Ticks

Ticks are parasites that live off blood of humans and animals. Ticks get to blood by attaching themselves to the skin of their host with sharp mouthparts, piercing the skin and injecting saliva into the area to prevent blood clotting. In the case of the paralysis tick, it’s the transfer of the highly toxic saliva from that can have serious medical implications for the host.

Special thanks to Henry Lydecker for reviewing and contributing to this article:
HENRY LYDECKER | PhD Candidate
School of Life and Environmental Sciences | Faculty of Science
THE UNIVERSITY OF SYDNEY

In Eastern Australia, 95% of tick bites are due to the Paralysis Tick (Ixodes holocyclus), and most tick-borne illnesses are the result of a Paralysis Tick bite.

Photo credit: Ryan Wick via Foter.com / CC BY

This species may also be referred to as the grass tick, seed tick and bush tick depending upon the development stage: the egg, larvae (around 1mm and light brown in colour when not full of blood), nymph (around 2mm and pale brown) and the adults (4–5mm in length, without blood).

Tick life cycle (S.L. Doggett, Department of Medical Entomology, Westmead Hospital) as described above

Ticks are usually more likely to be found in more humid, less windy, more dense vegetation, more leaf litter, so avoiding these areas can be a way of dodging tick bites.

Unfortunately, bushwalks generally go through these habitats! Long sleeved shirts and pants are key for reducing the likelihood of tick bites, as well as insect repellent containing DEET or Picardin.

In addition the NSW governemnt website suggests:

• Tuck long pants into socks and long sleeved shirts in pants.
• Use light coloured clothing so that ticks are easier to spot.
• Check yourself regularly for ticks. Tick prone areas include back of the head and neck, groin, armpits and back of knees. Get a friend to check areas like your back that are hard to inspect, or use a mirror.
• After you get home from a trip, put all clothing in a hot dryer for at least 10 minutes to kill any remaining ticks.

Although tick bites are not uncommon in Australia, there has been very little medical research into tick-borne illnesses or best practice in tick removal to date. Here’s the best of our knowledge so far!

For most people, tick bites cause local swelling, redness and itchiness at the bite site, but generally pose no medical problems as long as the tick is removed quickly.

On rare occasions, people development allergic reactions (and even anaphylaxis) to ticks. While rare, allergic reactions can be serious, so consult your doctor if you have a history of allergic reactions with tick bites, or if you are concerned about possible allergic reactions.

There are two main tick-borne diseases that can occur in Australia, Queensland Tick Typhus and Flinders Island Spotted Fever. Very occasionally, ticks bites may lead to tick paralysis.

Queensland Tick Typhus
Queensland Tick Typhus is is a condition caused by a bacterium Rickettsia australis, and is transmitted by the Tick species Ixodes holocyclus and Ixodes tasmani. A blood test is the clinic confirmation of the condition, and is treated with antibiotics (although fatalities have occurred rarely).

Symptoms include:

• Rashes
• Eschars
• Headaches
• Fever
• Flu-like symptoms
• Lymph node tenderness

Flinders Island Spotted Fever
Flinders Island Spotted Fever a condition associated with the bacterium Rickettsia honei, and is also transmitted by ticks.

Symptoms include [note]Stewart RS Flinders Island spotted fever: a newly recognised endemic focus of tick typhus in Bass Strait, part 1: clinical and epidemiological features. Med J Aust 1991;154:94–9; Graves SR, Dwyer BW, McColl D, McDade JE Flinders Island spotted fever: a newly recognised endemic focus of tick typhus in Bass Strait, part 2: serological investigations. Med J Aust 1991;154:99–104[/note]:

• Fever
• Headache
• Myalgia
• Transient arthralgia
• Maculopapular rash
• Cough (in some cases)

Tick paralysis
Very occasionally, ticks bites may lead to tick paralysis, an extremely rare, but severe conditions. In the few known cases, tick paralysis has been have recorded in the very young, very old, or otherwise immunologically impaired.

Early signs and symptoms of tick paralysis to include:

• Rashes
• Headache
• Fever
• Influenza like symptoms
• Tenderness of lymph nodes
• Unsteady gait
• Intolerance to bright light
• Increased weakness of the limbs
• Partial facial paralysis

PET OWNERS BE CAREFUL: Tick paralysis is serious (often fatal) in dogs. Owners walking their dogs near the bush need to check pets carefully afterwards for ticks.

