Surveillance for arboviruses in the Soviet Union: relationships between ecologic zones and virus distribution

Summary

Results are presented of a systematic search in the territory of the U.S.S.R. for natural foci of arboviruses. We used ecological surveillance of territories through different landscape zones taking into account some climatic factors, determining the distribution of vectors and vertebrate hosts and the reproduction of different arboviruses therein. Surveillance was performed from latitude 72° to 40° North in arctic, subarctic, north taiga, south taiga, leaf-bearing forest, steppe and subtropical zones. Special attention was paid to the specific features of distribution of viruses of the California and Bunyamwera serogroups. For this purpose we collected specimens for virological and serological studies. Collections were made simultaneously in each of nine meridional sections of European and Asian U.S.S.R. covering about 7.5 million km². We collected 1,256,000 mosquitoes, about 20,000 ticks, 3,500 vertebrates, more than 1,000 specimens from patients, and 20,000 serum specimens from asymptomatic humans and domestic animals. In this paper we discuss peculiarities of the distribution of arboviruses in different landscape climatic zones of northern Eurasia.