TBEVSib

TBEV-Sib, short for tick-borne encephalitis virus Siberian subtype, is one of the lineages of Tick-borne encephalitis virus (TBEV), a positive-sense RNA virus in the Flaviviridae family. It is distinct from other TBEV subtypes such as the European and Far Eastern lineages, with genetic differences predominantly in the envelope (E) protein used for phylogenetic classification.

Geographic distribution and vectors are centered in Siberia and northern Asia, with occurrences across parts of Russia, Mongolia, and China, and reports from adjacent regions in Europe. The primary vectors are Ixodes ticks, and natural reservoir hosts include small mammals and birds. Human infections are typically incidental, arising from tick bites, though rare routes such as unpasteurized dairy products have been reported in some regions.

Clinically, TBEV-Sib infections can range from asymptomatic to neuroinvasive disease. A biphasic illness is common: an initial febrile phase followed by potential involvement of the central nervous system, manifesting as meningitis, encephalitis, or myelitis. Neurological disease carries a risk of long-term sequelae in survivors; mortality is generally low to moderate and varies by region and patient factors.

Diagnosis relies on laboratory testing, primarily serology for TBEV-Sib–specific IgM and IgG in serum or cerebrospinal fluid. Real-time RT-PCR can detect viral RNA in the early phase. Because flavivirus serology can cross-react, neutralization tests may be used to confirm the subtype.

Prevention focuses on tick avoidance and vaccination. Licensed TBE vaccines provide cross-protection against multiple subtypes and are a key public health measure in endemic areas. There is no specific antiviral treatment; management is supportive.