, larval and nymph stages are found in the external ear canals
• Argasidae: Soft-shell tick

  life cycle

  1. Incubation period for eggs is approximately 30 days

  2. Eggs hatch in to seed ticks (6 legged)

  3. In 24 hours the seed tick attach to a host

  4. They feed for 3-6 days

  5. Seed ticks drop off the host and molt in 1-2 weeks

  6. They emerge from this as an 8 legged nymph

  7. Nymph attach to a host and feed for 4-9 days

  8. Nymphs drop off and molt into adults in about 12 days

  9. After 30 days the adult is ready to attach to another host and begin a new cycle

  10. Many tick varieties require three hosts to reach maturity
• Problems associated with tick infestations

  • Anemia
  • Transmission of many diseases including bacterial, viral, protozoal, and rickettsial pathogens (Erhlichia, Babesia, Rocky Mountain spotted Fever, Lymes disease, Tick paralysis)
• Tick removal


  1. Remove all ticks as soon as they are encountered

  2. Use forceps or special tick removal instruments

  3. Do not apply heat or chemicals to entice the tick to come out

  4. Do not squish or pop ticks
• Tick prevention


  Use spot on and collars that promote repellent abilities or kill ticks on contact (Frontline Plus, K9 Advantix)
• Mites


  • Have 8 legs as adults and 6 legs as nymphs
  • Head, thorax, and abdomen are fused with no mandibles or antennae
  • Microscope needed for identification
• Demodex


  Follicular mite, highly host specific and do not transfer from pet to pet
• Demodex related problems


  • Localized alopecia or patchiness (local)
  • Diffuse alopecia, erythema, mild itching, and secondary bacterial infections (generalized)
  • Feet and face most severely affected
• Sarcoptes


  Sarcoptic mange, highly contagious to other dogs and can transfer to people but is self limiting, highly pruritic