[Actual problems of hemorrhagic fever with renal syndrome].

From 2000 to 2011 85 600 cases of hemorrhagic fever with renal syndrome (HFRS) were registered in Russian Federation. Epidemically active foci of HFRS infection are located generally in temperate latitudes of the European part and the Far East. In the Far East regions whose fraction of all the HFRS disease cases in Russia is around 2%, the causative agents of the infection are Hantaan, Amur, Seoul hantaviruses, the natural reservoir for those are striped field mouse, Korean field mouse and brown rat. In the European part of Russia the causative agent of the infection are Puumala hantavirus as well as 2 genetic subtypes of Dobrava virus, the main reservoirs of those in the nature are bank vole, striped field mouse and Black Sea field mouse, respectively. 9 strain of Puumala and 10 strains of Dobrava virus were isolated. Based on sequencing of Dobrava virus strains significant differences were detected between Dobrava virus strains isolated from Black Sea field mouse from Sochi and striped field mouse from Lipetsk Region. Cultural inactivated vaccine against HFRS was developed and completed preclinical trials.

[Dynamics of hantavirus detection in the excretory organs of Apodemus mice and its relation to epidemic manifestations of hantavirus infection].

This paper presents data on the detection of hantavirus in the excretory organs of Apodemus mice which are natural carriers of pathogenic hantaviral serotypes in the Primorye Region. Acute infection periods were detected in naturally infected rodents with the highest hantavirus dissemination to the environment in different phases of rodent population cycles. There was a relationship between the rise of morbidity and the seasonal manifestation of hemorrhagic fever with renal syndrome morbidity and activity of hantavirus reproduction in the murine excretory organs.

[Inhibiting effects of fucoidans on Hantaan virus adsorption on a model of peritoneal macrophages in vitro].

A model of peritoneal macrophages was used to study the effect of fucoidans from brown seaweeds on the adsorption of Hantaan virus. Fucoidans were found to have antiviral activity, but to differ in the inhibition of hantavirus adsorption, which was associated with their structural features. The mechanism of their action is assumed to be shown via ligand-receptor interaction with certain cell membrane receptors and via blockage of hantavirus glycoproteins (G1 and G2), resulting in adsorption inhibition and preventing viral penetration into the macrophages.

[Time course of changes in antibodies of various avidity in murine rodents in the epizootic and epidemic processes in hantavirus infection].

The paper presents the results of studying the time course of changes in antibodies of varying avidity in murine rodents. The presence of low-avidity antibodies is shown to reflect the status of acute infection in the rodent population and their active viral shedding. A relationship is shown between the detection of low-avidity antibodies in animals in spring and autumn and the rise of endemic hemorrhagic fever (EHF) morbidity. The findings demonstrate it possible to use data on the determination of antibodies of varying avidity in the population of murine rodents for the assessment of epizootic and epidemic processes.

[Screening of biopolymers from sea hydrocoles affecting the adsorption of Hantaan virus].

The biopolymers extracted from sea hydrocoles were screened and a group of sulfated polysaccharides--fucoidans having a pronounced inhibitory effect on the adsorption of Hantaan virus in the cultured Vero E6 cells was identified. The mechanism of action of sulfated polysaccharides was realized through competitive carbohydrate-specific binding to cell membrane receptors and through ligand-receptor interaction and blocking of Hantaan virus glycoproteins (G1 and G2).

Metabolic activity of macrophages infected with hantavirus, an agent of hemorrhagic fever with renal syndrome.

Monocytes/macrophages are thought to play an important role in pathogenesis of viral infections. These cells are involved in distribution and persistence of viruses in the organism and also influence the regulation of immune reactions. The functional and enzymatic activities of macrophages infected with an agent of hemorrhagic fever with renal syndrome were analyzed for the first time. This disease is caused by a virus of the Hantavirus genus, the Bunyaviridae family. Activities of ectoenzymes 5 -nucleotidase and ATPase of the plasma membrane of the hantavirus-infected macrophages decreased along with the antigen accumulation in the infected cells. The contact of phagocytes with hantavirus resulted in activation in the cells of the oxygen-dependent metabolism and NO-synthase. The NO-synthase-dependent system of the infected macrophages was activated earlier than their oxygen-dependent system. The intracellular contents of acid and alkaline phosphatases increased within the first hours after the infection. The bactericidal activity of the hantavirus-infected macrophages relatively to Staphylococcus aureus increased during the specific antigen accumulation in the phagocytes. Thus, the infection of macrophages with hantavirus was associated with intracellular metabolic changes.

