Ticks are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by feeding on the blood of mammals, birds, and sometimes reptiles and amphibians. The timing of the origin of ticks is uncertain, though the oldest known tick fossils are from the Cretaceous period, around 100 million years old. Ticks are widely distributed around the world, especially in warm, humid climates.
The Ixodidae are the family of hard ticks or scale ticks, one of the three families of ticks, consisting of over 700 species. They are known as 'hard ticks' because they have a scutum or hard shield, which the other major family of ticks, the 'soft ticks' (Argasidae), lack. They are ectoparasites of a wide range of host species, and some are vectors of pathogens that can cause human disease.
The Argasidae are the family of soft ticks, one of the three families of ticks. The family contains 193 species, although the composition of the genera is less certain, and more study is needed before the genera can become stable. The currently accepted genera are Antricola, Argas, Nothoaspis, Ornithodoros, and Otobius. The Argasidae are very common in South Asia, along with 96 other species of ticks, making South Asia the region with the highest biodiversity of ticks worldwide. Soft ticks are resistant to desiccation and can live for several years in arid conditions.
Ixodiphagus hookeri, the tick wasp, is an encyrtid wasp which lays its eggs into ticks. It seems to use a symbiotic bacteria, Wolbachia pipientis, to weaken the tick's immune system.
Ixodes is a genus of hard-bodied ticks. It includes important disease vectors of animals and humans, and some species inject toxins that can cause paralysis. Some ticks in this genus may transmit the pathogenic bacterium Borrelia burgdorferi responsible for causing Lyme disease. Additional organisms that may be transmitted by Ixodes are parasites from the genus Babesia, which cause babesiosis, and bacteria from the related genus Anaplasma, which cause anaplasmosis.
Amblyomma is a genus of hard ticks. Some are disease vectors, for example the Rocky Mountain spotted fever in Brazil or ehrlichiosis in the United States.
Rhipicephalus is a genus of ticks in the family Ixodidae, the hard ticks, consisting of about 74 or 75 species. Most are native to tropical Africa.
Ticks of domestic animals directly cause poor health and loss of production to their hosts. Ticks also transmit numerous kinds of viruses, bacteria, and protozoa between domestic animals. These microbes cause diseases which can be severely debilitating or fatal to domestic animals, and may also affect humans. Ticks are especially important to domestic animals in tropical and subtropical countries, where the warm climate enables many species to flourish. Also, the large populations of wild animals in warm countries provide a reservoir of ticks and infective microbes that spread to domestic animals. Farmers of livestock animals use many methods to control ticks, and related treatments are used to reduce infestation of companion animals.
Rhipicephalus hoogstraali is a tick found in Djibouti and Somalia. First recognized by Harry Hoogstraal as Rhipicephalus longicoxatus based on an incomplete published description, after discovery of the holotype of R. longicoxatus, it was described and named to honor Hoogstraal in 2009.
Amblyomma triguttatum, commonly known as the kangaroo tick, is a species of tick in the genus Amblyomma native to Australia, in Western Australia, parts of Queensland, and in New South Wales.
Ornithodoros savignyi, known as sand tampan, African eyed tampan or Kalahari sand tampan, is one of some 37 species in the genus Ornithodoros and is a soft tick with a leathery, mammillated integument, causing paralysis and tampan toxicosis, two unrelated conditions. The sand tampan is an ectoparasite on humans, their livestock and wild animals, including birds and bats. Occurring in semi-desert areas of Africa, Saudi Arabia and other parts of the Persian Gulf, India, Sri Lanka and into Asia, it is able to survive for lengthy periods without feeding, spending most of its life burrowed under sand or loose soil, often in wait for animals that rest or sleep under trees or in the lee of rocks, but also in places where people or their animals congregate such as marketplaces, places of worship, cattle kraals and village squares. The timing of its activity is geared to coincide with that of potential hosts, but hot sunny conditions are usually avoided. Because of its habit of feeding and dropping from its host, adult dispersal is limited, whereas larvae may remain attached to their hosts for several days. During its life cycle it will feed on multiple hosts between moults.
Amblyomma integrum is a hard-bodied tick of the genus Amblyomma. It is found in India and Sri Lanka. Adults parasitize various larger mammals such as buffalo and cattle, whereas nymphs and larvae use mostly larger and medium mammals. In Sri Lanka, tick was identified as an agent of human otoacariasis.
Amblyomma testudinarium is a hard-bodied tick of the genus Amblyomma. It is found in Indonesia, India, Japan, Thailand, Sri Lanka and Vietnam. Adults parasitize various larger mammals such as buffalo and cattle, whereas nymphs and larvae use mostly larger and medium mammals.
Dermacentor reticulatus, also known as the ornate cow tick, ornate dog tick, meadow tick, and marsh tick, is a species of tick from the family Ixodidae. It is the type species for the genus Dermacentor. D. reticulatus is an ornate tick. The female varies in size from 3.8–4.2 mm (unfed) to 10 mm when engorged after feeding. The unfed male is 4.2–4.8 mm long. D. reticulatus is found in Europe and Western Asia, generally in wooded areas.
The zebra tick or yellow back tick is a species of hard tick. It is common in the Horn of Africa, with a habitat of the Rift Valley and eastward. It feeds upon a wide variety of species, including livestock, wild mammals, and humans, and can be a vector for various pathogens. The adult male has a distinctive black and ivory ornamentation on its scutum.
Maria Vladimirovna Pospelova-Shtrom (1902–1991) was a 20th century parasitologist best known for her work delineating the biology and public health importance of ticks in western Asia and eastern Europe, contributing to the reduction of the incidence of tick-borne diseases, especially tick-borne relapsing fever.
Ixodes siamensis is an ixodid tick that is parasitic on mammals in Thailand.
Cosmiomma is a genus of ticks first discovered by Paul Schulze in 1919. It is monospecific, being represented by the single species Cosmiomma hippopotamensis. It was first described in 1843 by Henry Denny from specimens collected from a hippopotamus in Southern Africa, and has been called "one of the most unusual, beautiful, and rare tick species known to the world."
Paul Schulze was "the most important German tick taxonomist of the early 20th century." Between 1929 and 1937, he described 19 genera, 17 subgenera, 150 species and 150 subspecies of ixodid ticks. He was essentially an amateur taxonomist, working alone for most of his career, not consulting the major tick collections or collaborating with other tick taxonomists.
Natalia Aleksandrovna Filippova was a world authority on the taxonomy of mites and especially ticks. Her monographs on the identification, morphology, development, distribution and behaviour of the family Argasidae and the sub-families of Ixodinae and Amblyomminae are standard works on these important vectors of disease.
