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Haemaphysalis spp


Few of the 166 species of Haemaphysalis parasitize livestock, but those that do are economically important in Eurasia, Africa, Australia, and New Zealand. Some haemaphysaline parasites of wild deer, antelope, and cattle have adapted to domestic cattle and, to a lesser extent, to sheep and goats. Others, originally specific for various wild sheep and goats, have adapted chiefly to the domestic breeds of these animals. A few African species that evolved together with carnivores now parasitize domestic dogs. Immatures of species that parasitize livestock generally feed on small vertebrates, but there are a few notable exceptions. All Haemaphysalis spp have a 3-host life cycle. They are small (unfed adults <4.5 mm long), brownish or reddish, and eyeless. Most have very short mouthparts. Different species cause tick paralysis and are vectors of the agents that cause Q fever, tularemia, and brucellosis, and of Theileria orientalis, T ovis, Babesia major, B motasi, B canis, Anaplasma mesaeterum, etc.

H punctata is widely distributed where sheep, goats, and cattle feed in certain open forests and shrubby pastures from southwestern Asia (Iran and former USSR) to much of Europe, including southern Scandinavia and Britain. Immatures infest birds, hedgehogs, rodents, and reptiles. In addition to transmitting Anaplasma and Babesia spp, different H punctata populations are infected by Russian spring-sumer encephalitis virus, Tribec virus, Bhanja virus, and Crimean-Congo hemorrhagic fever virus.

H sulcata adults parasitize livestock (chiefly sheep and goats) from northwestern India and southern former USSR to Arabia, Sinai, and southern Europe. H parva adults parasitize these hosts from southwestern former USSR and the Near East to the Mediterranean area (but not Egypt). Immature H sulcata are especially common on lizards, but the range of hosts of larvae and nymphs of both species is similar to that of H punctata.

H longicornis is a parasite of deer and livestock in Japan and northeast Asia; there is a bisexual form (race) in southern areas and a parthenogenetic race in northern areas. The latter has been introduced into Australia, New Zealand, and the Pacific islands, where it preserves this unusual reproductive ability. Immatures usually parasitize small mammals and birds but may also feed on livestock; heavy population densities may become serious pests of deer and livestock. This tick is the chief vector of Theileria orientalis and also transmits Babesia ovata, B gibsoni, and the agents of Q fever, Powassan encephalitis, and Russian spring-summer encephalitis. Larval feeding causes acute dermatitis in humans.

Other Eurasian haemaphysalines of livestock are H inermi (lowlands from northern Iran and southwestern former USSR to central and southeastern Europe to Italy), H pospelovashtromae (mountains of southern former USSR and Mongolia), H kopetdaghicus (Caspian Sea area, mountains of former USSR, and Iran), and H tibetensis, H xinjiangensis, and H moschisuga (China).

Of the several Haemaphysalis spp parasitizing livestock in southeast Asia, 3 are especially noteworthy: H bispinosa ranges to Pakistan, Bangladesh, Nepal, Bhutan, Sri Lanka, and Malaysia, and transmits Babesia spp to cattle, sheep, and dogs; H spinigera is the chief vector of Kyasanur Forest disease virus in humans in Karnataka state, India; and H anomala ranges from the Nepal lowlands to Sri Lanka and the mountains of northwestern Thailand.

In temperate Asia, 18 other haemaphysalines parasitize livestock: 9 high in the Himalayas and outlying mountains, and 9 in northeastern Russia, Korea, and Japan. Yak and yak-cattle hybrids are among the livestock hosts of Himalayan haemaphysalines. Several Himalayan species appear to prefer sheep and goats.

In sub-Saharan Africa, 4 haemaphysalines infest livestock in highland forests or lowland, humid, secondary or riparian forests. These are H parmata (Ethiopia and Kenya, Central and West Africa, to Angola), H aciculifer (Ethiopia to Cameroon and Zimbabwe, introduced into South Africa), H rugosa (southern Sudan and Uganda to Ghana and Senegal), and H silacea (Zululand and eastern South Africa).

Last full review/revision July 2011 by Michael L. Levin, PhD

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