Genetic diversity and geographic distribution of hantaviruses in Russia

Haemorrhagic fever with renal syndrome (HFRS) is the most prevalent zoonotic disease in Russia. It is caused by several hantavirus species hosted by small rodents. We describe spatial and temporal patterns of HFRS incidence in the Russian Federation, and the geographic distribution of prevalent hantavirus species: Puumala (PUUV) and Dobrava (DOBV). Partial sequencing of nucleocapsid and glycoprotein genes of 117 PUUV strains and 78 DOBV strains revealed several distinct genetic subgroups. The RNA of Volga PUUV subgroup was detected in patients with HFRS and bank voles Myodes glareolus in the Volga Federal District, where the highest HFRS incidence rate has been registered yearly. The RNA of Siberian PUUV subgroup was found in M. glareolus in the trans-Ural Tyumen and Omsk Provinces, where human HFRS cases have been rare. During an HFRS outbreak in 2007 in the Central Federal District, when more than 1000 patients were affected, specific subgroups of DOBV were discovered in patients and rodents, mainly in the striped field mouse Apodemus agrarius. DOBV strains might have 8–9% of nucleotide difference although they were collected at places separated by 30–100 km. The RNA of a unique DOBV subgroup was discovered in the southern semi-desert Astrakhan Province, mainly in A. agrarius and tamarisk jird Meriones tamariscinus. No human HFRS cases were diagnosed in this province. Russian PUUV and DOBV strains have no close homologues among European strains. Our DOBV strains might be genetically grouped together with Central European DOBV strains isolated from A. agrarius, but not from Apodemus flavicollis. The Volga PUUV subgroup is to some extent similar to Baltic PUUV strain, and Finnish PUUV strains resemble the strains from the Siberian PUUV subgroup. Thus, PCRbased monitoring and typing provided the opportunity to delineate and expand the area of hantaviruses in Russia and to identify their new genetic variants.