ticks

Question 1

what is the lifecycle of a tick

Answer 1

1. engorged female lays from 1000 to 10000 eggs and then dies
2. larva hatch from egg and seeks host such as small animal
3. engorged larva shelters in grass and moults to nymph
4. nymph seeks host such as rabbit or dog
5. engorged nymph shelters in grass and moults to adult
6. adult female seeks a host such as a dog or cat, engorges with blood and mates before dropping off

Question 2

describe the structure and function of a tick’s mouthpart

Answer 2

• chelicerae cut a hole in the skin
• hypostome enters hole and is held in by backwards facing teeth
• cement is produced by some ticks to hold mouthparts in place
• tick injects saliva containing vasodilators, anticoagulant, immunosuppressive proteins, possibly neurotoxins and possibly pathogens
• tick sucks up blood

Question 3

what are the direct and indirect effects of ticks

Answer 3

Direct:
- inflammation at attachment site
- anemia
- tick paralysis (only if large quantities of neurotoxin injected)

indirect:
- biological vectors or protozoa, bacteria and viruses

Question 4

ks

what are the 2 different types of ticks

Answer 4

• hard bodied ticks = ixodid
• soft bodied ticks = argasid

Question 5

what are the 2 types of tick lifecycles

Answer 5

• nidicolous (endophilic) = 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
• non-nidiculous (exophilic) = when not feedig 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 lifecycle might have different host species

Question 6

describe the lifecycle of argas persicus

Answer 6

Question 7

list common tick species

Answer 7

• ixodes ricinus
• ixodes hexagonus
• ixodes trianguliceps
• ixodes canisuga
• haemaphysalis reticulatus
• rhipicephalus sanguineus

Question 8

how do you tell the differences between species of ticks

Answer 8

• ornate vs inornate (ixodes dont have festoons)
• anal groove (ixodes have anal groove in front of anus)
• head shape

Question 9

what is transstadial transmission

Answer 9

transmission between stages (have to have host infection to infect next generation)

Question 10

what is tranovarial transmission

Answer 10

vertical transmission via eggs (doesnt need host to be infected, larva are infected and infectious)

Question 11

discuss tickborne fever

Answer 11

• anaplasma phagocytophilum
• transstadial not transovarial
• fever, immunosupression, occasional hemorrhagic syndrome

Question 12

discuss tick pyaemia

Answer 12

• in lambs, 2-12 weeks old
• immunosuppressed by anaplasmosis
• staphylococcus aureus introduced through bite wounds, umbilicus, etc leading to abscesses anywhere including joints

Question 13

discuss lyme disease

Answer 13

main effects are through transmission of infection and or secondary infections
in dogs:
- 90+% no signs
- rash is easy to miss
- recurrent lameness, lack of appetitie and depression
- rarely kidneys, heart or nervous system disease
- vaccine for use in dogs

Question 14

discuss louping ill

Answer 14

• mainly cuases disease in sheep and grouse particularly in upland areas
• occasionally causes illness in people and other animals
• virus infects CNS and causes significant suffering in clinically affected animals
• no statutory control measures, control voluntary

Question 15

how do you control ticks

Answer 15

• dips, sprays, pour ons, collars, ear tags etc
• no practicible in wildlife
• remove ticks ASAP to prevent transfer of pathogens
• vaccinate against tick born infections (lyme and louping ill)