Paralysis Ticks

Paralysis ticks (Ixodes Holocylus) are a parasite which feed on the blood of mammals.  Their natural hosts are native wildlife such as bandicoots.  Occasionally a paralysis tick will attach to a pet or other domestic animal.  During feeding the paralysis tick releases a toxin called holocylotoxin which can cause a life threatening paralysis.

Ticks have a complex lifecycle which requires them to feed from 3 hosts before they are mature and Females are able to lay eggs.

Eggs hatch into 6-legged larve, which search for a host, attach and feed for several days before dropping off and moulting to become Nymphs.  The nymphs then search for and feed from a host before dropping off and moulting to become an adult.  The adult female ticks search for a host, and feed for 4-10 days before dropping off and laying eggs.  Adult males search for adult females to mate with, and are occasionally seen as a small brown/black tick next to a female.

Once engorged, the adult female will lay around 4000 eggs in leaf litter, and the cycle begins again.  The whole cycle normally takes a year, but can occur more quickly if conditions are favorable and the ticks quickly find hosts.

Unengorged Larvae (6 legs)	Unengorged Nymph (8 legs)	Unengorged Adult (8 legs)	Engorged Adult (8 legs)
0.5 mm long, 0.4 mm wide	1.2 mm long, 0.85 mm wide	3.8 mm long, 2.6 mm wide	13.2 mm long, 10.2 mm wide

When a tick attaches to a pet, they wander over the body before attaching: most ticks will attach near the head, neck and shoulders of pets.  Ticks are quite mobile, and will climb trees and plants to wait to attach to a host.

Identifying paralysis ticks

Paralysis ticks may be differentiated from other common ticks (such as the brown dog tick and cattle tick) by its legs, which are clustered up near its head, never more than half way back along its body.  The front and back legs are dark brown, then middle two legs are a lighter color.  Ticks are normally coloured light grey, white or bluish grey (The male tick is a darker brown and because it doesn't feed stays small: only 2-4 mm in size).  Female ticks may also have brown tones and often have stripes along their body or other patterns, which can vary widely in different geographic areas.  Ticks are found along the Eastern Seaboard, as far south as Lake's Entrance in Victoria to North of Cooktown in Far North Queensland.

Adult female - No engorgement
Adult female - Early engorgement
Adult female - Moderate engorgement
Adult female - Full engorgement

The information on this page is based on personal experience and numerous references.  Some material including the images are from the excellent wikipedia article on Ixodes Holocylus