Ticks are arthropods. They are blood-sucking parasites. They can feed on mammals, birds and reptiles. They transmit Borrelia (the bacteria which cause Borreliosis – Lyme disease/Lyme-like disease), Ehrlichia, Babesia, Rickettsia, Bartonella and other infections of unknown cause/origin.

They are generally divided into hard and soft ticks. The hard ticks belong to the class Ixodes and soft ticks to Argasidae.


Some of the common hard ticks of Australia include:

• Ixodes holocyclus (Queensland, New South Wales, Victoria)
• Ixodes australiensis (Western Australia and Tasmania)
• Ixodus cornuatus is common in South East Coast of New South Wales, Central Victoria and Tasmania.
• Ixodes tasmani is the common possum tick (Tasmania, Victoria, New South Wales, Queensland, South Australia, Western Australia)
• Ixodes vestitus is the numbat tick (Western Australia)
• Boophilus microplus is the common Australian cattle tick (Queensland, Northern Territory, Western Australia, Northeastern New South Wales)
• The Amblyomma triguttatum is the ornate kangaroo tick (Western Australia, Queensland, Northern New South Wales, Southwestern Western Australia)
• Aponomma auruginans is the wombat tick (Southeast Australia)

The Paralysis Tick

Ixodes holocyclus is the paralysis tick. It releases a neurotoxin which blocks the acetyl choline receptors in muscle causing paralysis. This can happen in small animals and children. It can also happen to adults in delayed fashion.

How Ticks Spread Infection

Ticks have a life cycle consisting of eggs – feed – larva (6 legs) – feed – nymph (8 legs) – feed – adult (8 legs) – feed – lay thousands of eggs and die. The male tick feeds on the female while they copulate. Male ticks are less dangerous than females as they are more likely to feed on females than hosts. Nymphs are asexual and smaller in size than adults. There are one-host ticks that spend all of their life cycle with one animal, two-host ticks have two animals as hosts and three-host ticks are the ones most dangerous to humans.

Click the image to the right to enlarge and view the tick life cycle.

This is an excellent video by the TickEncounter Resource Center (University of Rhode Island) on how infections are transmitted from a tick to its host.

DISTRIBUTION OF TICKS IN AUSTRALIA

The maps below show the main distribution of Ticks in Australia