Investigations on the structure and morphogenesis of some arboviruses isolated in the U.S.S.R.

The morphology and some stages of morphogenesis in suckling mouse brains of hitherto serologically unclassified viruses Kaspiy (LEIV-A-63), Zavashan (LEIV-Ap-6158), Artashat (LEIV-A-2366), and Paramushir (LEIV-C-2268), isolated in the U.S.S.R., of GM-710 virus isolated in Scotland, and of Sokuluk (LEIV-K-400) virus belonging to the genus Flavivirus (family Togaviridae) were studied. Virion sizes were determined and changes in infected cells described. Based on their structure and morphogenesis, the viruses Kaspiy, Artashat, Zavashan and Paramushir were referred to the family Bunyaviridae and GM-710 virus was referred to the genus Orbivirus (family Reoviridae).

Biological profile of a virus belonging to California encephalitis complex isolated in Karelian Autonomous Soviet Socialist Republic.

We investigated in white mice and in Syrian hamsters the pathogenesis of infection with a virus belonging to the California encephalitis complex isolated in the Karelian Autonomous Soviet Socialist Republic. The pathogenic properties of the virus were investigated also in green monkeys. The localization and character of lesions in the organs of given animals appeared to be similar. The virus appeared to possess neurotropic activity, it propagated in the animal body by haematogenous route. The virus was found to be heat-resistant and pH-sensitive.

Razdan virus, a new ungrouped bunyavirus isolated from Dermacentor marginatus ticks in Armenia.

A virus, designated Razdan, was isolated from Dermacentor marginatus ticks in the Armenian S.S.R. in 1973. The complement fixation tests revealed no antigenic relationships to 74 tick-borne arboviruses. The size of the virus is about 100 nm; it agglutinates goose erythrocytes at pH 5.5--7.0, is pathogenic for newborn, 14-day-old and adult white mice and multiplies in primary and continuous cell cultures. Morphological properties of the virus permit its classification as a member of the family Bunyaviridae.

Experimental study of the reproduction of Karshi virus (Togaviridae, flavivirus) in some species of mosquitoes and ticks.

The strain Kaz-816 of Karshi virus was isolated in 1976 from H. asiaticum ticks collected in the North of Central Asia (Alma-Ata region of the Kazakh Soviet Socialist Republic). Both ticks and mosquitoes can be vectors of Karshi virus as proved experimentally by reproduction of the virus in Hyalomma asiaticum and Dermacentor daghestanicus ticks and Culex pipiens molestus, Anopheles atroparvus an Aedes aegypti mosquitoes as well as by transmission to newborn mice by the bite of infected mosquitoes.

Sikhote-Alin virus, a new member of the cardiovirus group (Picornaviridae) isolated from Ixodes persulcatus ticks in Primorie Region.

A virus, designated Sikhote-Alin, was isolated in 1970 from Ixodes persulcatus ticks collected from a wild boar in the Primorie region (U.S.S.R.) Sikhote-Alin virus showed no haemagglutinating activity and no antigenic relationships with arboviruses of 12 antigenic groups, 17 ungrouped tick-borne arboviruses, porcine enteroviruses and coxsackie A (types 1-18) viruses. An one-way antigenic relationship was demonstrated by complement fixation with cardioviruses (Mengo and Columbia-SK strains). The virus contains RNA, is resistant to lipid solvents, highly thermostable in the presence of 1 M MgCl2 and its size is over 20 nm but less than 25 nm. All these properties make it possible to consider it as a new member of the cardiovirus group (genus Enterovirus; Picornaviridae).

Khasan virus, a new ungrouped bunyavirus isolated from Haemaphysalis longicornis ticks in the Primorie region.

