TICKS IN THE GRASS

You may have noticed recently that Scotland Island seems to have heaps of small, itchy 'grass ticks'. Our two year old son, Alec, came in from playing down near Elizabeth park a few weeks ago with about 20 of them attached to his chest and under his arms. A lot of other people were getting the scratchies too.

Some tick bites can cause problems so it is useful to understand how to reduce the risks.

What are ticks

Ticks are blood-sucking external parasites. They are related to scorpions and spiders except that ticks have no separate head (the apparent "head" is just scary-looking mouthparts).

Although Australia has many kinds of ticks, the most common tick biting Scotland Islanders is the Australian paralysis tick (Ixodes holocyclus). It is found all along the east Australian coast and as far away as New Guinea, Indonesia, and India.

Life cycle

The Australian paralysis tick is a 'three stage' tick, comprising larva, nymph, and adult. Each stage feeds on you or some other animal, then drops off to grow into the next stage. The 'grass ticks' that got our son Alec are the larva or nymph stages of the paralysis tick.:

Larvae About the size of a full stop (.). Can live without feeding for as long as five months. Once larvae attach they suck blood for 4 to 6 days before dropping to the ground and moulting into nymphs.

Nymphs About the size of this asterix *. Can live without feeding for up to nine months!. They reattach to a host and party on, engorging for 4 to 7 days, then fall off. After a few weeks nymphs moult into adults.

Adults The adults cause the most problems. The female can engorge to nearly the size of the nail on your little finger. It feeds for 6 to 21 days (unless you tell it to piss off). Then, after an exciting life of sucking peoples groins and travelling to new places, it drops to the ground, lays 3000 eggs, and dies. The eggs hatch into larvae and the life cycle begins again.

Common hosts

Some ticks exclusively feed off a single host (for example, the cattle tick). However, the Australian paralysis tick feeds on almost any warm-blooded animal. When a tick attaches itself to feed, it buries its mouthparts deeply into your skin. Before you, earlier stages of the tick may have already fed off a possum, your dog or cat, a bird or even your neighbour!

Toxic effects

Paralysis

The engorging adult female paralysis tick secretes a neurotoxin in its saliva that can cause progressive, and occasionally fatal, paralysis (as seen in wobbly dogs). In warm weather this secretion commences on about the 3rd day of attachment and peaks on the 5th and 6th day. The symptoms of tick poisoning are muscle weakness or paralysis and a general feeling of not being well (not to be confused with getting drunk). Sometimes there is difficulty swallowing. In severe cases the patient has difficulty breathing.

Swelling

Some people get a severe hypersensitivity reaction in the area of the bite. I know of a bloke whose face swelled up like an out-of-control pumpkin. More usually, people get smaller, local irritations to tick bites.

Homoeopathic ledum, or anti-itch ointment based on nettle, aloe or tea tree, can help relieve local irritation.

Lyme disease

There have been concerns that Australian paralysis ticks may carry a bacterium that causes lyme disease (associated with ticks in the USA). Most people would probably have heard of lyme disease by now. Symptoms vary, so see your doctor if you are concerned, especially if pregnant or nursing.

Tips for prevention of tick bites

Here are some methods from the National Parks and Wildlife Service, and TAGS (Tick Alert Group Support) to reduce the risks:

Regularly maintain your yard

The engorged female of the paralysis tick prefers to lay its eggs in sheltered spots that are not prone to drying out. These include under stones and clods of soil, or crevices of walls and cracks of wood near the ground. The newly hatched larvae or climb onto grass and shrubs and wait until a suitable host passes. It's a good idea to keep the lawn short around your barbecue and along pathways. Ticks seem to like lantana. So get rid of lantana if possible.

Wear full covering

When in the scrub, wear long pants tucked into socks, a hat, and long sleeved shirts, etc. Light coloured clothes improve your chances of seeing a crawling tick. An insect repellent might help.

Always do a tick check

Check your pet regularly. If you've been in tick areas check your family (undressed is easiest) under arms, scalp etc...

Removing ticks

According to TAGS (Tick Alert Group Support) you should simply pull the tick out with steady pressure. Use fine point tweezers if necessary. It might not do much good to attempt to kill the tick with metho or kero, etc. This may cause the tick to inject more toxins, or may irritate your own skin. Try to get the 'head' out. If it stays in the skin it will not inject any more toxins once the body is removed, but it may cause a foreign body reaction similar to a splinter.

Tiny ticks (grass ticks) are best removed by soaking for 20 minutes in a warm bath with 1 cup of bicarb soda added.

Rick Noble


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