• Scientific name

    Ixodes holocyclus (holocyclus meaning - complete circle)


    The Paralysis Tick is around 3.6-3.9mm (unfed) whilst a fully engorged female can be 13-14mm long.    At the larva stage the tick has 3 pairs of legs, at nymph and adult stage it has eight that originate from the front of it's body.  The Paralysis Ticks legs are very close to the head, it's forelegs and the hind leg pairs as an adult or nymph are relatively dark brown (especially the hind pair) while the middle two pairs of legs on an adult and nymph are white.  

    Identification is difficult when the tick is unfed compared to the Brown Dog Tick that is more easily identified due to it's pronounced basis capituli.  The Paralysis tick has very pronounced mouth parts and is yellowish-brown with black markings on it's body.  As it begins to feed, the body becomes distinctively grey.

    Life Cycle

    The life cycle of the Paralysis Tick has 4 stages, egg, larvae, nymph and adult. Each stage (apart from the egg) does not proceed to the next without a blood meal.  The time taken to complete the life cycle varies greatly and depends on humidity temperature and host availability however on average the entire life-cycle takes about a year to complete.  Warm and humid environments mean the tick develops through the stages quickly but the survival rate is lower, in colder climates the development is slower but the survival rate is high.

  • Eggs

    The female tick must feed prior to reproduction and egg laying. She will feed on a host for fully gorged adult female will lay up to 6000 eggs at a rate of up to 200 eggs per day, usually in moist leaf litter. She coats the eggs with a secretion that prevents dessication and attaches them to a piece of bark or leaf litter. They hatch between 40-110 days.


    The eggs hatch to the larval stage which harden for up to 44 days before embarking on their search for a host in a process called 'questing'. This stage is often called the grass tick or seed tick as they are often seen in long grass at the tips waving their forelegs in the hope of attaching to a suitable host as it passes by. Each stage must have a blood meal to complete the cycle.


    The Larvae drops off and molts where it gains an extra pair of legs and then begins it's search of another blood meal this stage takes from 19-44 days. The tick has no eyes and senses carbon dioxide and motion which alerts it to the presence of a host, the fore legs are contain sensors similar to antenae of other insects. Depending on temperature the nymph will feed for a few days and drop off and molt to become an adult.


    The Paralysis Tick requires 3 hosts to complete it's life cycle. The male Paralysis Tick seeks out a host in search of a female to mate and feed from and usually doesn't feed directly from the host. Once fully gorged the female will drop off and find a suitable place to lay her eggs. The female dies 1-2 days after the egg laying process is complete.


    The Paralysis Tick is mostly found on the East Coast of Australia. It will inhabit bush and scrub areas as well as domestic and commercial situations. Being the perfect parasite, the tick spends most of it's life on a host.

  • Food

    Each stage of the life cycle of a paralysis tick require a blood meal usually from a passing host such as a bandicoots, possums, dog, cat or any other animal. Once attached the tick will insert their mouthparts (hypostome) into the host and inject anti-coagulant and then begin their feeding. The hypostome has reverse barbs which make it difficult to remove. As they feed they pass unwanted fluid back into the host along with the toxins which cause the paralysis. 

    Common names

    The Paralysis Tick is sometimes called the Grass Tick or Seed Tick as it finds it's way to the ends of blades of grass in search of a suitable host. The common name Paralysis Tick comes from the fact that it can cause paralysis and even death to humans and is often fatal to domestic animals. It is said that a large number of deaths of children in the 1800's and early 1900's were misdiagnosed as infantile paralysis (polio myelitis) which was actually caused by the paralysis tick.

    There is a lot of confusion with this tick because of the difference in what it looks like from one stage to another.  Some of the names that people call the paralysis tick are:

    • Shower Tick
    • Scrub Itch Tick 
    • Grass Tick 
    • Seed Tick

    These names are attributed to the larval stage but they are still the Paralysis Tick.

    • Shellback Tick 
    • Bush Tick 
    • Dog Tick (except Brown Dog Tick)
    • Scrub Tick
    • Common Hardback Tick

    There are many more depending on the region of Australia that you come from but they are all the same tick.