Makenow et al.
First detection of tick-borne encephalitis virus in Ixodes ricinus ticks and their rodent hosts in Moscow, Russia
Ticks Tick Borne Dis. 2019, in press, DOI.org/10.1016/j.ttbdis.2019.1011265
In Russia, the TBE virus is widespread and 47 out of 85 regions are assessed TBE risk areas. However, Moscow and most districts of the Moscow Oblast are not endemic for TBE virus – the most recent confirmed TBE cases date back to 1948-1954.
In 2016, TBE was diagnosed in a 43-year old patient who was bitten by a tick in the west of Moscow in a forest park. In 2017, a 27-year-old woman was bitten by a tick in the west of Moscow in a park and developed TBE antibodies.
A total of 227 ticks were collected by flagging in areas where the two patients have been bitten. 225 ticks were identified as I. ricinus, one tick was I. persulcatus and one tick was Dermacentor reticulatus. TBE virus could be detected in five specimens. In addition, rodents were trapped alive in these areas and were analyzed for the TBE virus. In the brain of two bank voles, positive RT-PCR signals for the TBE virus were yielded and in 24 out of 28 small animals, neutralizing TBE antibodies could be detected. Six TBE virus strains were isolated, one from the female patient and four from questing ticks. The complete polyprotein gene was sequenced, and the data showed that these virus isolates belonged to the European subtype and the genome sequence of these isolates were nearly identical (99.9%). It is hypothesized that the TBE virus has recently been introduced by birds into Moscow parks.