Rabies Viruses Circulation in Western Siberia
Molecular-Epidemiological Study Isolates of Lyssavirus, Circulating in the South of Western Siberia
Tech Area / Field
- MED-DIS/Disease Surveillance/Medicine
- BIO-CGM/Cytology, Genetics and Molecular Biology/Biotechnology
3 Approved without Funding
State Research Center of Virology and Biotechnology VECTOR, Russia, Novosibirsk reg., Koltsovo
- State University of New York / Downstate Medical Center, USA, NY, Brooklyn\nCenters for Disease Control and Prevention (CDC), USA, GA, Atlanta
Project summaryThe basic purpose of the project entitled "MOLECULAR-EPIDEMIOLOGICAL STUDY OF ISOLATES OF LYSSAVIRUS, CIRCULATING IN THE SOUTH OF WESTERN SIBERIA" is to determine the natural centers of circulation of lyssavirus in the south of Western Siberia and to perform molecular-biological analysis of the revealed variants, in connection with emergent new foci of lyssavirus infection.
The neurotropic nature of Lyssaviruses, the practically universal spread and wide range of animals they infect, including humans, as well as emergence of new variants of Lyssaviruses requires us to pay serious attention to them. All of these viruses cause fatal forms of encephalomyelitis, while currently available rabies vaccines can provide protection only against two (1, 6) of 7 genotypes of the Lyssavirus genus (Perrin P, 1999; Mackenzie J.S. 2001; Favoretto SR, 2001). Rabies virus is the most dangerous representative of this genus. This virus ecology has not been properly investigated both in wild populations and natural ecosystems of the world. Outbreaks of diseases caused by different Lyssaviruses and re-emerging in different regions of the world presents serious danger for man. Lethality of rabies virus infection reaches 100% (Bowen-Davis J., 2000; East M.L., 2001).
In the territory of Western Siberia as well as all of Russia, with respect to rabies infection among both among wild and domestic animals, recent years has shown an increase in the numbers and species affected by the virus. Cases of human infection were registered as well. No control of rabies infection has currently been organized. Omsk, Novosibirsk and Kemerovo regions, Altai Territory and Gorny Altai Republic are the most heavily infected regions known in Siberia. The analysis of the increased number of cases of rabies virus in the Novosibirsk region revealed significant differences between rural and urban types of rabies. In rural areas rabies virus was most frequently detected in wild carnivores (39.8%) and less frequently in domestic animals. The rural-type rabies virus was detected more frequently in cats and less frequently in dogs and rodents (Shestopalov A.M. et al., 1998, 1999). Due to unpredicted consequences, the possibility of the spread of rabies and potentially other Lyssaviruses by rodents should be analyzed in a detailed and large-scale study.
According to the data of the State Sanitary Inspection, rabies morbidity rate for the year 2001 in Russia increased four-fold in comparison with the year 2000. Higher morbidity rates among animals resulted in an increased number of humans bitten by sick animals: 400,000 – 450,000 inpiduals suffered from bites in the years 1997-2000. During only four months in 2002, 67 cases of the disease were registered in animals in Western Siberia (2, 3). That’s why the study of natural foci of rabies virus circulation and the detection of foci of other Lyssiaviruses in this region are undoubtedly of great importance.
To achieve the specified goals of the project, activities will include carrying out epidemiological studies in the territories of the south regions of Western Siberia as well as determination of natural foci of Lyssavirus circulation. Initial project activities will include the sterile collection of cerebellum and brain stem from animals suspected of rabies infection in the above regions of Western Siberia. Tissues will be split into two groups and properly preserved. Flourescent antibody microscopy will be employed to screen for the viruses. Positive preserved samples will be used to obtain viral isolates. Direct viral sequencing by RT-PCR will occur from stored tissue of FA positive animals. Additionally, virus will be inoculated intracerebrally to suckling mice or a monolayer of BHK-21 cell culture or propagated on mouse neuroblastoma cells for subsequent analysis.
Sequencing of the genome fragment coding for the nucleoprotein (N) will be carried out for the obtained viral isolates by RT-PCR. Selection of N gene is explained by its coding for the inner protein involved in the regulation of transcription and replication, which makes it an important factor in Lyssaviruses’ adaptation to the host (Kissi B., 1995). Primary structures of the nucleoprotein gene of the obtained isolates will be compared by computer analysis (Gene Bank) with primary structures of this gene in known Lyssaviruses. The obtained data will allow the determination of genotypes of Lyssaviruses circulating in the territory of Western Siberia, their phylogenetic relationships with known Lyssaviruses, their epidemic potential and vectors of transmission in this region. These results should supplement the data bank of primary structures of Lyssaviral genomes.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.