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Ornithodoros spp


Most of the 37 Ornithodoros spp inhabit protected niches in burrows, caves, dens, cliffsides, and bird colonies. Among the few that parasitize livestock, O savignyi and O coriaceus are exceptional, because they have eyes and because they rest just below or above ground level under the shade of trees and rocks where livestock and game animals rest and sleep. O savignyi, the sand tampan, lives in semiarid areas from Namibia to India and Sri Lanka and is often tremendously abundant. It can cause fatal tick paralysis in calves. People and tethered livestock suffer severe irritation, allergy, and toxicosis from sand tampan bites, and paralysis and death of animals are recorded. O coriaceus, the “pajaroello” of hillside scrub oak habitats from northern California and Nevada to Chiapias, Mexico, occupies deer beds under trees and near large rocks. It is well known for irritating deer and cattle, and in people, its bite causes a severe skin reaction. Epizootic bovine abortion, caused by an unnamed bacterium in the order Myxococcales, is transmitted by O coriaceus. O gurneyi shelters in tree-shaded soil in arid zones of Australia where kangaroos and people rest; livestock are rare or absent in these habitats.

Among the numerous Ornithodoros spp that inhabit burrows, several species are either naturally infected with African swine fever (ASF) virus in Africa or have the laboratory-confirmed ability to harbor and transmit the agent in Europe and the Americas. The natural reservoir and vector of ASF virus is O porcinus, which is abundant in burrows of tropical African pigs and also of antbears and porcupines. It has secondarily adapted to human dwellings and domestic animal shelters, where it lives in the cracks of walls and floors. Domestic pig populations in the vicinity of infected wild pigs can be decimated by ASF. Wild and domestic pigs are not involved in the epidemiology of Borrelia duttoni, the agent of human African relapsing fever, which is transmitted by O moubata. ASF virus has been transported in infected meat to Spain where O marocanus, an inhabitant of rodent burrows and pig sties, is an efficient vector. O marocanus is also a reservoir and vector of Borrelia hispanica, the agent of Spanish-northwest African human relapsing fever. ASF has likewise been introduced in Brazil, Haiti, the Dominican Republic, and Cuba. The American O turicata, O dugesi, and O coriaceus are potential vectors of ASF virus.

O tholozani (O papillipes, also O crossi) infests burrows, caves, stables, stone and clay fences, and human habitations in semidesert, steppe, and long dry-season environments from China, southern former USSR, northwestern India, and Afghanistan to Greece, northeastern Libya, and eastern Mediterranean islands. Numerous rodents, hedgehogs, porcupines, and domestic animals support O tholozani populations. People develop severe, sometimes fatal, Persian relapsing fever when bitten by O tholozani infected with Borrelia persica.

O lahorensis, originally a parasite of wild sheep resting in the lee of cliffsides, is an important pest of stabled livestock in lowlands and mountains of Tibet, Kashmir, and southern former USSR to Saudi Arabia and Turkey, Greece, Bulgaria, and Yugoslavia. The two-host life cycle and long wintertime attachment of O lahorensis is biologically remarkable. It is deleterious to livestock held for much of the winter in heavily infested stables; it may cause paralysis, anemia, and toxicosis, and it transmits the agents of piroplasmosis, brucellosis, Q fever, tularemia, and possibly Borrelia persica, the agent of Persian relapsing fever.

O turicata parasitizes rodents that live in burrows, crevices, or caves; owls; snakes; tortoises; and also domestic pigs and other livestock in southern USA and Mexico. Contrary to most Ornithodoros feeding patterns, immature O turicata engorge in <30 min, but adults may attach for as long as 2 days. O turicata has been associated with diseases of pigs, and serious toxic reactions and secondary infections can result when people are bitten.

O furucosus parasitizes people and livestock in houses and stables in northwestern South America. Other South American pests of livestock and people, probably originally parasites of the peccary, are O braziliensis and O rostratus.

Last full review/revision May 2015 by Michael L. Levin, PhD

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