The cattle tick (Rhipicephalus microplus) is an important external parasite of cattle although other animals such as horses, buffalo, sheep and camelids can be affected too. Cattle ticks are found widely in northern Australia from northern parts of Western Australian and the Northern Territory, eastern and northern regions of Queensland and into northern New South Wales. In Queensland there is a demarcation between the tick free zone and the tick infested zone and reports of infestations in the free zone must be reported to Biosecurity Queensland.
The cattle tick is classified as a single-host tick because it lives its parasitic stages on one host. The time spent on the host is about 21 days. During this time the immature or nymphal stages feed on blood and gradually develop and grow. The female ticks engorge with blood then drop off onto pasture and lay up to 3000 eggs. The eggs hatch to release the larval stages which infest the next host. Larvae need to infect a new host or they will die and they are sensitive to climatic conditions of temperature and moisture but they can survive for up to two months in summer and as long as seven months in winter. Over wintering larvae are responsible for the rise in tick numbers in the following spring. It is important to note here are other tick species that affect cattle such as scrub or bush ticks and in some regions, paralysis ticks. It is important to be able to tell the difference between them because treatment and control can be different for the other types of ticks.