^ Multiple Rhipicephalus sanguineus ticks on a dog, Northern Territory, Australia (photograph by Graeme Brown)
| Ixodes holocyclus |
Rhipicephalus sanguineus |
|
|---|---|---|
| Common Name | Paralysis tick | Brown dog tick |
| Colour | Slate grey, changes when fully engorged | Brown |
| Legs | 1st and 4th pairs of legs darker than middle pairs; legs extend from capitulum in straight lines | All 4 pairs of legs equally coloured; legs extend from capitulum contouring to side of body |
| Capitulum | Long | Short |
| anal groove | Encircles anus | Only encircles posterior half of anus and then extends caudally into a median groove |
| Festoons | No festoons | Festoons on caudal body margin |
| Distribution | Found on the east coast of the Australian mainland | This tick has a wide distribution throughout the world and is recorded from practically all countries between the latitudes 500 N and 350 S. Found mostly in northern parts of Australia but also inland areas of Qld, WA, NSW, Vic; introduced. |
| Hosts | Mammals, birds, some reptiles | Has a small host range with the dog the main host. |
| Pathogenicity | Tick paralysis syndrome | It is a vector for a wide range of infectious agents affecting dogs such as Haemobartonella canis, Hepatozoon canis, Babesia canis, Ehrlichia canis and E. platys. Of these Babesia canis at least, is found in Australia in the northern parts. Infection with Babesia canis may result in a symptomless carrier state or in disease ranging in severity from mild to severe and occasionally ending in death. |
| Lifecycle | A three host tick. When fully engorged [replete], the adult female drops off the host, and after 11-20 days starts to lay a batch of 2,000 to 6,000 eggs into moist vegetation over 16-34 days, and then it dies. On the ground, suitable warmth and high humidity required for development (eg moist leaf litter). The eggs can survive the winter. The egg hatches on the ground after a 49-110 day incubation. The hatched larva, known as a "seed tick", undergoes 7-44 days of "hardening" and then climbs vegetation (eg the tips of of leaves). It attaches to a passing host (the 1st), feeds for 4-6 days then drops to ground; over a further 19-41 day period it then moults to a nymph. The overall period in the larval stage (hatch to moult) is temperature dependent. It may, for example, take 20 days at 27.5 ° C and 40 days at room temperature (21 °C) but may extend to 36 weeks. Nymphs are very active and 5-6 days after moulting and readily attach to another host (the 2nd) after day 7-8 (up to 31 days). The nymph feeds for 4-7 days, then drops to the ground. Adults . After a further 3-11 weeks the nymph moults to become the adult male or female. Again the period is temperature dependent. may emerge from the nymphal stage from the 20 days at 24-27 °C to 53-65 days at 10-21 °C. Dry conditions also prolong this period and can actually kill nymph. The newly moulted adult female becomes increasingly active for the 1st 6-7 days. It seeks and attaches to yet another host (the 3rd) after 7-9 to 77 days. It engorges for a period of 6-30 days, the time being dependent on weather- slower when cold. Male ticks do not usually engorge rather they wander over the host feeding "attach" intermittently and searching for unfertilised females. | A three host tick. Female lays up to 4000 eggs; pre-oviposition period 3-83 days; incubation period 8-67 days; larvae engorge in 3-7 days; larvae moult in 6-23 days; nymphs engorge in 4-9 days; nymphs moult in 12-129 days; females engorge in 6-50 days, unfed larvae survive up to 253 days; unfed nymphs survive up to 183 days; unfed adults survive up to 568 days; under favourable conditions a life cycle may be completed in 63 days; in warm areas, several generations of ticks may be expected each year (Hoskins JD, 1991) |
| Dorsal Aspect |  |
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| Ventral Aspect | 
^ mouse over image to show major grooves |
^ mouse over image to show major grooves |
 ^ showing eggs (photograph by Graeme Brown) |