Main features of tick-borne encephalitis eco-epidemiology in Russia

Risk for Human Tick-Borne Encephalitis, Borrelioses, and Double Infection in the Pre-Ural Region of Russia

“…Because most people remove ticks promptly (within <1 day [12]), a physiologic phenomenon called reactivation, which is required for some microorganisms before infectivity is attained, does not have time to develop. The risk for clinical illness of TBE and borreliosis is largely determined by highly infected ticks (20), which always account for only a few of all infected ticks in a population (21). In addition, among I. persulcatus ticks infected by B. garinii and B. afzelii, no more than half contain spirochetes in the salivary glands after a blood meal and are capable of transmitting them to bitten people (16).…”

Epizootiological Study of Tick-Borne Encephalitis Virus Infection in Japan

“…TBEV is prevalent over a wide area of the Eurasian continent including Europe, Russia, Far-Eastern Asia and Japan [1,8,10] and has a significant impact on public health in these endemic regions. Based on phylogenetic analysis, TBEV can be divided into three subtypes, the Far-Eastern subtype, known as Russian Spring summer encephalitis (RSSE) virus, the European subtype, known as Central European encephalitis (CEE) virus, and the Siberian subtype [3][4][5].…”

Epidemiological and Ecological Studies of Tick-borne Encephalitis Virus

“…In 3 German studies, a higher prevalence of TBEV has been observed in ticks detached from humans than in field-collected ticks from the same area (Table 1) [92][93][94]. Only a small proportion of infected ticks, both from the field and from humans, appears to have a high virus titer [95,96]. How TBEV can persist at such low prevalence rates in ticks is not completely understood, but mathematical models suggests that aggregation of cofeeding ticks on host animals is crucial to maintain virus circulation, and may explain the highly focal and patchy distribution of TBEV [97].…”