Ticks inject a toxin that may cause local irritation or a mild allergic reaction, however, most tick bites cause little or no symptoms. In some cases however ticks can pose a serious threat to human health. Tick-borne diseases like tick paralysis and severe allergic reactions, while uncommon, can pose a serious health threat. 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, tenderness of lymph nodes, unsteady gait, 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. In some susceptible people, tick bite may cause a severe allergic reaction or anaphylactic shock, which can be life-threatening. If swelling of the face and throat causes breathing difficulties, seek urgent medical attention.
Recently a new syndrome known as “tick-induced mammalian meat allergy” has been described, whereby people bitten by the paralysis tick, which is found in Coastal Eastern Australia, can subsequently develop an anaphylactic reaction to consuming meats and animal by-products such as gelatine. This syndrome has also been described overseas.