Strain LEIV-776P, possessing no haemagglutinating activity was isolated in 1971 in the Primorie region (U.S.S.R.) from Haemaphysalis longicornis Neumann 1091 tick. Complement fixation (CF) tests revealed no antigenic relationship with 24 antigenic groups of arboviruses or 21 ungrouped viruses isolated from ticks. The virus isolate contains RNA and is relatively sensitive to ether and sodium deoxycholate; it is pathogenic for suckling mice and two-week-old white mice by the intracerebral route, and replicates in primary cultures of chick and duck fibroblasts and green monkey kidneys and in a continuous line of pig embryo kidney cells without any cytopathic effect. According to electron microscopy, its size is 90-110 nm. Its morphological properties permit to classify it as a member of the family Bunyaviridae.

[Specific markers for the detection of circulation of Tahyna, Inko and Batai viruses (Bunyaviridae, Bunyavirus) in humans, mosquitoes, ticks and cattle of the Ul'ianovsk region]. / Spetsificheskie markery tsirkuliatsii virusov Taginia, Inko i Batai (Bunyaviridae, Bunyavirus) sredi naseleniia, komarov, kleshchei i krupnogo rogatogo skota Ul'ianovskoi oblasti.

Comprehensive examinations of the population, sanguivorous arthropoda and domestic animals were for the first time held in the territory of the Ulyanovsk region. An active circulation of certain arboviruses was detected and a predominantly ecological relation of California encephalitis serogroup viruses with Aedes mosquitoes, on the one hand, and of Batai viruses with Anopheles mosquitoes, on the other hand, was established. The most reliable detection of antibodies to California encephalitis viral complex was pointed out.

[Isolation of viruses of antigenic complexes of California encephalitis and Bunyamwera (Bunyaviridae, Bunuavirus) from mosquitoes in northeast Asia]. / Izoliatsiia virusov antigennykh kompleksov Kaliforniiskogo éntsefalita i bun'iamvera (Bunyaviridae, Bunuavirus) iz komarov na severo-vostoke aziatskogo kontinenta.

Studies in suckling mice and by direct solid-phase enzyme immunoassay were carried out with 111,1 thousand Aedes mosquitoes collected in July, 1986, in tundra, forest-tundra, and northern taiga of Kamchatka region and Chukotka autonomous district of Magadan region (North-Pacific natural area within 69 degrees-53 degrees North and 156 degrees-177 degrees East). Eleven strains were isolated of which 7 were classified as members of the California encephalitis complex (Tahyna-like strains) and 4 as members of the Bunyamwera complex (Batai-like strains). According to electron-microscopic studies of 2 strains (one from each antigenic complex), both were classified as belonging to the family of Bunyaviridae. Strains of both complexes were isolated in all landscape zones examined--tundra, forest-tundra, northern taiga. Virus-neutralizing antibodies to them were found in human and reindeer sera also in all the landscape zones, to Tahyna virus in 11%-61%, to Batain virus in 2%-6% blood specimens. No antibody to Uukuniemi virus was found.

[Sakhalin antigenic group (Bunyaviridae family)]. / Antigennaia gruppa Sakhalin (semeistvo Bunyaviridae).

Serological study of viruses belonging to the Sakhalin group showed Paramushir virus isolated in the USSR and Avalon virus isolated in Canada to be identical in all the tests used. The data on the cultural properties of the Sakhalin group viruses, the virions buoyant densities in sucrose gradient, the data on thermal sensitivity and UV inactivation of the viruses, on their morphology and morphogenesis are presented.

[Chim virus, a new arbovirus isolated from ixodid and argasid ticks collected in the burrows of great gerbils on the territory of the Uzbek SSR]. / Virus Chim--novyi arbovirus, vydelennyi iz iksodovykh i argasovykh kleshchei, sobrannykh v norakh bol'shikh peschanok na territorii Uzbekskoi SSR.

Five strains of hitherto unknown arbovirus designated Chim by the place of primary collection of ticks was isolated from Ixodid and Argasid ticks collected in the Uzbek SSR in burrows of great gerbils. The virus has no antigenic relationships with arboviruses previously isolated from ticks, its size varies from 100 to 220 nm, it contains RNA and has a lipid-containing envelope. Chim virus is pathogenic only for suckling mice by the intracerebral route and exerts cytopathic effect in continuous L, Rh, BHK cell lines.

