Ixodes holocyclus
Ixodes holocyclus (Australian paralysis tick)
Phylum: Arthropoda
Class: Arachnida
SubClass: Acari
Genus: Ixodes
Species: holocyclus
Common Names
Australian paralysis tick
Taxonomy and Biology
Medium sized hard bodied tick. Adult female may reach 10 mm total body length.
Species Map
Small (Approx 20k) version
General: Venom Neurotoxins
Presynaptic neurotoxins
General: Venom Myotoxins
Uncertain, probably not present
General: Venom Procoagulants
Not present
General: Venom Anticoagulants
Not present
General: Venom Haemorrhagins
Not present
General: Venom Nephrotoxins
Not present
General: Venom Cardiotoxins
Not present
General: Venom Necrotoxins
Not present
General: Venom Other
Clinical Effects
General: Dangerousness
Severe envenoming possible, potentially lethal
General: Rate of Envenoming: Unknown but likely to be low
General: Untreated Lethality Rate: Lethality only likely in the minority of cases showing severe progressive flaccid paralysis
General: Local Effects
Variable; most cases cause local irritation, but not systemic effects, while those causing paralysis often cause minor or no local effects noticeable by the victim.
General: Local Necrosis
Does not occur, based on current clinical evidence
General: General Systemic Effects
General systemic effects unlikely; occasionally develop fever
General: Neurotoxic Paralysis
Can develop severe progressive flaccid paralysis
General: Myotoxicity
Not likely to occur (single case with mild myolysis reported)
General: Coagulopathy & Haemorrhages
Does not occur, based on current clinical evidence
General: Renal Damage
Does not occur, based on current clinical evidence
General: Cardiotoxicity
Does not occur, based on current clinical evidence
General: Other
First Aid
Description: First aid for Tick bites (paralysis ticks)
1. The primary purpose of first aid in envenoming is to prevent the systemic spread of venom from the site of inoculation, and limit any deleterious local effects of envenoming. In tick paralysis, neither of these two objectives is likely to be met by first aid, as by the time there is clinical evidence of envenoming the salivary venom has already attained widespread body distribution and the local effects are, in comparison, minor. Hence prevention of envenoming by avoidance of bites, and regular body searches while at risk, to expeditiously remove ticks, are of more value than first aid.
2. In the case of a person, usually a child, developing the early symptoms and signs of paralysis, first aid should be directed towards getting the child to medical care quickly, and maintenance of vital functions, if imperilled. Particularly watch for developing bulbar and respiratory paralysis, keep the patient fasted, and nurse on the side to avoid the chance of aspiration of vomitus.
3. If there is any impairment of vital functions, such as problems with respiration, airway, circulation, heart function, these must be supported as a priority. In particular, for bites causing flaccid paralysis, including respiratory paralysis, both airway and respiration may be impaired, requiring urgent and prolonged treatment, which may include the mouth to mask (mouth to mouth) technique of expired air transfer. Seek urgent medical attention.
4. Do not use Tourniquets, cut, suck or scarify the wound or apply chemicals or electric shock.
5. If there is any evidence of developing paralysis, avoid peroral intake, absolutely no alcohol. No sedatives outside hospital. If there will be considerable delay before reaching medical aid, measured in several hours to days, then give clear fluids by mouth to prevent dehydration.
6. If there is any evidence of significant envenoming, such as difficulty walking or signs of paralysis, the patient should be transported as quickly and as passively as possible to the nearest place where they can be seen by a medically-trained person (health station, dispensary, clinic or hospital).
7. If the tick is present, DO NOT ATTEMPT to kill it. Avoid pressing the tick's body as more venom might be discharged. If a fine pair of forceps (tweezers) are available, remove the tick by holding the proboscis (mouth-parts) and gently pulling. Usually the mouth-parts come away intact and there will be no inflammation, but it is sometimes necessary for a medical practitioner to cut the embedded mouth-parts out of a small portion of skin.
Patients with inaccessible ticks such as in the ear should be referred to a hospital.
Treatment Summary
Australian paralysis ticks can cause progressive flaccid paralysis requiring respiratory support for a period, if full respiratory paralysis. All ticks should be removed. Check cryptic areas especially, such as scalp and in ears. Paralysis may worsen for up to 48 hrs after all ticks removed. No antivenom is available.
Key Diagnostic Features
Progressive flaccid paralysis, often first manifest as ataxic gait.
General Approach to Management
All cases should be treated as urgent & potentially lethal. Rapid assessment & commencement of supportive treatment is mandatory. Admit all cases.
Antivenom Therapy
Antivenom therapy is no longer available.
No Antivenoms
Ixodes holocyclus (Australian paralysis tick)