Vol 64, No 5 (2019)

The review contains a brief analysis of the results of investigations conducted during 40 years after smallpox eradication and directed to study genomic organization and evolution of variola virus (VARV) and development of modern diagnostics, vaccines and chemotherapies of smallpox and other zoonotic orthopoxviral infections of humans. Taking into account that smallpox vaccination in several cases had adverse side effects, WHO recommended ceasing this vaccination after 1980 in all countries of the world. The result of this decision is that the mankind lost the collective immunity not only to smallpox, but also to other zoonotic orthopoxvirus infections. The ever more frequently recorded human cases of zoonotic orthopoxvirus infections force to renew consideration of the problem of possible smallpox reemergence resulting from natural evolution of these viruses. Analysis of the available archive data on smallpox epidemics, the history of ancient civilizations, and the newest data on the evolutionary relationship of orthopoxviruses has allowed us to hypothesize that VARV could have repeatedly reemerged via evolutionary changes in a zoonotic ancestor virus and then disappeared because of insufficient population size of isolated ancient civilizations. Only the historically last smallpox pandemic continued for a long time and was contained and stopped in the 20^th century thanks to the joint efforts of medics and scientists from many countries under the aegis of WHO. Thus, there is no fundamental prohibition on potential reemergence of smallpox or a similar human disease in future in the course of natural evolution of the currently existing zoonotic orthopoxviruses. Correspondingly, it is of the utmost importance to develop and widely adopt state-of-the-art methods for efficient and rapid species-specific diagnosis of all orthopoxvirus species pathogenic for humans, VARV included. It is also most important to develop new safe methods for prevention and therapy of human orthopoxvirus infections.

Introduction. There are natural foci of Crimean-Congo hemorrhagic fever (CCHF) that vectored by Hyalomma marginatum ticks in Volga river delta (Astrakhan region, South of Russia). The circulation of Dhori virus (DHOV) (Thogotovirus: Orthomyxoviridae) has been also shown here. We hypothesized that other tick-borne arboviruses are also likely to circulate in the region. In particular, Bhanja virus (Phlebovirus: Phenuiviridae), Wad Medani virus (Orbivirus: Reoviridae), and Tamdy virus (Orthonairovirus: Nairoviridae), which were found to circulate in neighboring regions and are vectored by Haemaphysalis spp., Dermacenter spp., and Hyalomma spp. ticks.

Goals and objectives. The aim of the study was to examine ixodid ticks in Volga river delta for the presence of CCHFV, DHOV, Bhanja virus, Wad Medani virus, and Tamdy virus.

Material and methods. Ticks were collected in Volga river delta in 2017. We used molecular genetic methods for the detection and analysis of nucleic acids (PCR, sequencing, phylogenetic analysis).

Results. We detect CCHFV and DHOV RNA in H. marginatum ticks. The rate of infected H. marginatum ticks was 1.98% for CCHFV and 0.4% for DHOV. The results of genetic analysis showed that found DHOV strains are almost identical (99- 100% in the M gene) and forms a separate genetic lineage alongside of Batken virus from Central Asia. At the same time, Bhanja virus, Wad Medani virus, and Tamdy virus were not found in ticks, collected in this region.

Conclusions. DHOV is circulating in the natural foci of CCHF in the Volga river delta. The ratio of infection of H. marginatum with CCHFV and DHOV was determined for the first time.

Introduction. The complexity of the treatment of herpetic keratoconjunctivitis is due to the severity of the disease, complications, the transition to chronic relapsing forms and the insufficient effectiveness of the drugs used, which leads to a steady increase in the number of patients.

The aim of the study was to evaluate the therapeutic efficacy of the eye drug films «GlazAvir» in the experimental model of acute herpetic eye infection in rabbits.

Research objectives: to study the specific activity of «GlazAvir» and compare the long-term indicators of the level of manifestation of individual clinical signs of keratoconjunctivitis.

Material and methods. In the work we used rabbits of the Chinchilla breed, the herpes simplex virus type 1 and the eye drug films «GlazAvir». A model of ophthalmic herpetic infection was formed by infection of rabbits with virus-containing material of a pre-scarified eye cornea against the background of local anesthesia. Аnimals were treated with the drug «GlazAvir» - 1 application per day for 7 days. Animals were observed daily for 15 days, then every 3 days until the 25th day of observation. The effectiveness of the drug was evaluated at the peak of the development of the pathological process.

Results and discussion. There was a decrease in mortality from 50 to 20%, and an increase in average life expectancy by 27.87%, compared with the control in animals treated with «GlazAvir». It was noted after activation of herpetic keratoconjunctivitis on the 2nd – 5th day, at the peak of the disease (6–9th day) a statistically significant decrease in the activity of the pathological process (p<0.05) by rabbits treated with the «GlazAvir» ophthalmic drug films. The tendency to normalization by the rabbits treated with the «GlazAvir» preparation was observed until the 14th day.

Conclusion. The data obtained indicate the pronounced effectiveness of the «GlazAvir» preparation in the treatment of experimental herpesvirus keratoconjunctivitis.

To date, a lot of data on molecular genetic characteristics of different tick-borne encephalitis virus strains has appeared. Only on the basis of the E protein genome, sequences of about 1,500 TBEV strains were registered in GenBank.

The purpose of the work – revision and comparative analysis of data on complete genomes sequences of the Far Eastern subtype of TBE virus strains distributed in the Asian part of Eurasian continent.

Material and methods. The data on the complete genomes of 84 strains of TBEV isolated in Asia were used; phylogenetic analysis was performed.

Results and discussion: it was shown that variants of the TBEV of the Far Eastern subtype are circulating here and form three separate clusters (Sofjin, Senzhang- и Shkotovo-like strains). Sofjin strain (Sofjin-1953, Sofjin-Chumakov, Sofjin-KSY) was considered to be the reference for Far Eastern TBE virus subtype strains and a cluster of Sofjin-like strains. Sofjin-like strains were not found in China and Japan, but widely distributed throughout the area of Primorsky and Khabarovsk krai. The group of Senzhang-like strains was distributed in China, Eastern Siberia, Khabarovsk krai and northern Primorsky krai, but was not found in Japan (Hokkaido). According to molecular genetic characteristics the youngest and more genetically homogeneous group was the Shkotovo-like strains, isolated in the southern part of Primorsky krai, however not found on Hokkaido Island (Japan).

Conclusion: revision of the complete genome characteristics of TBEV strains revealed the features of micro-evolutionary process of viral populations in the Asian part of Eurasia, show the individual affection of strains to certain territories, as well as detect random finds of such strains in the territories of other natural foci.