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Information about ticks

What are ticks?

Ticks are small eight- legged arthropods with mouth parts resembling a barbed sword, which they jab through their host’s skin when feeding on animal and human blood.

There are four distinct stages of a tick’s development from eggs to larvae to nymph to adults.

Between each stage ticks must have a blood meal. The whole cycle usually takes approximately a year from egg to adult. It is easy to confuse the different stages of a tick’s development for different species of tick.

Where are ticks found?

There are over 70 species of tick in Australia, and it is the paralysis tick, Ixodes holocyclus, that are found along the east coast from Lakes Entrance in Victoria to Cooktown in far north Queensland that are involved in most run-ins with humans.

Ticks, like many insects, occur in humid, moist bushy areas. Eggs are typically laid in leaf matter or mulch. Ticks are not very mobile but rely on passing animals to both feed on and transport them.

Ticks may appear to drop onto clothing after brushing past bushes or trees, or may fall from overhanging branches.

How ticks harm humans

Ticks aren’t just annoying; their bite has the potential to cause infections, paralysis and deadly allergic reactions as they do inject a toxin.

Dr Cameron Webb, who is a medical entomologist at Westmead Hospital and clinical lecturer at the University of Sydney, says the most common health risk from a tick bite is developing an allergic reaction, which is potentially serious. It’s not unusual to have a reaction, such as itching and swelling, around the bite, however some people will have a more significant reaction. One study conducted at Mona Vale Hospital in Sydney’s Northern beaches found that 34 of the 500 people who presented with tick bites suffered from anaphylaxis.

Tick-borne diseases occurring in Australia are Australian Tick Typhus or ‘Spotted Fever” (along the coastal strip of eastern Australia from north Queensland to Victoria) and ‘Flinders Island Spotted Fever’ (in Victoria, Tasmania and Flinders Island in Bass Strait).

Early symptoms of tick paralysis can include rashes, headache, fever, flu-like symptoms, and tenderness of lymph nodes, unsteady gait, and intolerance to bright light, increased weakness of the limbs and partial facial paralysis. At the site of the bite there may be a black scab or eschar

As the tick engorges on more human blood the tick paralysis symptoms may intensify including after the tick has been removed. Clinical diagnosis is confirmed by specific blood tests.

Tick typhus is treatable with antibiotics, although fatalities have been known to occur.

Rickettsia

A tick born-pathogen that causes a flu-like illness

Ticks and Lyme disease

Lyme disease is caused by a bacterium and has become the most common tick-borne disease in the world.

While there is little evidence that Lyme disease is caused by Australian ticks, there may be other germs carried by Australian ticks, which may cause an infection similar to Lyme disease.

Lyme disease causes a range of non-specific symptoms including fever, fatigue, headaches, myalgia, arthralgia, muscle and joint pain and sore and swollen lymph glands. These symptoms can occur within days, weeks or months of being bitten. A characteristic skin lesion, erythema migrans, may also appear within 3 to 30 days at the site of the tick bite. Lyme disease can be treated with antibiotics.

There is such a big risk associated with allergic reaction that protecting your self from that threat is also going to protect yourself from other pathogens.

How do people know if they have been bitten by a tick?

A tick bite usually looks like a small dark freckle with a scab, or mole, on the skin. A magnifying glass may be helpful to confirm a tick is present.

As ticks are very small and their bites do not usually hurt, ticks can easily be overlooked on the body, especially if the tick is in a sheltered spot. Ticks prefer soft skin and hairy areas. People may be unaware when they are bitten by a tick, as the tick can inject small amounts of saliva with anaesthetic properties so that the person cannot feel that the tick has attached itself. In addition to the bite being painless, often the person will not sense a tick moving on their skin. However, once it starts to feed, it becomes noticeable, enlarging as it becomes filled with blood and eggs.

Managing a tick bite when bitten in Australia

Australia has specific challenges, particularly around allergies, anaphylaxis, and mammalian meat allergy from bites from one particular tick (the Australian paralysis tick), and therefore has different recommendations for the safe management and removal of ticks than the rest of the world.

To safely manage a tick bite, it is recommended that if bitten by any tick in Australia, people should not disturb the tick, from the time it is found attached to the skin to when it is killed. Attached adult ticks should be killed in situ (where they are) by freezing them with ether-containing sprays to prevent allergic reactions to ticks. The dead tick should then be left to drop off. For ticks that can hardly be seen (nymph and larval ticks) it is recommended that a generous amount of permethrin cream is carefully dabbed or dropped onto the tick to kill the tick where it is. If the person cannot freeze the tick, leave the tick in place without disturbing it and seek urgent medical assistance to safely remove the tick. Safely managing the tick using the recommended methods in this factsheet should not be overly delayed, as a delay of several hours may increase the risk of contracting a tick-borne illness.

Current advice stresses the importance of establishing whether a person who has been bitten by a tick in Australia has an allergy to tick bites. Subsequent medical management of the patient with a tick bite is highly dependent on the whether the person has an allergy or not.

It is vital that anyone with a known tick allergy summon urgent medical attention as soon as they are aware of an attached tick and not attempt to remove it without medical help. For patients with known tick allergies, managing and removing the tick must occur in a hospital or emergency department in the event of anaphylaxis occurring when the tick is removed.

All bites from adult ticks need to be treated as if an anaphylaxis could result, as first adult tick bite anaphylaxis is not uncommon.

Anaphylaxis, including tick anaphylaxis, is a medical emergency. In Australia, anaphylactic reactions to tick bites have been fatal, but fatalities are uncommon. Crucially, people who have an anaphylactic reaction to a tick bite react only when the tick is disturbed. Tick anaphylaxis is only seen with bites from adult ticks. As such, tick anaphylaxis is very unlikely to occur when the tick is killed where it is with ether-containing sprays before it is removed (that is freezing it where it is).

Multiple tick infestations

For multiple tick infestations use a paralyzing topical cream or lotion such as, Permethrin, 5%, cream or lotion (usually for scabies), Lyclear 30g or Quellada Scabies Treatment 100ml, these are suitable for use on children. Apply from the chin down and wash off with warm soapy water 8-14 hours later, rinse thoroughly.

These treatments may also be applied to the scalp, neck, face and ears in children under 2 years of age, elderly or immunocompromised people.

Permethrin acts on nerve cell membranes of the tick and subsequent paralysis (Australian medicines Handbook, 2014).

If you have a tick allergy

If you have a known allergy or are experiencing a reaction for the first time, ASCIA recommends seeking urgent medical attention to kill and remove the tick (unless it has previously established that you can safely perform the process yourself).

Also those with a known tick allergy should have an action plan to follow if they are bitten, and carry an adrenalin auto-injector.

Avoiding ticks

Next time you’re going somewhere you might come across a tick, you can reduce your chances of becoming a host, and all that goes with it by:

References

Management of tick bites in Australia, Department of Health and Aged Care factsheet

Lydia Hales - Science communicator at Science in Public and freelance journalist

Dr Cameron Webb – Medical entomologist at Westmead Hospital and clinical lecturer at the University of Sydney

Australian Society of Clinical Immunology and Allergy (ASCIA)