[Hemorrhagic fever with renal syndrome among servicemen in Primorskii Region of Russia].

The data about the incidence of hemorrhagic fever with renal syndrome (HFRS) among the servicemen stationed in HFRS endemic territories at Primorye Region are presented. The authors have shown the epidemiological significance of outbreaks, group and sporadic cases of HFRS especially in servicemen aged 18-20. During the outbreaks the maximal HFRS incidence is registered during 2 weeks after the first case. 104 HFRS cases were registered in the servicemen. Among them 77.8 +/- 3.0% were at the age of 18-20; 7.4 +/- 2.9% of these cases were lethal.

[A new genetic variant of the PUUV virus from the Maritime Territory and its natural carrier red-grey vole Clethrionomys rufocanus]. / Novyi geneticheskii variant virusa Puumala v Primor'e i ego prirodnyi nositel' krasno-seraia polevka Clethrionomys rufocanus.

Pulmonary tissues of red-grey voles, Clethrionomys rufocanus from Shkotovo District and Maritime Territory were investigated. rt-PCR was used to detect the hantavirus nt-222 M-segment genome and nt-403 mitochondrial DNA fragment. A new genetic variant of the PUUV virus named as "Shkotovo", that is different from other PUUV strains by 18-23%, was shown to be circulating in red-grey voles. A phylogenetic analysis denoted 2 PUUV subgroups with their rodent-host branching into C. graleolus and C. rufocanus.

[Antigenic and genetic properties of Seoul virus strains--a causative agent of hemorrhagic fever with renal syndrome]. / Antigennaia i geneticheskaia kharakteristika shtammov virusa Seul--vozbuditelia gemorragicheskoi likhoradki s pochechnym sindromom.

Data on the circulation of a new genetic variant of Seol virus, which was designated as "Vladivostok" (the name of the place where it was isolated)--VDV, were obtained, by using the antigenic and genetic analysis of hantavirus strains isolated from patients with hemorrhagic fever with renal syndrome (HFRS) and from brown rats, and described in the present paper. A complete identity of nucleotide sequences of the M-segment fragment of isolates obtained from HFRS patients and of those obtained from rats was demonstrated, which confirms the key role of brown rat as a source of infection.

[Mechanism of viral infection of macrophages by an agent of hemorrhagic fever with renal syndrome: ultrastructural aspects]. / Mekhanizm infitsirovaniia makrofagov vozbuditelem gemorragicheskoi likhoradki s pochechnym sindromom: ul'trastrukturnye aspekty.

Monocytes/macrophages are one of the first cells subjected to the infectious effect of viruses. The present paper analyses for the first time the ultrastructural changes in macrophages caused by an agent of hemorrhagic fever with renal syndrome (HERS)--hantavirus (HV). After a local fusion with the host cell plasmalemma and its adsorption on the cell surface, the HV penetrates through the macrophage membrane. This process occurred without destruction of cell plasmalemma. HV viral particles were observe within the macrophage cytoplasm mostly on the smooth granular endoplasmic reticulum vesicles. Viroplasts were defined in macrophages after a 2 h incubation, with synthesis of viral nucleoproteins and primary covers being observed on the surface of viroplasts. Viral particles left macrophages in the process of budding on the phagocyte surface. Thereby HV, similar to other enveloped viruses, realizes entrance and egress from the target cell without damaging its plasmalemma. This accounts for the viral ability to reproduce in macrophages for a long time without any cytopathological effect. Consequently, in the absence of obvious destruction changes, mononuclear phagocytes can serve as a long-term storage of viruses, and thus being involved in HV dissemination during HERS.

[Use of kinetic hemagglutination inhibition test in study of antigenic relationships of hantavirus strains circulating in foci of hemorrhagic fever with renal syndrome in Southern Far East of Russia]. / Ispol'zovanie kinetichesko'i reaktsii tormozheniia gemaggliutinatsii dlia izucheniia antigennykh vzaimosviaze'i shtammov khantavirusov, tsirkuliruiushchikh v ochagakh gemorragichesko'i likhoradki s pochechnymsindromom iuga Dal'nego Vostoka Rossii.

