Omsk hemorrhagic fever

Omsk hemorrhagic fever is a viral hemorrhagic fever caused by a Flavivirus.

It is found in Siberia. It is named for an outbreak in Omsk.

Etiology

Omsk Hemorrhagic Fever is caused by the Omsk Hemorrhagic Fever Virus (OHFV), a member of the Flavivirus family. The virus was discovered by Mikhail Chumakov and his colleagues between 1945 and 1947 in Omsk, Russia. The infection is found in western Siberia, in places including Omsk, Novosibirsk, Kurgan, and Tyumen. The virus survives in water and is transferred to humans via contaminated water or an infected tick.

Evolution

The virus appears to have evolved within the last 1000 years. The viral genomes can be divided into 2 clades—A and B. Clade A has five genotypes and clade B has one. These clades separated about 700 years ago. This separation appears to have occurred in the Kurgan province. Clade A subsequently underwent division into clade C, D and E 230 years ago. Clade C and E appear to have originated in the Novosibirsk and Omsk Provinces respectively. The muskrat Ondatra zibethicus which is highly susceptible to this virus was introduced into this area in the 1930s.

Viral hemorrhagic fever

The viral hemorrhagic (or haemorrhagic) fevers (VHFs) are a diverse group of animal and human illnesses in which fever and hemorrhage are caused by a viral infection. VHFs may be caused by five distinct families of RNA viruses: the families Arenaviridae, Filoviridae, Bunyaviridae, Flaviviridae, and Rhabdoviridae. All types of VHF are characterized by fever and bleeding disorders and all can progress to high fever, shock and death in many cases. Some of the VHF agents cause relatively mild illnesses, such as the Scandinavian nephropathia epidemica (a Hantavirus), while others, such as Ebola virus, can cause severe, life-threatening disease.

Signs and symptoms

Signs and symptoms of VHFs include (by definition) fever and increased susceptibility to bleeding (bleeding diathesis). Manifestations of VHF often also include flushing of the face and chest, small red or purple spots (petechiae), bleeding, swelling caused by edema, low blood pressure (hypotension), and shock. Malaise, muscle pain, headache, vomiting, and diarrhea occur frequently. The severity of symptoms varies with the type of virus. The “VHF syndrome” (capillary leak, bleeding diathesis, and circulatory compromise leading to shock) appears in a majority of people with filovirus hemorrhagic fevers (e.g., Ebola and Marburg virus), Crimean–Congo hemorrhagic fever (CCHF), and the South American hemorrhagic fevers caused by arenaviruses, but only in a small minority of patients with dengue, Rift Valley fever, and Lassa fever.

Omsk

Omsk (Russian: Омск; IPA: [omsk]) is a city and the administrative center of Omsk Oblast, Russia, located in southwestern Siberia 2,236 kilometers (1,389 mi) from Moscow. With a population of 1,154,116, it is Russia's second-largest city east of the Ural Mountains after Novosibirsk, and seventh by size nationally.

During the Imperial era, Omsk was the seat of the Governor General of Western Siberia, and later of the Governor General of the Steppes. For a brief period during the Russian Civil War in 1918–1920, it served as the capital of the anti-Bolshevik Russian State and held the imperial gold reserves.

Omsk is the administrative center of the Siberian Cossack Host. It also serves as the see of the bishop of Omsk and Tara, as well as the administrative seat of the Imam of Siberia.

Geography

Omsk stretches along the banks of the north-flowing Irtysh at its confluence with the smaller Om River. The city has an elevation of 87 meters (285 ft) above mean sea level at its highest point.

Omsk is an important railroad hub, and is the junction point for the northern and southern branches of the Trans-Siberian Railway. The city also serves as a major hub for the regional highway network. River-port facilities handle both passengers and freight, giving the city access to navigating the extensive waterways of the Irtysh and Ob River. The waterways connect Omsk with the coal and mineral-mining towns further up the river in Kazakhstan, as well as with the oil, natural gas and lumber operations of northern Siberia. Omsk is served by the Tsentralny Airport, which offers access to domestic and international (primarily, German and Kazakh) destinations, making the city an important aviation hub for Siberia and the Russian Far East.

3406 Omsk

3406 Omsk is a main-belt asteroid discovered on February 21, 1969 by the Russian astronomer Bella Burnasheva at the Crimean Astrophysical Observatory, and given a preliminary designation of 1969 DA. It was named for the discoverer's birthplace of Omsk, the administrative center of the Omsk Oblast in Russia.

Photometric observations of this asteroid made in 2007 at the Mt. Tarana Observatory in Bathurst, Australia were used to produce a light curve that showed a period of 7.275 ± 0.006 hours with a brightness variation of 0.28 in magnitude. This indicates a ratio of 1.3 between the lengths of the major and minor axes.

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