Invited Speaker Australian Society for Microbiology Annual Scientific Meeting 2018

Tick-borne infectious diseases in Australia. (#48)

Stephen R Graves 1
  1. Australian Rickettsial Reference Laboratory, Geelong, VIC, Australia

Tick bites in Australia can lead to a variety of illnesses in patients. These include infections, allergies, paralysis, auto-immune disease, post-infection fatigue and Australian multi system disorder. This talk is limited to infections.

There are 3 important ticks that bite humans and can transmit infections:

1. Ixodes holocyclus (paralysis tick) and related species I.tasmani (common marsupial tick) and I.cornuatus (southern paralysis tick).

2. Amblyomma triguttatum (ornate kangaroo tick).

3. Bothriocroton hydrosauri (southern reptile tick).

There are 2 important groups of human pathogenic bacteria transmitted by ticks in Australia:

a. rickettsial infections. These include Queensland Tick Typhus (Rickettsia australis), Flinders Island Spotted Fever (R.honei) and Australian Spotted Fever (R.honei subs. marmionii). Murine typhus (R.typhi) and Cat flea typhus (R.felis), are rickettsial infections transmitted by fleas, not ticks and Scrub typhus (Orientia tsutsugamushi), transmitted by mites, not ticks, also occur in Australia.

b. Q Fever caused by Coxiella burnetii. While normally transmitted to human via aerosols from infected vertebrate animals (eg cattle, sheep, goats), some ticks also carry this bacterium and can infect humans when they bite.

There are likely to be other, unknown human pathogens yet to be discovered in Australian ticks eg viruses, protozoa and other bacteria.