Animal Species:Australian Paralysis Tick, Ixodes holocyclus

The Australian Paralysis Tick is considered the most medically important of the Australian tick fauna.  Its east coast distribution means it comes into contact with humans, their pets, live stock and native animals frequently. Although most cases of tick bite are uneventful, some can result in life threatening illnesses including paralysis, tick typhus and severe allergic reactions.

Australian Paralysis Tick

Photographer: Stephen L. Doggett © Stephen L. Doggett

Standard Common Name

Australian Paralysis Tick


Flattened from top to bottom, with and overall oval, seed-shaped body, the Australian Paralysis Tick has 6 legs as larvae and 8, like the rest of their arachnid relatives, as nymphs and adults. They tend to be light blue to grey in colour.

Size range

10 mm


Found along the east coast of Australia


The species is found throughout the year in a variety of habitats, particularly wet sclerophyll forests and temperate rainforest areas, across the humid coastal regions of eastern Australia.


Each life stage can be present throughout the year, although for the Paralysis tick, adults are more abundant in the spring and the early summer months, larvae in mid to late-summer, and nymphs during winter.

Feeding and Diet

The Australian Paralysis Tick requires hosts for growth and development.  Their natural hosts include bandicoots, kangaroos, possums, birds and some times even reptiles. Humans and domestic animals like dogs and cats are also used as hosts.  

Other behaviours and adaptations

To attach to a host the Australian Paralysis tick displays a behaviour referred to as 'questing'.  The tick climbs vegetation (not usually higher than 50cm off the ground) and waits, slowly waving its forelegs to and fro until it makes contact with its host. Usually, only female Paralysis Ticks use mammals and humans as their hosts. 

People think that they fall out of trees but there is no evidence to suggest this occurs.


Life cycle

The life cycle of the Australian Paralysis Tick consists of four (4) stages- egg, larva, nymph and adult. Each stage requires a host to complete its life cycle.

Danger to humans and first aid

Allergic reactions are the most serious medical condition associated with ticks. These reactions can vary from a mild itching with localised swelling to widespread swelling with pain to a severe and life threatening anaphylatic condition. Unlike with most other medical conditions associated with ticks, severe allergic reactions may occur with any tick stage. For people who develop severe allergic reactions, it is imperative that they must always avoid contact with ticks and avoid potential tick infested areas.

If bitten, seek immediate medical attention.



What does this mean?

Chris Hosking , Interpretive Officer
Last Updated: