It Is Safer To Keep Variola Virus In Fragments

Physicians have won the victory over the natural variola virus: it does not exist in nature any longer. Now, it is also necessary to destroy the viruses kept in the laboratory, however, their genetic material should be preserved. Resolution of this task in Russia is funded by the International Science and Technology Center (ISTC).

Specialists of the State Research Center of Virology and Biotechnology “Vector” (Ministry of Health of the Russian Federation) supported by the International Science and Technology Center (ISTC) disassembled into fragments complete genomes of 8 cultures of natural variola viruses. In such a form, virus’ genome can be kept for a very long time and used for research work without fear that the virus itself will get into disposal of terrorists or will “escape” the laboratory as a result of an accident.

Large-scale actions undertaken by the world community under the aegis of the World Health Organization allowed to fully eliminate natural variola. At present, natural variola viruses are preserved only in collections of two collaborative research centers: in the Center for Disease Control and Prevention (CDC) (Atlanta, USA) and in the State Research Center of Virology and Biotechnology “Vector”. Since 1980, immunization of population against natural variola virus was ceased in all countries, and the amount of people sensitive to this disease is constantly growing. Repositories of viable cultures of the virus are a source of possible biological hazard. Therefore, World Health Organization decided in 1986 that it was necessary to destroy all collections of natural variola virus’ cultures and their DNAs. Extermination is inevitable, but it will be a great loss for virology and medicine. Firstly, functioning and organization of this virus have not been studied in detail, secondly, although nobody falls ill with natural variola now, specialists should have the opportunity to develop contemporary express-diagnostics methods. To continue the research, the Russian scientists had to develop a safe way for preservation of genetic material of this virus.

The preservation problem was solved with the help of the polymerase chain reaction method. This technology allows to get copies of sufficiently expanded DNA fragments which make approximately one fifth of natural variola virus’ genome. However, such fragments can be destroyed in the course of long storage and, no matter how numerous they are, will sooner or later come to the end, and there will be no source to get new ones. Therefore, all fragments were embedded into vectorial molecules, which can be maintained and reproduced in the cells of Escherichia coli. The Novosibirsk virologists have transferred into such fragmentary collection genomes of 8 cultures of natural variola virus collected in various locations of the globe and belonging to two epidemiological types (variola major and variola minor alastrium). The museum created in such a way is a representative, safe and long-term repository of virus’ genetic information. Each construction represented in the collection is assigned its personal number and provided with a passport – description. At present, the museum is used as a basis for studying structure functional organization of individual genes, areas and the entire genome of natural variola virus. Genetic material stored in the museum is applied to create contemporary species-specific diagnostics methods, such as hybridization on microchips.