Ticks cont.

Ticks cont.

1. life cycle - hard ticks

   • 1, 2, 3 host tick classification
     • depends on no of hosts during lifecycle
     • 1 host - each stage feeds and develops on 1 host
     • 2 hosts - larvae and nymphs feed on 1 host, adults on another
     • 3 hosts - each stage feeds and develops on a different host
   • 1 blood meal at each life cycle stage
   • Ixodes spp.
     • 3 host tick
     • most important in UK
     • wide host range
     • vector for human and animal disease
       • Lyme and babesiosis
     • found in kennels

2. life cycle - soft ticks

   • feed little and often
   • lots of hosts

3. disease transmission

   • trans stadial
     • parasite ingested during feeding by larva
     • passed from one host to the next
     • not passed to next gen
   • trans ovarian
     • infection passed from one gen to next
     • passed through egg

4. epidemiology

   • life cycle - 3 years
   • feed only a few days each year
   • most of time on ground
   • several thousand eggs
   • HIGH HUMIDITY NEEDED FOR TICK SURVIVAL
   • seasonal tick activity
     • spring and autumn
     • temp and humidity dependent
   • ticks overseas
     • brought into UK
       • quarantine kennels
     • Boophilis spp.
       • babesia vectors
       • warm climates
     • amblyonma spp
       • heart water and Q fever
       • rocky mountain spotted fever in S USA
     • soft ticks
       • argas spp
         • infect birds
         • warmer climes
     • can be active all year round

5. control

   • integrated parasite control
     • altering microclimate
       • burning - during dry period
     • starving - livestock removed
   • stock management
     • fencing
   • acarides
   • stock hybridisation
     • reistance heritability higher in humped breeds
   • vaccination
     • TickGuard in Oz
       • hidden antigens