|Group:||Group IV ((+)ssRNA)|
Langat virus (LGTV) is a virus of the genus Flavivirus. For the first time Langat virus was isolated in Malaysia and Thailand. This virus is close to Omsk hemorrhagic fever virus, Kyasanur forest disease virus, Alkhurma virus, Louping ill virus and the Tick-borne encephalitis virus. The Langat virus does not pose significant epidemiological threat in comparison with TBEV. There are no known cases of human diseases associated with LGTV, however antibodies to this virus have been detected in the sera of local people.
LGTV-based vaccine 
In 1970s a live attenuate LGTV-based vaccine against tick-borne encephalitis was made. At the same time, another vaccine was tested, but the group vaccinated with the LGTV-based vaccine had the lowest level of developing infection decease. However, there were two big problems: the high level incidents of encephalitis (1:10 000) and not absolute protection from infection in endemic regions.
- Gritsun TS, Lashkevich VA, Gould EA (January 2003). "Tick-borne encephalitis". Antiviral Res 57 (1–2): 129–46. doi:10.1016/S0166-3542(02)00206-1. PMID 12615309.
- Shapoval AN, Kamalov II, Denisova EIu, Sokolova ED, Luzin PM, Shamarina AG, Gusmanova AG, Pinaeva NI (1989). "Study of the distant consequences of immunizing people with a live vaccine against tick-borne encephalitis". Tr Inst Im Pastera (in Russian) 65: 133–5. PMID 2629181.