Epidemiological, ecological and clinico-laboratory characteristics of hemorrhagic fever with renal syndrome in Saint-Petersburg and suburb oleh V. V. Nechaev, I. I. Yarovayа, I. V. Gorbunova, O. V. Meo, I. P. Fedunjk, A. P. Chmir, N. C. Litvinova, I. C. Chinzeria, N. E. Chunaeva