[Kyzylagach virus (family Togaviridae, genus alphaviruses), a new arbovirus isolated from Culex modestus mosquitoes trapped in the Azerbaijani SSR]. / Virus Kyzylagach (semeistvo togaviride, rod al'favirusov)--novyi arboviruses), izolirovannyi iz komarov Culex modestus, otlovlennykh v Azerbaidzhanskoi SSR.

A strain of LEIV 65A virus was isolated in 1969 from Culex modestus mosquitoes collected in the Kyzylagach preserve, the Azerbaijan SSR, in a colony of Ciconiiformes birds. Investigations of the antigenic properties of this virus by the complement fixation and neutralization tests as well as by electron microscopy showed it to belong to alphaviruses of the Togaviridae family. Kyzylagach virus had one-way relations with Sindbis virus. Some biological and biophysical-biochemical properties of the virus were studied.

[Isolation of the Tahyña bunyavirus in the Arctic]. / Izoliatsiia bun'iavirusa Tiaginia v Zapoliar'e.

Tahyna virus (Bunyaviridae, Bunyavirus, the California encephalitis complex) was isolated from Aedes communis complex mosquitoes collected at the border of the north-taiga landscape zone (in latitude 68 degrees North and longitude 33 degrees East) at the Kolsky peninsula (the Murmansk region). The LEIV-9843 Mur strain was isolated from 2.4 thousand mosquitoes collected there (altogether 3.8 thousand mosquitoes had been collected in the Murmansk region). This is the first isolation in the USSR of a California complex virus in the Arctic and the northernmost site of Tahyna virus isolation in the world. 18% of the human population residing near the site of the virus isolation had virus-neutralizing antibody to Tahyna virus.

[Isolation of the causative agent of Karelian fever from Aedes sp. mosquitoes]. / Izoliatsiia vozbuditelia Karel'skoi likhoradki ot komarov Aedes sp.

The results of isolation of an Alphavirus strain from Aedes sp. mosquitoes collected in the focus of Karelian fever are presented. According to the results of serological studies, the isolated strain LEIV-9298 Karelia belongs to the antigenic complex Sindbis-Western equine encephalomyelitis. The appurtenance of the isolated agent to the Alphavirus genus has been confirmed by electron microscopic examinations. A rise of antibody titres to LEIV-9298 Karelia virus in paired sera of subjects with a history of Karelian fever allows it to be considered the causative agent of this disease.

[Isolation of Tamdy virus (Bunyaviridae) pathogenic for man from natural sources in Central Asia, Kazakhstan and Transcaucasia]. / Izoliatsiia patogennogo dlia cheloveka virusa Tamdy (Bunyaviridae) iz prirodnykh istochnikov v Srednei Azii, Kazakhstane i Zakavkaz'e.

Isolation of 47 strains of Tamdy virus (Bunyaviridae) in the Uzbek SSR, Turkmen SSR, Armenian SSR, Kazakh SSR, and Kirghiz SSR was analysed. Thirty-two strains were isolated from Hyalomma asiaticum ticks in which transovarial transmission of the virus was demonstrated. Three subspecies of H. asiaticum are associated with semi-desert and desert landscapes of the Asian continent. The association of Tamdy virus with hosts of various stages of metamorphosis of the ticks, in particular, with cattle and great gerbils is discussed.

[Isolation of the virus of Syr-Darya Valley fever]. / Vydelenie virusa likhoradki doliny Syr-Dar'i.

In the course of studies on the ecological structure of acute febrile diseases in the season of activity of blood-sucking arthropods strains of a virus antigenically related to Sikhote-Alyñ virus were isolated from the blood of a patient and from Ixodid ticks. This paper presents the results of the study on the causative agent and the clinical picture of the disease caused by this virus. The virus was found to be a new one for science; its appurtenance to the family Picornaviridae, genus Cardiovirus, the antigenic group of encephalomyocarditis has been determined. The virus has been designated "Syr-Darya Valley fever virus" by the area of its isolation.

