Background. Hantavirus infections are one of the most important zoonotic diseases in the Russian Federation. However, the pathogenicity of Hantaviruses circulating in Siberia is still unknown. The aim of the study was to assess the incidence of Hantavirus infection in patients with fever of unknown origin from Irkutsk region and adjacent territories. Materials and methods. Serum samples collected in 2016 from individuals with symptoms of health deterioration were screened by ELISA to investigate possible Hantavirus infection, in addition to tick-borne infections. Depending on date of tick bite specific immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies to tick-borne encephalitis, borreliosis and Hantavirus were tested by ELISA or screened by PCR for tick-borne encephalitis, borreliosis, human granulocytic anaplasmosis and monocytic erlychiosis RNA/DNA. Results. Out of 92 serum samples, 6.5 % were positive for hantavirus-specific antibodies, which is at least twice higher than the seroprevalence among healthy people in the Irkutsk region. IgM and IgM+IgG antibodies were found in 5.4 % of cases, while IgG antibodies - in 1.1 % of cases. The clinical symptoms among sero-positive patients were fever, skin lesion, fatigue syndrome, headache and lymphadenitis. IgM antibodies to borreliosis were found in two hantavirus sero-positive cases. Lung tissues from small mammals captured in 2016 were screened by ELISA for the presence of Hantavirus antigen. Hantaviral antigen was detected in 6.3 % of 48 samples. Conclusions. Thus, present and previous studies demonstrate existence of natural foci of Hantavirus infections in addition to tick-born infections in the territory of the Irkutsk region.

В работе представлены результаты исследований 842 обращений в Центр диагностики и профилактики клещевых инфекций ФГБНУ НЦ ПЗСРЧ (Иркутск) людей, пострадавших от иксодовых клещей в 2014 г. Показана возможность применения метода ПЦР в реальном времени для диагностики возбудителей клещевого энцефалита, клещевого боррелиоза, моноцитарного эрлихиоза и гранулоцитарного анаплазмоза человека в крови людей или в клещах, снятых с пострадавших от ихукусов, и проведения эффективной профилактики и, тем самым, снижения инфекционной заболеваемости.

The grand-scale laboratory investigation on finding influenza type A virus in wild and synanthropic birds on vast territories of Eastern Siberia was conducted for the first time. Alongside with the ornithological investigations, we also conducted collection of over 17,000 samples of laboratory investigations of 165 bird species. In the south of Central Siberia in 2006-2011, the antibodies to antihemagglutination were found in 484 samples, 179 out of which were from synanthropic birds. During the investigation of PCR of RNA avian influenza 167 samples were isolated, 17 (10,2 %) out of which were from synanthropic species. In 2014, antibodies were isolated from 30 species, RNA avian influenza were isolated from 26 species of the following bird orders: Podicipediformes - 3/1 (in hemagglutination-inhibition reaction/polymerase chain reaction) of species, Ciconiiformes - 0/1, Anseriformes - 12/10, Gruiformes - 1/1, Charadriiformes - 7/4, Passeriformes - 6/8. In the following years the participation in epizootic process of new species/ subspecies were increased. The maximum virus carriage (40.2 %) and birds infection takes place during the period from July 15 till August 28, which is characterized mainly by the presence of a large number of multipleaged young-of-the-year water fowls on the ponds and riparian vegetation. In the process of work, there was compiled not only the list of species/subspecies of avian influenza virus carriers and vectors, but also revealed their connection with wintering areas and the main location of the recombinant subtypes of highly pathogenic virus H5N1. The cases of virus spreading and its influence on the birds of various ecologic groups were described.

During 1999-2011 we conducted the collaborative research in Northern, Central and Eastern Mongolia. Several tick-borne infections were revealed in ticks and. human patients. Most important of them are tick-borne encephalitis, Lyme disease, tick-borne rickettsiosis, human granulocytic anaplasmosis and. babesiosis. The importance, risk of infection and. spread of tick-borne diseases in Mongolia are discussed in the paper.

There are 3 subtypes of tick-borne encephalitis virus (TBEV) distinguished, at present time: European (EU), Siberian (SIB) and Far Eastern (FE). The former one is associated with Ixodes ricinus tick, whereas the latter two with I. persulcatus. The circulation of TBEV in nature is mediated by the non-viraemic transmission, between infected and. uninfected ticks co-feeding on the same hosts and. it was shown that transmission rate of «Hypr» strain (EU subtype) is much higher than rate of «Vasilchenko» strain (SIB subtype) 60 and 5 % respectively. To reveal the viral determinants of transmission efficacy, we constructed the series of recombinant viruses with gradually exchanged genes coding structural (str) and. non-structural (ns) viral proteins. The recombinant virus Hypr[str]Vs[ns] achieved the rate of non-viraemic transmission of 70 %. The introduction of separate structural genes of Hypr into Vs infectious clone has enhanced the transmission efficacy as well, though not to such extent as entire structural region but up to 33 % only. Thus, it was shown that efficacy of non-viraemic transmission of TBEV depends from properties of viral structural proteins mainly.

For the first time the results of the study of 1399 blood serum, samples from people bitten by Ixodid ticks in Predbaykalye region (East Siberia, Russia) and asking for medical care in the Center for prophylaxis of tick-borne diseases of Scientific Center of Family Health. Problems and. Human Reproduction. SB RAMS. The study showed, high, (up to 99,93 %) efficacy of early antibiotic course in preventing the Lyme disease in bitten people

The California encephalitis serogroup virus, Batai virus and Geta virus were isolated as result of investigation of distribution of arboviruses in Pribaikalye. The results of the study of influenza A virus in birds in Pribaikalye are presented as well.

The serum samples from children who reside in Tofalaria were studied for presence of antibodies against four tick-borne infections, including tick-borne encephalitis virus (TBEV), Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Ehrlichia muris and E. chaffensis. In total, 16 % of samples contained IgG antibodies against TBEV. Of them, one child (11,1 %) belonged to Tofalar nationality, two children (15,4 %) were half-breed and four (18,2 %) belonged to Russian nationality. In group of children with positive serum samples one Russian boy had antibodies to TBEV and B. burgdorferi sensu lato simultaneously. The titers were 1:1900 and 1:100 correspondently. Obtained results testify the need for development of prophylaxis of tick-borne infections.