From Big Medical Encyclopedia

TOGAVIRUSA (Togaviridae; lat. toga a raincoat + viruses) — family of viruses from the one-filamentous not segmented infectious RNA of a linear form (plus thread). Nek-rye T. is called by diseases in the person.

This. Togaviridae includes 4 sorts: Alphavirus, Flavivirus, Rubivirus and Pestivirus, and also a number of not classified viruses (viruses of arteritis of horses, lactate dehydrogenases of mice, hemorrhagic fever of monkeys and the virus causing cell fusion). In total alpha viruses (see) and the majority of viruses of the sort Flavivirus belong to to an arbovirus (see) since are transferred to vertebral owners (to rodents, birds, etc.) by mosquitoes, ixodic mites and other blood-sicking arthropod carriers.

The sort Alphavirus (a standard virus — Sindbis) combines 23 arbovirus of antigenic group A transferred by mosquitoes. The size of virion is 60 — 65 nanometers. The nucleocapsid has cubic type of symmetry, is surrounded with a lipidosoderzhashchy cover. RNA makes 6% of the weight (weight) of virion, coefficient of sedimentation of 42 — 50 S, there are 3 — 4 structural polypeptides. Assembly of virions comes in cytoplasm by budding from a plasma membrane. Viruses belong to 3 antigenic complexes: east (1 virus), western (8 viruses) and Venezuelan (14 viruses) encephalomyelitis of horses. At least 11 viruses cause diseases of the person (see. Arboviral diseases ), shown fever, arthritis, rash (viruses of Chikungunya, Mayaro, Mukambo, O'Nyong-nyong, Ross River, Sindbis) or fever and a syndrome of encephalitis, napr, viruses of the western, east and Venezuelan encephalomyelitis of horses (see Encephalomyelitis horse). Viruses of Evergleyds and the wood Semliki have veterinary value. Alpha viruses are widespread on all continents. In the USSR 4 viruses are allocated: Geta, Kyzylagach, the woods This-sided and Sindbis, and a virus Sindbis causes a disease of people.

The sort Flavivirus (Latin of flavus yellow) includes 56 viruses of antigenic group B transmitted by mosquitoes and ixodic mites and also viruses with an unspecified way of transfer. Viruses of a dengue (see), yellow fever (see), diseases of the Kyasanursky wood are a part of a sort (see. Kyasanursky wood disease ), the Omsk hemorrhagic fever (see), a tick-borne encephalitis (see a tick-borne Encephalitis), encephalitis of the valley of Murray, or the Australian encephalitis, the Japanese encephalitis (see Encephalitis mosquito), etc. The size of virion of 48 — 55 nanometers, RNA makes 8% of weight of virion, coefficient of sedimentation of 40 — 45 S, there are 3 structural polypeptides. Assembly of virion is associated with a cytoplasmic membrane. At least 26 viruses cause the diseases of the person which are characterized by fever (viruses of Banzi, Bussukuara, Ilheus, Zeke, Qarshi, Kundzhin, Sepik, Spondveni, Seal), fever with rash and polyarthritis (viruses of a dengue 1 — 4, the Western Neil), fever with a hemorrhagic syndrome (viruses of a dengue 1 — 4, diseases of the Kyasanursky wood, the Omsk hemorrhagic fever, yellow fever), the phenomena of encephalitis (viruses of Apoi, Ilheus, Langat, Ne-gishp, encephalitis of the valley of Murray, a tick-borne encephalitis, Rosio, encephalitis St. Louis and the Japanese encephalitis, Rio Bravo, Povassan, the Scottish encephalomyelitis of sheep). These viruses are widespread on all continents. In the USSR the Western Neil's viruses, tick-borne and Japanese encephalitis, Qarshi, the Omsk hemorrhagic fever, Negisha, Povassan, Sokuluk, Seal are endemic; from them only for a virus Sokuluk yet not a setpoint value in pathology of the person.

The sort Rubivirus (Latin of ruber red) is presented only by a virus rubellas (see). Size of virion 58 + 7 nanometers. Coefficient of sedimentation of RNA 40 S. The virus has 3 structural polypeptides. Unlike other T. contains a neuraminidase. The virus is replicated in many cellular cultures, but has a cytopathic effect only on VNK — 21, VERO, SIGR and primary cultures of cells of a fruit of the person after adaptation. The indicator of replication is the interference with any pathogenic virus. For se-rol. researches use reactions of radial hemolysis and a delay of hemolysis. Children of younger school age, and also teenagers and young people have a rubella preferential. It is dangerous to pregnant women in connection with teratogenic action of a virus. Malformations of a fruit (blindness, deafness, underdevelopment of extremities, etc.) arise at infection on the 1, 2, 3 and 4 month of pregnancy respectively in 33, 25, 9 and 4% of cases. Therefore the disease of a rubella serves as the direct indication to its interruption in the 1st trimester of pregnancy. Apply the live vaccine used out of the period of pregnancy to prevention.

The sort Pestivirus (Latin of pestis plague) includes viruses of diarrhea of cows, the European plague of pigs and antigenically related to them the virus affecting sheep. The size of virion is 40 — 60 nanometers. Coefficient of sedimentation of RNA of 38 — 45 S. There are 3 — 4 structural polypeptides. Viruses cause a heavy epizooty among page - x. animals, bringing extensive economic damage.

See also Viruses .

Bibliography: Lviv D. K. and Ilyichev V. D. Migrations of birds and transfer of contagiums, page 3 7, M., 19 79; L in about in D. K. and L e e d e in A. D. Ekologiya of an arbovirus, M., 1974; The General and private virology, under the editorship of V. M. Zhdanov and S. Ya. Gaydamovich, t. 2, page 49, M., 1982; Porterfield J. S. and. lake of Toga-viridae, Intervirology, v. 9, p. 129, 1978; Togaviruses, biology, structure, replication, ed. by R. W. Schlesinger, N. Y. and. o., 1980.

D. K. Lvov.