Ticks

Question 1

Ticks belong to what subclass?

Answer 1

Acari

Question 2

How do ticks burrow into skin?

Answer 2

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.

Question 3

How do ticks suck up blood?

Answer 3

The tick injects saliva (containing vasodilators, anticoagulant, immunosuppressive proteins, and possibly neurotoxin and pathogens) and sucks up blood.

Question 4

What are the direct effects of ticks?

Answer 4

Inflammation at attachment site
Anaemia
‘Tick paralysis’

Question 5

What is the indirect effect of ticks?

Answer 5

Biological vectors for protozoa/ bacteria/ viruses

Question 6

What are the two main families of tick?

Answer 6

Ixodidae- hard ticks

Argasidae – soft ticks

Question 7

Where do Nidicolous (endophilic) ticks live?

Answer 7

‘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.

Question 8

Where do Non-nidicolous (exophilic) ticks live?

Answer 8

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

Question 9

What type of tick is Argas persicus? What does it transmit?

Answer 9

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

Question 10

When do Argas persicus feed?

Answer 10

Nymphs and adults feed at night rapidly for only 15-30 mins, then drop off. They also feed several times during each life stage.

Question 11

Name some common hard (ixodidae) ticks

Answer 11

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)

Question 12

What is the difference between an ornate and inornate tick?

Answer 12

Ornate ticks have festoons

Question 13

How can you use the anal groove to identify ticks?

Answer 13

A tick with an anal groove in front of the anus = Ixodex

Question 14

Define transstadial transmission

Answer 14

transmission between stages eg larva to nymph

Question 15

Define transovarial transmission

Answer 15

Vertical transmission from mother to eggs

Question 16

Why are soft ticks rarely mechanical vectors?

Answer 16

They rarely change host

Question 17

What causes tickborne fever?

Answer 17

Anaplasma phagocytophilum – (a rickettsia)
Transstadial transmission
Causes fever, immunosuppression, occasional haemorrhagic syndrome

Question 18

What bacteria causes lyme disease?

Answer 18

Borrelia spp (esp B. burgdorferi)

Question 19

What does lyme disease look like in dogs?

Answer 19

90+% no signs
Rash (easy to miss)
Recurrent lameness, lack of appetite and depression

Question 20

Is there a vaccination for lyme disease?

Answer 20

yes

Question 21

What is louping ill?

Answer 21

Infectious ovine encephalomyelitis

Virus infects CNS, causes significant suffering in clinically affected animals

Question 22

How is louping ill controlled?

Answer 22

No statutory control measures, disease control is voluntary, includes use of acaricides and licensed inactivated vaccine against the virus

Question 23

What is Babesiosis and theileriosis?

Answer 23

Protozoa that parasitise the red blood cells of vertebrates, and can be transmitted transovarially as well as transstadially in ticks.

Question 24

Name the important species of Babesia

Answer 24

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.

Question 25

How can we control Ixodid ticks

Answer 25

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)