Parasites - Ticks

• What do large numbers of ticks lead to

  Anaemia and blood loss
• What two other things can ticks lead to 


  tick paralysis and secondary infections such as blowfly strike
• Where do you find hard ticks

  Temperate climates
• Where do you find soft ticks

  warmer climates
• How do you identify a hard tick 


  They have a scutum which is a hard dorsal covering

  Prominent mouth parts

  Festoons (Notches) may be present

  Coloured patches - often males

  convoluted body wall to accommodate blood meal

  
• How do you identify a soft tick 


  No scutum

  mouthparts are not visible from the dorsal surface

  They don't swell much as they feed often but little

  
• What are the mouth parts of a tick 


  Palps - sensory organs (red)

  Chelicerae - puncture the skin

  Hypostome - tube for sucking host blood backwards - pointing teeth

  
• What is the palps 


  Sensory organ of a tick
• What is the chelicerae

  They puncture the skin
• What is the hypostome 


  Tube for sucking host blood backwards - pointing teeth
• How do ticks feed 


  They stand upright

  Chelicerae cut through the skin - pool of blood

  Hypostome inserted deep into the skin

  Mouthparts are cemented into place

  Tick continuously feeds - they inject saliva which contains anticoagulants and substances that decrease itching and dilate blood vessels which leads to a free flow of blood
• Describe the lifecycle of a tick

  Adult -> egg laying -> larvae -> nymphs -> adults

  
• How are hard ticks classified differently to soft ticks 


  Hard ticks are classified by the number of different hosts they attach to in their lifecycle
• Give an exmaple of a one host hard tick 


  Boophilus
• Give an example of a two host tick

  Hyalomma
• Give an example of a 3 host tick

  Ixodes
• What does a one host hard tick mean

  Every stage of development happens with feeding on one host
• What does a two host hard tick mean 


  Larvae and nymphs feed on one host and then adults feed on another
• What does a three host hard tick mean

  Each stage of development occurs on a different host
• Why are soft ticks not classified the same way as hard ticks

  Because they feed little and often on a range of different hosts
• What are the two types of disease transmission ticks do

  Trans-stadial transmission and Trans-ovarial transmission
• What is trans-stadial transmission 


  The infectious agent is ingested during feeding by larvae. Passed from host to host as the tick develops from a nymph to an adult. Not passed on to the next generation!!
• What is trans-ovarial transmission 


  Infectious agent is passed from one generation to the next through the egg e.g. Babesia spp
• What is an example of a species which does trans-ovarial transmission 


  Babesia
• What 3 host tick is of uk importance

  Ixodes
• Does ixodes have a wide host range

  Yes
• In animals Ixodes is a vector for what diseases 


  Bovine Babesiosis

  Louping ill

  Tickborne fever

  Pyaemia
• In people what is Ixodes a vector for

  Lyme disease
• What is the main species of ixodes tick

  I. Ricinus
• What is the name of the dog specific ixodes tick 


  Ixodes Canisuga
• What is the name for the hedgehog and others specific ixodes tick

  Ixodes Hexagonus
• What is the name for the cattle specific ixodes tick and is it common


  Haemophysalis

  Uncommon
• What is another rare ixodes tick

  Dermacentor spp
• What is the optimum time for ixodes ticks 


  spring and autumn

  high humidity in matted vegetation
• How much time of the year does an ixodes tick spend feeding 


  A few days
• Is the ixodes tick soft or hard

  Hard
• How many hosts does the ixodes tick have

  3
• How long is the lifecycle of the ixodes tick

  3 years
• Why is spring and autumn the prime time for ixodes ticks 


  Because the temperature and humidity is higher which speeds up development - less in summer because it is too dry and less in winter as it is too cold