The kinetics of reaction between hemagglutinating antigens and immune sera to 10 hantavirus strains (7 isolated in the Primorye territory and 3 in other regions) was studied in the cross kinetic hemagglutination inhibition (KHAI) test. An A parameter is suggested for evaluation of the similarity and differences between the studied strains. This parameter helped detect antigenic differences between Hantaan and Seoul viruses and the inter-type differences between Hantaan-like strains. KHAI is more specific than HAI studies of antigenic relationships between strains of different hantavirus serotypes.

Genetic diversity of hantaviruses associated with hemorrhagic fever with renal syndrome in the far east of Russia.

To identify the hantaviruses causing hemorrhagic fever with renal syndrome (HFRS) in the Far East of Russia, blood samples collected from HFRS patients in 1994-1998, were examined by reverse transcription-polymerase chain reaction. In addition, 36 sera were tested by an immunofluorescence assay for antibodies against Hantaan, Seoul, Puumala, and Khabarovsk viruses, and 54 samples were tested by plaque reduction neutralization test. With both serological assays, the highest antibody titers were to Hantaan and/or Seoul viruses. Of 110 blood samples 36 were found RT-PCR positive. Phylogenetic analysis the sequences of a 256-nucleotide (nt) fragment of the hantavirus M genome segment revealed at least 3 genetically distinct hantavirus lineages. Nucleotide sequence comparison showed that two of the lineages, designated as FE and Amur (AMR), differed from one another by 15.9-21.2% and from Hantaan virus by 9.8-17.5%. The third lineage, VDV, differed from Seoul virus by 2.6-5.1%. All S segment sequences were from FE lineage, and differed from Hantaan virus by 10.7-12.6%. Thirty of the 36 (83%) analyzed sequences were found to be the FE genotype, which is very similar to that of Hantaan virus, strain 76-118. Of the remaining hantaviruses, 11% were the AMR genotype, and 6% the VDV genotype, which are genetically novel genotypes of Hantaan or Seoul viruses, respectively.

[Circulation of Seoul hantavirus in populations of synanthropic rodents and its significance in the incidence of hemorrhagic fever with renal syndrome in the Primorye territory]. / Tsirkuliatsiia khantavirusa Seul v populiatsiikh sinantropnykh gryzunov i ego znachenie v zabolevaemosti gemorragicheskoi likhoradkoi s pochechnym sindromom v Primorskom krae.

The prevalence of Seoul virus in the Primorie territory is presented and its significance in the morbidity structure with regard to hemorrhagic fever with the renal syndrome (HLPS) is discussed. Epidemiological and clinical manifestations of HLPS caused by Seoul virus are described. The authors conclude that in the urban foci of HLPS it is associated mainly with Seoul virus, while in the rural foci, with Hantaan virus.

[Functional activity of hemagglutinins from Hantaan viruses strains and use of hemagglutinating antigens for serodiagnosis hemorrhagic fever with kidney syndrome]. / Funktsional'naia aktivnost' gemaggliutininov shtammov virusa Khantaan i ispol'zovanie gemaggliutiniruiushchikh antigenov dlia serodiagnostiki gemorrhagicheskoi likhoradki s pochechnym sindromom.

Hemagglutinins of Hantaan virus strains isolated in Southern Far East of Russia from patients with hemorrhagic fever with the renal syndrome and from rodents, natural vectors of the virus, were studied in the cross kinetic hemagglutination inhibition test with immune sera to the studied strains. The strains differed by the functional activity index. Use of hemagglutinins of functionally active Hantaan strains in serologic studies notably improves the diagnostic efficacy of the hemagglutination test in Hantavirus infection.

Genetic diversities of hantaviruses among rodents in Hokkaido, Japan and Far East Russia.

