DANGEROUS VENOMS: Australian Paralysis Tick
What is it?
The Australian Paralysis tick (Ixodes holocyclus) is a bloodsucking external parasite that is a dangerous threat to both humans and animals. Only the female ticks engorge themselves on blood, thus they are the only threats. Males do not bite, but seek out females to mate with as soon as they moult. They die after fertilising females. Females are very small when they have not fed, but can swell to very large sizes (over 200 times its weight) while they are sucking blood from a host. A newly moulted female will attach itself to a host after 7-9 (up to77) days. After she has mated with a male (sometimes before) she will feed on the blood of the host in order to gain enough nutrients for the eggs. Adult females engorge for a period of 6-30 days, the total time depending on the temperature (cooler temperatures slow down the time period) before dropping off the host and laying her eggs, starting the cycle again.
How can I identify it?
There are two main ways to identify a Paralysis tick from other Australia ticks:
1. The first and last pairs of legs are distinctly darker than the two middle pairs of legs.
2. The anal groove forms a complete, though pear shaped, circle around the anus.
Paralysis ticks are often confused with the Brown dog tickIf you are unsure, it is best to take the tick into a vet or medical centre for identification. Always remove ticks instantly upon discovery.
Where is it found?
Luckily, the Paralysis tick is usually found in a 20 kilometre wide band following the eastern coastline of Australia, and is not spread throughout the rest of the continent. However, Australia’s east coastline contains the majority of Australia’s most densely populated regions, and so incidents of bites on humans, pets and livestock are relatively common. Ticks commonly infest bushland and areas of high rainfall, and they often latch onto animals and humans that are moving through these areas.
What are the symptoms?
The Australian Paralysis tick has nasty side effects for pets and livestock, but the symptoms of Paralysis tick bites in humans are far less serious. The kinds of effects caused by bites of Ixodes holocyclus vary in their frequency according to the type of host and whether the tick is at the stage of larva, nymph or adult.
Humans are most notably affected by local irritation, allergic reactions and tick-transmitted infectious diseases. Tick paralysis is possible but now uncommon. To cause systematic paralysis an engorged female needs to remain attached for several days. Due to increased awareness and medical advances there are few incidences where a tick goes unnoticed for long periods of time. Depending on the part of the body that gets bitten, different side effects can take place. For example, a tick buried above the eyelid can result in gross facial and neck swelling.
Domestic animals (pets and livestock) are most notably affected by tick paralysis. Allergic reactions and tick-transmitted infectious diseases are possible but rarely diagnosed. If left untreated, bites often result in death. The toxins in the saliva of the female ticks paralyse muscle tissue, particularly the skeletal muscles, respiratory muscles, laryngeal muscles, oesophageal muscles and the heart muscles.