Epidemiologic and Clinical Aspects of Hemorrhagic Fever with Renal Syndrome in the Samara Region

Abstract

Introduction: Hemorrhagic fever with renal syndrome is the most common zoonosis in the Samara Region accounting for 90% of all zoonotic disease cases annually. Our objective was to analyze current clinical and epidemiologic data on hemorrhagic fever with renal syndrome (HFRS) in the Samara Region. Materials and methods: We conducted an epidemiologic analysis of 1,031 HFRS cases in the Samara Region in 2016–2018. The most epidemically active natural foci of HFRS were the town of Zhigulyovsk with nearby villages, the forest surrounding Samara, and the forest-steppe zone in northeastern areas. The disease was mainly transmitted in the household while cleaning of country houses (34.3%), in the forest (21.0%), suburbs (17.9%), on agricultural grounds (17.3%), in industrial settings (3.4%), and in private fruit and vegetable gardens (1.2%). The majority of HFRS cases (97.7%) were working-age adults. Results: We analyzed the results of clinical examinations of 235 patients treated in the Infectious Disease Clinic of the Samara State Medical University for HFRS of varying severity by disease phases (initial, oliguric, and polyuric). Most patients (68.5%) were admitted to the hospital on the 5th-7th day of the disease (in the beginning of the oliguric phase). The disease was characterized by an acute onset. Hyperthermia with the maximum body temperature of 40.0°C was observed in the initial and oliguric phases (100%), remaining in the phase of polyuria in 58% of severe and 33% of moderate HFRS cases. Upon admission, permanent signs of the disease, especially in severe cases, included intense general weakness, headache, and dry mouth. The headache persisted during polyuria in 68% of the patients. Half of the patients reported lower back pain already at the end of the initial phase (48%) while 93% of cases complained of lumbago during the entire phase of oliguria and the majority – in the polyuric phase (72%). Visual impairment was reported by 52% and 89% of cases with a moderate and severe disease, respectively. The severe clinical course of HFRS was noted for nose and gum bleeding in patients in the initial (about 10%) and oliguric (about 20%) phases.