Ticks in Australia

Ticks in Australia     

Ticks are obligate haematophagous ectoparasites (blood-feeding parasites, that live on the outside of their host) and are abundant in most continents. They are important vectors for the transfer of microorganisms causing disease in livestock and humans. They can feed on mammals, birds and reptiles. Globally they transmit Borrelia (the bacteria which cause borreliosis - also known as Lyme disease/Lyme-like disease, Lyme borreliosis or relapsing fever), Ehrlichia, Babesia, Rickettsia, Bartonella and other infections.

 

Ticks are arachnids, a subset of the arthropod family (insects and crustaceans are also arthropods), having a segmented body, jointed limbs and usually a chitinous shell that undergoes molting. They are also capable of inducing allergies, causing toxicoses and paralysis. 

They are generally divided into hard and soft ticks. The hard ticks belong to the class Ixodidae and soft ticks to Argasidae. They are listed below.

HARD TICKS (Ixodidae

  • Ixodes holocyclus­ -paralysis tick (Queensland, New South Wales, Victoria)
  • Ixodes australiensis (Western Australia and Tasmania)
  • Ixodus cornuatus -southern paralysis tick (South East Coast of New South Wales, Central Victoria and Tasmania)
  • Ixodes tasmani -common marsupial tick (Tasmania, Victoria, New South Wales, Queensland, South Australia, Western Australia)
  • Ixodes vestitus -numbat tick (Western Australia)
  • Haemophysalis bancrofti -wallaby tick (east coast of Australia)
  • Haemophysalis longicornis -bush tick (Eastern Australia-Queensland, NSW, some parts of Victoria Western Australia- between Walpole and Denmark
  • Rhipicehpalus sanguineus -brown dog tick (Eastern, Northern and Western Australia)
  • Rhipicephalus (Boophilus) australis (Australian cattle tick) (Queensland, Northern Territory, Western Australia, Northeastern New South Wales)
  • The Amblyomma triguttatum -ornate kangaroo tick (Western Australia, Queensland, Northern New South Wales, Southwestern Western Australia)
  • Bothriocroton auruginans -wombat tick (Queensland-NSW border to South Australia-Western Australian border and Tasmania)
  • Bothriocroton hydrosauri  -south reptile tick (Southern NSW, Victoria, South Eastern South Australia And Tasmania)


SOFT TICKS (Argasidae)

  • Argas persicus -poultry tick (mainland Australia)
  • Argas robertsi  -Roberts bird tick (Northern Territory and Queensland-not well studied)
  • Ornithodoros gurneyi  -kangaroo soft tick (Central Australia, Queensland, Western Australia, Northern Territory)
  • Ornithodoros capensis -seabird soft tick(nests of seabirds on islands and mainland –not well studied, reported along coast from Perth in Western Australia to Sydney, NSW)
Soft ticks can survive in caves and stay dormant for years if conditions are not favourable.  Humid temperate areas are not the only places where ticks are common.  Soft ticks (Argasidae) such as Ornithodorus  erraticus, O. sonrai, O. moubata, transmit relapsing fever Borrelia in Africa  (Table link-Borrelia genospecies ) and are endemic in dry, mountainous areas. Soft ticks (Argasidae) have a global distribution.
For additional information refer to the Ticks of Australia guide written by Stephen Barker & Alan Walker   


The Paralysis Tick

Ixodes holocyclus is the paralysis tick. It can cause paralysis by a neurotoxin released during tick feeding which blocks the acetyl choline receptors in muscle (Hall-Mendelin et al, 2011). Paralysis can occur in small animals and children, or in adults in a delayed fashion. Initial symptoms of tick paralysis may include unsteady walk, weakness of the limbs rashes, headache, fever, flu like symptoms, tenderness of lymph glands and partial facial paralysis (Morris et al 2003).  See Bushcare-Newsletter-Winter-2011.
In addition, the paralysis tick can transmit infections such as Queensland tick typhus (a Spotted Fever group rickettsiae).  Please refer to the table below that lists infections that are transmitted by Australian arthropods.