[Preparation of rat ascitic fluids immune to the Sakhalin group viruses (fam. Bunyaviridae)]. / Poluchenie immunnykh astsiticheskikh zhidkostei krys k virusam gruppi Sakahlin (Sem. Bun'iaviride).

A method for preparation of rat immune ascitic fluids (IAF) to arboviruses of the Sakhalin group (the family Bunyaviridae) is described. These IAFs were 2-8-fold more active in the CFT and AGDP tests than similar preparations produced in white mice. Besides, this method is more economic.

[Etiology of Karelia fever--a new arbovirus infection]. / Etiologiia karel'skoi likhoradki--novoi arbovirusnoi infektsii.

In August-September 1981, in some areas of Karelia (on the border of northern and middle taiga) there occurred diseases with signs of fever, rash, and arthralgia developing in some patients into a chronic condition. Examinations of paired sera from patients with the acute disease and from convalescents using a set of Toga- and Bunya-viruses showed the etiology of the disease to be associated with a virus from the Togaviridae family, genus Alphavirus, of the antigenic Sindbis complex.

[Pathogenic properties of the LEIV23 Astrakhan strain of Batai virus for primates]. / Patogennye svoistva dlia primatov virusa Batai, shtamm LEIV23 Astrakhan'.

Pathogenic properties of Batai virus, LEIV23 Astrakhañ strain, isolated from Aedes vexans mosquitoes in Astrakhañ region were studied comparatively. The degree of susceptibility to the virus of green monkeys and rodents (white mice, Syrian hamsters), and the pattern of lesions produced by the virus in organs of these animals were established. The virus was shown to have a comparatively wide host range affecting phylogenetically far distant animals. Monkeys were found to have virus-carrier state for 50 days (the observation period). The virus is pantropic. Apparently mammals may be virus hosts in nature, but human infection cannot be ruled out. This requires further study in an epidemiological experiment.

[The characteristics of the pathogenic properties of new strains of viruses of the California encephalitis antigenic complex isolated in Arkhangelsk Province]. / Kharakteristika patogennykh svoistv novykh shtammov virusov antigennogo kompleksa kaliforniiskogo éntsefalita, izolirovannykh v Arkhangel'skoi oblasti.

Neurotropic properties of Leiv 12724 Ax and Leiv 13004 Ax strains were demonstrated by inoculation of green monkeys, Syrian hamsters and white mice using different routes. The strain Leiv 13004 Ax showed more marked pathogenicity for monkeys and rodents producing lesions in all parts of the brain: temporal, frontal, occipital, cerebellar, medulla oblongata and spinal cord where productive vasculitis, perivascular infiltrations, hemorrhages, and dystrophy of nerve cells were observed. In hamsters, the strains Leiv 13004 Ax and Leiv 12724 Ax inoculated subcutaneously produced latent infection with long-term virus carrier state.

[A comparative analysis of the polypeptides of the the Sindbis and Karelian fever viruses]. / Sravnitel'nyi analiz polipeptidov virusov Sindbis i karel'skoi likhoradki.

In pulse-chase experiments with Karelian fever virus-infected cells, proteins were found with molecular weights of 130, 98, 78, and 62 kD of which the first, second and fourth were classified as polypeptide precursors of the structural proteins of virion. The molecular weights of proteins E1, E2 and C of 52, 47 and 34 kD, respectively, as well as isoelectric points of isolated glycoproteins (pI E1 = 6.3, pI E2 = 8.4) were similar in KFV (strain Leiv-9298) and Sindbis virus (strain AR339). The antigenic similarity of the strains under study in neutralization test with hyperimmune sera, the identity of physicochemical characteristics of the structural proteins of KFV and prototype Sindbis virus strain suggest a close relationship of the Leiv-9298 strain to the Afro-European variants of Sindbis virus.