The virus was first isolated in Malaysia in 1956 from a hard tick of the Ixodes genus.

The Langat virus does not pose a significant epidemiological threat in comparison with TBEV.

[2] The Malaysian strain (LGT strain TP21, also known as the Yelantsev virus) is naturally attenuated and induces neutralizing antibodies to tick-borne encephalitis virus (TBEV) and protection against other TBEV complex viruses in animals.

[3] In the 1970s a live attenuate LGTV-based vaccine against tick-borne encephalitis was made.

[4] However, there were two major problems: the relatively high rate of incidents of encephalitis (1:10,000) and lack of absolute protection from infection in endemic regions.