By Laurie Sullivan
Spring’s arrived in the Southern Hemisphere and that means the beginning of the danger period for ticks. But, adult ticks are about in gardens, parks, fields, and forests during the coming autumn months in the Northern Hemisphere, too.
Unlike buzzing mosquitoes in the air, silent ticks in the grass present such a low-profile disease risk as to be almost invisible. Indeed, some are the size of a pin head and their saliva has anaesthetic properties: Often you won’t feel a tick attach itself, which is why they go unnoticed.
But, their size belies their potential for transmitting diseases, or causing a potentially severe allergic reaction, to their two- and four-legged victims. They can transmit a long list of diseases –some potentially fatal – while just the bite may result in severe tick paralysis.
Along with an anaesthetic, tick saliva also contains a substance which can trigger mammalian meat allergy in some people. The allergy can bring on life-threatening anaphylaxis after the person later eats red meat or other animal-derived products, such as milk or gelatine.
TICKS A GLOBAL HEALTH RISK
Ticks are arachnids (8 legs) and they’re present almost everywhere – in both tropical and temperate climates. They’re among the most common causes of serious illnesses involving fever for travellers in sub-Saharan Africa.
In Australia, ticks are known to transmit diseases such as Rickettsioses and Babesiosis. The presence of Lyme disease in Australia has been the subject of much heated debate and recently an expert panel suggested that a pathogen that causes a ‘Lyme-like illness’ is present here rather than Lyme disease.
But, there’s no doubt Lyme disease is present in Europe and North America, with spring and summer being the peak seasons. Thousands of people in the USA (and more recently in Canada) contract it each year and many are left with its debilitating long-term effects. Other exotically named and potentially severe diseases like Anaplasmosis, Babesiosis, Ehrlichiosis, Rocky Mountain Spotted Fever, Tickborne relapsing fever, Tularemia, and 364D Rickettsiosis are also transmitted by ticks in North America.
In Europe, Lyme occurs in eastern and central countries, while the rarer (but often-fatal) Crimean-Congo haemorrhagic fever is found in southern and eastern regions – particularly in the former Soviet bloc countries. Most common of all is Tick-borne encephalitis (TBE), which is found across much of the Continent and is increasing its geographic range. (While there’s a vaccine for TBE for people at long-term risk, the best way for travellers to avoid a tick-borne disease is simply to avoid ticks.)
DEBATE OVER TICK REMOVAL
Preventing ticks from climbing aboard in the first place is important, but so is removing them quickly and effectively after they latch on. In fact, with many tick-borne diseases, infection doesn’t occur until the tick has been attached for more than 24 hours.
So, what’s the best way to remove a tick? Experts are divided.
The conventional wisdom is to pluck them off using tweezers. Certainly, that’s the advice of health authorities in North America and Europe.
But, in Australia, using tweezers may only make things worse, according to Sydney entomologist, Dr Cameron Webb*, who has written extensively on the public health risks posed by ticks and other arthropods in Australia.
“Recently there’s been a debate over the merits of killing the tick in place or removing it using tweezers, which is the recommended method in many parts of the world,” Dr Webb told the Travelvax Report.
“Forcibly removing ticks is correct for the species in the Northern Hemisphere, but they are not associated with tick paralysis or the potentially severe allergic reactions caused by the Australian Paralysis Tick (Ixodes holocyclus), the main tick species in Australia.
“Anything that agitates a tick is likely to see it inject its toxins. In fact, using tweezers may only increase the severity of any allergic reaction.
“And, if you are not experienced at doing it, you may only manage to squeeze the toxic contents of the tick’s gut into the wound.”
Similarly, dabbing a tick with methylated spirits, nail polish, alcohol, or petroleum jelly may eventually kill it – but only after it has injected saliva and toxins into the wound or onto the skin.
In the past, the use of the contact insecticides, such as creams containing permethrin, which are typically used to treat scabies, have been recommended. But, again, death isn’t instantaneous.
So, Australia needed a different approach.
There’s growing consensus among Australian experts that killing attached ticks using the same aerosol ‘freezing’ sprays used to treat warts may be best way to minimise the risk of severe allergic reactions.
These ether-containing sprays are available from pharmacies and they rapidly kill the tick in place, minimising potentially serious reactions. Once killed, the tick should be allowed to fall out naturally.
To end the confusion, Dr Webb said clear guidelines – supported by research and clinical trials – are needed to determine which of the various tick removal techniques will prevent or minimise allergic reactions and the transfer of infections.
Developing these guidelines for Australia is now the focus of the recently formed Tick-induced Allergies Research and Awareness (TiARA) group.
You don’t have to be hiking in the wilderness to encounter ticks: they are found around homes and in local parks, too. If you’re spending time outdoors – especially in rural or forested areas – you can stop ticks form hitching a ride by:
– Walking in the centre of trails, avoiding wooded and bushy areas with high grass and leaf litter.
– Wearing long trousers and a long-sleeved shirt.
– Tucking trousers into socks.
– Using an insect repellent containing 20% or more of DEET (N, N-diethyl-m-toluamide), picaridin, IR3535, or oil of lemon eucalyptus.
– Soaking clothing, boots, socks, pants and your tent, with a solution of permethrin. (The contact insecticide is safe and easy to use, and continues to be effective even after treated items are washed several times.)
DO A TICK CHECK – EVERY NIGHT
Of all prevention measures, the most important is an end-of-day body scan of yourself, your partner, and children using a hand-held or full-length mirror to view all parts of your body.
Parents should check for ticks under kids’ arms, in and around the ears, inside the navel, behind the knees, in the groin area, around the waist, and especially in the hairline.
There’s a right and wrong way to remove ticks (north of the equator at least). Here are some dos and don’ts:
DO – Use fine-tipped tweezers or a purpose-made tick remover, grasp the tick from the side (rather than from above) and as close to the skin’s surface as possible.
DON’T – Grip the tick along its length, as you are more likely to squeeze the contents of its stomach into the bite or onto your skin.
DO – Pull upward using steady, even pressure.
DON’T – Twist the tick. You’re more likely to cause its mouth to break off and remain in your skin. (While it is best to remove the tick intact, leaving behind the tick’s mouthparts isn’t a major concern. Just make sure you keep the site clean to stop secondary infection)
DO – Thoroughly clean the bite area and wash your hands with soap and water or rubbing alcohol after completely removing all traces of the tick.
Read more about removing ticks.
While many tick-borne diseases can be successfully treated with antibiotics, testing can be inconclusive, resulting in delays in identifying the illness. In turn this can delay a start to effective treatment and mean a longer recovery period.
Recovery can take many months: Some people never fully regain their former health.
If you develop a rash or fever within 28 days of removing a tick, see your doctor and be sure to mention the tick bite and where and when you were bitten.
For more information on the potential health risks for international travel, call Travelvax Australia’s free travel health advisory service on 1300 360 164.
* Dr Webb is based at the Department of Medical Entomology, Pathology West – ICPMR Westmead & the University of Sydney. You can follow him on Twitter @Mozziebites