Seroepizootiologic surveys among wild rodents were carried out in Japan and Far East Russia in 1995 and 1996. Seropositive animals were only identified in Clethrionomys rufocanus (23/134) in Hokkaido, Japan. On the other hand, seropositives were identified in C. rufocanus (1/8), Apodemus agrarius (2/66), Apodemus spp. (2/26) and Microtus fortis (3/22) in Vladivostok, Far East Russia. Total RNA was isolated from lungs of seropositive animals and the S genome segments were amplified by PCR, cloned and sequenced. The S and M genomes of hantavirus, derived from Japanese C. rufocanus (Tobetsu genotype), were most closely related with Puumala viruses (76-79% nucleotide and 95% amino acid identities for S genome, 70-78% nucleotide and 87-92% amino acid identities for M genome). The recombinant nucleocapsid protein of Tobetsu genotype was antigenically quite similar with that of Sotkamo. These suggest that the virus endemic in Japanese C. rufocanus belongs to Puumala virus. Phylogenetic analysis indicates that the genotype forms a distinct lineage within Puumala viruses. Partial S segment (1-1251 nt), derived from seropositive M. fortis in Vladivostok, was sequenced and analyzed. The S genome segment, which was designated Vladivostok genotype, was most closely related with Khabarovsk virus (79% nucleotide and 90% amino acid identities) which was isolated from M. fortis.

Community structure and prevalence of hantavirus infection in rodents: a geographic division of the enzootic area in far eastern Russia.

The results of an extensive rodent trapping effort throughout the southern part of far eastern Russia and hantavirus antigen screening of tissues were used to develop a multifaceted approach for the geographic division of the enzootic territory of hantavirus. Four species of rodents (Apodemus agrarius, Apodemus peninsulae, Microtus fortis, and Clethrionomys rufocanus) comprised 88.5 percent of 10,595 captured rodents and 94.1 percent of 996 antigen-positive animals. Rodent fauna and the prevalence and distribution of hantavirus antigen-positive animals were compared among major biotic communities in the region. The species composition of the rodent communities and the predominant hantavirus reservoir species were used as criteria to define zones with similar enzootic characteristics.

[The ecological aspects of the epidemiology of hemorrhagic fever with renal syndrome in the south of the Far East in Russia]. / Ekologicheskie aspekty épidemiologii gemorragicheskoi likhoradki s pochechnym sindromom na iuge Dal'nego Vostoka Rossii.

The data on the relationship between the epizootic process in the population of mice (the source of Hantavirus infection) and the seasonal manifestations of morbidity in hemorrhagic fever with renal syndrome (HFRS) in the southern region of the Russian Far East are presented. The asynchronous course of the epizootic process in the population of rodents causes irregularity in the spread of HFRS in the region and periodicity in the appearance of foci. Seasonal rises in HFRS morbidity coincide with the activity of the epizootic process in the population of mice: spring-summer rises with an increase in the number of infected rodents in the populations of large Japanese field mice and autumn-winter rises in voles.

[Approaches to selecting a strain of hantavirus for developing an inactivated brain vaccine]. / Podkhody k vyboru shtamma virusa khantaan dlia razrabotki inaktivirovannoi mozgovoi vaktsiny.

Four strains isolated from patients with hemorrhagic fever with the renal syndrome and from field mice, natural hosts of Hantavirus, were examined in order to choose a functionally active strain fit for the development of inactivated Hantavirus brain vaccine. Virulent strain PM-10508/89 isolated from mouse lungs was chosen. The strain was highly virulent for newborn mice and rats: 100% of infected mice aged up to 24 h and 75% of rats developed an acute lethal infection upon challenge. The incubation period of Hantavirus adapted to mouse brain was decreased from 19 to 7 days. The infective titer of the virus in brain suspension was 0.1 to 6.5 lg LD50/ml. The strain was highly immunogenic and possessed a high hemagglutinating activity.

[Highly purified agar for virological, immunochemical and microbiological research]. / Vysokoochishchennyi agar dlia virusologicheskikh, immunokhimicheskikh i mikrobiologicheskikh issledovaniiakh.

A new effective method for the preparation of highly purified agar for microbiological, virological and immunochemical investigations has been obtained and the technology for its production has been developed. The study revealed that the physico-chemical characteristics of newly obtained highly purified agar are much better than those of microbiological agar currently produced in Russia and not inferior to those of the best kinds of agar produced by Difco (USA), Serva and Ferak (Germany). The method of purification is protected by an author's certificate. The production of this agar for medical purposes has been permitted. The manufacturing plant "Medbioagar", created under the auspices of the Research Institute of Epidemiology and Microbiology has now started the serial production of highly purified agar under the name "Primagar". Further increase of the production of the preparation will facilitate its introduction into laboratory practice with the use of modern research methods in the fields of microbiology and virology, molecular biology and genetics, immunology and biochemistry.