Lymes disease
Lymes disease is a seroius tick-borne disease that if left untreated, the infection can spread through the bloodstream to the brain and heart.

Several species of ticks in Africa, Asia, Europe, and North America are known to carry and transmit species of Borrelia bacteria that are known to cause Lyme disease in humans.

Australian ticks like the Paralysis tick have been suspected as possible vectors of Lyme disease, but multiple studies have failed to find any Borrelia species bacteria in these ticks. The only known species in the Borrelia genus that occurs in Australia is only found in one species of Australian tick that is only known to bite Echidnas [note]Loh, Siew-May, et al. “Novel Borrelia species detected in echidna ticks, Bothriocroton concolor, in Australia.” Parasites & Vectors 9.1 (2016): 339[/note]. This species of bacteria is not in the same group as those known to cause Lyme disease, so it is unlikely to be a health threat.

There are, however, advocacy groups in Australia (Primarily the Lymes Disease Association of Australia) that acknowledge Lymes Disease (or Lyme-like diseases) to occur in Australia, and advocate for Lymes Disease to diagnosed and treated accordingly.

Many health workers and public health researchers believe that Queensland Tick Typhus and Flinders Island Spotted Fever are the most common tick-related health issues in Australia. It is widely suspected that patients who believe they have Lyme’s disease actually have a subclinical infection of tick typhus (although there is currently no research to support this).

Regardless of the label, tick-borne diseases can be serious. Consult your health professional immediately if you have any concerns following a tick bite.

Tick-induced meat-allergies
A peculiar meat-allergy has also emerged in recent years, affecting people found in coastal Eastern Australia. The tick-induced mammalian meat allergy (MMA) has seen some people bitten by paralysis ticks to develop a severe allergic reaction to meat products and sometimes dairy and gelatine. If you believe you have developed red meat allergy, consult your doctor for referral to a specialist.

TRAVELLING ABROAD?
If you travel abroad, consult local guides for information about ticks and tick-borne diseases that are relevant there. If you fall sick upon returning to Australia, make sure to discuss your travel with your doctor.

The NSW government health website suggests the following for tick removal:

“Ticks should be removed as soon as possible using fine tipped forceps or fine surgical scissors. Hold the tick as close as possible to the surface of the skin and pull with steady pressure. Avoid squeezing the body of the tick during removal. If you are unable to do this, see your doctor to remove the tick. Do not use methylated spirits, nail polish remover, alcohol, petroleum jelly or any other products on ticks prior to removal as it will cause the tick to inject more toxins.
Note: In individuals with a history of allergic reactions to tick bites, ticks should be removed as soon as possible, but only by a doctor and where resuscitation facilities are readily available”.

Photo credit: https://www.cdc.gov/ticks/removing_a_tick.html

After removal, apply antiseptic cream to the bite area. If tick removal is difficult, or you begin to suffer rash, swelling, signs of infection, muscle weakness in the bite site area or flu like symptoms, seek medical attention urgently.

DO NOT:

• Do anything to irritate the tick because this makes it harder to completely remove it (e.g. squeezing, rubbing, scratching).
• Grasp the tick by the body.
• Apply methylated spirits, kerosene or fingernail polish.
• Use a lighted match, or cigarette.

NOTE

The Australasian Society of Clinical Immunology and Allergy recommends killing ticks by freezing them off using ether-containing sprays (e.g. Wart-Off Freeze®, Elastoplast Cold Spray®). This method is still in the research and development phase, and while promising, is not currently recommended by the NSW government health website.

A recent literature review published in early 2017 concludes [note]Coleman N and Coleman S. Methods of tick removal: A systematic review of the literature. AMJ 2017;10(1):53–62[/note]:
“The best method is to remove the tick as soon as possible after it is detected, using either fine-tipped tweezers or a reputable commercially produced tick removal tool to pull the tick away from the site of attachment……Other methods of removal, such as freezing, while promising, have not yet been scientifically validated.”

So the conclusion is: stick to tweezers, until other methods are validated.