 

Pathogen

 

Human Disease

 

Vector

 

Location

 

Reference

 
 

Rickettsia

Rickettsia honei sub sp marmionii
  Australian Spotted Fever   Haemaphysalis novaeguineae   Eastern QLD
Eastern & Southern NSW
Victoria
Tasmania
South East SA
  Unsworth et al., 2007  
                     
  Rickettsia typhi   Murine Typhus   Flea-Ctenocephalides felis   Small areas in North East & South East QLD
Sydney
Greater Melbourne
South East SA
West Cast around Perth and Cape Range National Park
  Graves & Stenos, 2009  
                     
  Orientia tsutsugamushi   Scrub Typhus   Mites-larval “chiggers” Leptotrombidium deliense   Northern Australia   Graves & Stenos, 2009  
                     
  R.australis   Queensland Tick Typhus   Ixodes holocyclus, Ixodes tasmini   East Coast of Australia QLD, NSW, Victoria   Graves & Stenos, 2009  
                     
  Rickettsia honei   Flinders Island Spotted Fever   Bothriocroton hydrosauri   Victoria, Tasmania, SE South Australia, Southern NSW   Graves & Stenos, 2009  
                     
  Rickettsia grevesii   ?   Amblyomma triguttatum        Abdad et al., 2014  
                     
  Rickettsia felis   Cat Flea Typhus   Flea-Ctenocephalides felis       Abdad et al., 2011; Williams et al., 2011  
                     
  Coxiella burnetii   Q-fever   Ixodes holocyclus, Amblyomma triguttatum    QLD, WA, NSW, SA   Cooper et al., 2013; Tozer et al., 2014; McDiarmid et al, 2000  
                     
  Bartonella henselae   Bartonellosis, Cat Scratch Disease   Flea-Ctenocephalides felis; ticks?       Arvand et al., 2007  
                     
  Bartonella clarridgeiae   Bartonellosis, Cat Scratch Disease   Flea-Ctenocephalides felis; ticks?   Eastern Australia   Barrs et al., 2010  
                     
  Babesia microti   Babesiosis   ?   ?   Senanyake et al, 2012  
                     
  ?   Lyme-like disease   ?   ?   Stewart, 1982; McCrossin, 1986; Lawrence et al., 1986;
Wills & Barry, 1991; Hudson et al., 1994; Hudson et al., 1998
 
                     


How Ticks Spread Infection

Three host ticks have a life cycle consisting of eggs – hatch– larva (6 legs) – feed – nymph (8 legs) – feed – adult (8 legs) – feed – lay thousands of eggs and die (see diagram). The male tick usually feeds on the female while they copulate. Male ticks are less dangerous than females as they are more likely to feed on female ticks than hosts. Nymphs are asexual and smaller in size than adults. There are also one-host ticks that spend all of their life cycle with one animal and two-host ticks which have two animals as hosts.

Ticks in Australia - 3 host cycle 

Tick Bite Meat Allergy 

Tick saliva contains antigenic proteins to which the host immune system can react resulting in a localised skin reaction.  An allergic reaction which can be anaphylactic has also been described to red meat developed following tick bite. This allergic reaction appears to be elicited to a mucopolysaccharide galactose- alpha-1,3 galactose in tick saliva resulting in IgE production. If the person consumes red meat there is a delayed allergic reaction. (Commins et al, 2011). 
 
Clinicians when presented with a tick bite need to consider both potential allergic reaction and underlying infection.  Problems arise when the allergic reaction or symptoms have a delayed onset from time of tick bite.
 
       

The life cycle of Babesia microti

This is an excellent video by the Tick Encounter Resource Center (University of Rhode Island) on how infections are transmitted from a tick to its host.

 Distribution of Ticks in Australia
The maps below show the main distribution of 3 common ticks in Australia

Types and distribution of ticks in Australia

 

 

 

 

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Growing evidence of an emerging tick-borne disease that causes a Lyme like illness for many Australian patients

On 12 November 2015, the Senate referred the following matter to the Senate Community Affairs References Committee for inquiry and report:

The growing evidence of an emerging tick-borne disease that causes a Lyme‑like illness for many Australian patients.

 
Submissions should be received by 31 March 2016. The reporting date is 20 June 2016.
 
Nov 17, 2015

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