Tick-borne encephalitis complex (flavi) viruses

A flavivirus infection of the central nervous system characterised by a biphasic meningoencephalitis.

Transmission is usually by hard ticks of the Ixodes genus. It can also be acquired from consumption of raw (unpasteurised) milk or dairy products.

Disease onset is 4 to 28 days after a bite from an infected tick. Diagnosis is made based on immune status; seasonality; geographical, animal, and arthropod exposures; clinical findings; and radiographic abnormalities.

Treatment consists of supportive care and management of complications. Aciclovir is given empirically until herpes simplex/varicella zoster infection is ruled out.

Most patients recover fully without long-term sequelae.

Four widely used vaccines in paediatric and adult populations are available in Canada, Europe, and Russia.

Tick-borne encephalitis (TBE) is a flavivirus infection of the central nervous system, characterised by a biphasic meningoencephalitis.[1]Hawker J, Begg N, Blair I, et al. Communicable disease control and health protection handbook. 3rd ed. Oxford: Blackwell; 2012. It is transmitted usually by hard ticks of the Ixodes genus.[2]Barlow G, Irving WL, Moss PJ. Infectious diseases and tropical medicine. In: Kumar P, Clark M, eds. Kumar & Clark’s clinical medicine. 9th ed. London: Elsevier; 2016. Disease onset is 4 to 28 days after a bite from an infected tick.[2]Barlow G, Irving WL, Moss PJ. Infectious diseases and tropical medicine. In: Kumar P, Clark M, eds. Kumar & Clark’s clinical medicine. 9th ed. London: Elsevier; 2016. TBE can also be acquired from consumption of raw (unpasteurised) milk or dairy products.[3]Centers for Disease Control and Prevention. Yellow Book. Chapter 3 - tickborne encephalitis. July 2015. http://www.cdc.gov/ (last accessed 4 October 2016). http://wwwnc.cdc.gov/travel/yellowbook/2016/infectious-diseases-related-to-travel/tickborne-encephalitis