Ticks Flashcards
Ticks belong to what subclass?
Acari
How do ticks burrow into skin?
They use their Chelicerae to cut a hole in the skin and the hypostome enters hole and is held in by the backwards facing teeth.
Cement is produced by some ticks to hold the mouthparts in place.
How do ticks suck up blood?
The tick injects saliva (containing vasodilators, anticoagulant, immunosuppressive proteins, and possibly neurotoxin and pathogens) and sucks up blood.
What are the direct effects of ticks?
Inflammation at attachment site
Anaemia
‘Tick paralysis’
What is the indirect effect of ticks?
Biological vectors for protozoa/ bacteria/ viruses
What are the two main families of tick?
Ixodidae- hard ticks
Argasidae – soft ticks
Where do Nidicolous (endophilic) ticks live?
‘in the nest’ – when not feeding, the ticks stay in the host’s nest/burrow
Most argasic ticks are nidiculous, and have multiple nymph stages.
Where do Non-nidicolous (exophilic) ticks live?
When not feeding the ticks are in the open environment – these ticks may go ‘questing’ to find their host, but most just wait for a host to pass by. Each stage in the life cycle might have a different host species
What type of tick is Argas persicus? What does it transmit?
Argasidae tick it is the fowl tick
Can effect poultry and wild birds leading to anaemia, debilitation, loss of production and can transmit pathogens such as Borrelia anserina. Can feed on people too
When do Argas persicus feed?
Nymphs and adults feed at night rapidly for only 15-30 mins, then drop off. They also feed several times during each life stage.
Name some common hard (ixodidae) ticks
Ixodes ricinus (castor bean tick, wide range of hosts) Ixodes haxagonus (hedgehog tick, also found on dogs) Ixodes canisuga (Dogs and badgers) Haemaphysalis punctata (red sheep tick, found on ruminants and rabbits) Dermacentor reticulatus Rhipicephalus sanguineus (dogs)
What is the difference between an ornate and inornate tick?
Ornate ticks have festoons
How can you use the anal groove to identify ticks?
A tick with an anal groove in front of the anus = Ixodex
Define transstadial transmission
transmission between stages eg larva to nymph
Define transovarial transmission
Vertical transmission from mother to eggs
Why are soft ticks rarely mechanical vectors?
They rarely change host
What causes tickborne fever?
Anaplasma phagocytophilum – (a rickettsia)
Transstadial transmission
Causes fever, immunosuppression, occasional haemorrhagic syndrome
What bacteria causes lyme disease?
Borrelia spp (esp B. burgdorferi)
What does lyme disease look like in dogs?
90+% no signs
Rash (easy to miss)
Recurrent lameness, lack of appetite and depression
Is there a vaccination for lyme disease?
yes
What is louping ill?
Infectious ovine encephalomyelitis
Virus infects CNS, causes significant suffering in clinically affected animals
How is louping ill controlled?
No statutory control measures, disease control is voluntary, includes use of acaricides and licensed inactivated vaccine against the virus
What is Babesiosis and theileriosis?
Protozoa that parasitise the red blood cells of vertebrates, and can be transmitted transovarially as well as transstadially in ticks.
Name the important species of Babesia
Babesia bovis –Europe spread by tick Rhipicephalus sp.
Babesia divergens in Northern Europe spread by Ixodes ricinus, (causes disease in cattle, sometimes zoonotic).
Babesia canis in Southern Europe, spread by Dermacentor spp and Rhipicephalus spp.
Babesia microti worldwide in rodents, sometimes zoonotic, transmitted by Ixodes spp.
Babesia (now Theileria) equi tropical and subtropical countires, Dermacentor spp, Hyalomma spp and Rhipicephalus spp.
How can we control Ixodid ticks
Mainly dips, sprays, pour ons, collars, ear tags etc. to kill adults on domestic animals
Control of ticks on wildlife and in the environment not practicable (Controversially, mountain hares have been culled to reduce ticks on red grouse)
Remove ticks asap as most pathogens only transmitted after tick has been feeding for a while
Vaccination against tick borne infections (Lyme disease in dogs and Louping ill in sheep)
