segments. It has some sequence similarities with UPOV and ABV. Upolu virus (UPOV) UPOV was first isolated on Upolu Cay in the Great Barrier Reef, Australia in 1966, from soft-bodied ticks of the species Ornithodoros capensis associated with the sooty tern (Onychoprion fuscatus). No natural vertebrate host has been identified, but the virus is highly pathogenic to mice in laboratory infections. The virion can either be spherical, with a diameter in the range 75–95 nm, or slightly ovoid, with a range of dimensions from 75 nm × 85 nm to 105 nm × 120 nm. The genome has six RNA segments. It is most similar to ABV, with some similarity to THOV and JOSV. DHOV-like viruses Dhori virus (DHOV) DHOV was first isolated from Hyalomma dromedarii hard-bodied ticks infesting camels in Gujarat, India, in 1961. It has since been observed in eastern Russia, Pakistan, Egypt, Saudi Arabia, Kenya and southern Portugal. The vector is usually a species of Hyalomma, such as H. marginatum. Where DHOV is prevalent, antibodies to the virus have been documented in camels, goats, horses, cattle and humans. The virus has been isolated from a wild hare, Lepus europaeus. DHOV can infect humans by the aerosol route after accidental laboratory exposure, causing a febrile illness and encephalitis. Under laboratory conditions it is highly pathogenic for mice, and has been proposed as a model system for highly pathogenic influenza. It has also been shown to infect birds, with the virus being isolated from a cormorant, and antibodies being observed in waterfowl. DHOV has seven RNA segments. Batken virus Batken virus was first isolated from hard-bodied ticks of the species Hyalomma plumbeum plumbeum infesting sheep near the town of Batken, Kirghizia, now in Kyrgyzstan, in 1970. It has also been found to infect mosquitoes of the species Aedes caspius Pallas and Culex hortensis Ficalbi, also in Kyrgyzstan. Its geographical range is limited to Central Asia, Transcaucasia and the area to the north of the Caspian Sea. In the laboratory it is highly pathogenic for mice, hamsters and chickens. The virion is variable in shape, with spherical and filamentous forms being observed; it has a diameter of 50–100 nm. Batken is considered a DHOV subtype; the viruses have a high degree of sequence identity (90% in the envelope glycoprotein; 96–98% in other proteins), and their antibodies crossreact. Bourbon virus Bourbon virus was identified in 2014 by next-generation sequencing of a