Tick-borne encephalitis virus

Tick-Borne Encephalitis Virus

Tick-borne encephalitis virus (TBEV) is a virus responsible for tick-borne encephalitis (TBE), a disease affecting the central nervous system. TBEV is a member of the Flaviviridae family and is transmitted to humans through the bite of infected ticks. The virus can cause a wide range of symptoms, from mild flu-like symptoms to severe neurological damage, and in some cases, it can be fatal.

Transmission and Distribution

TBEV is primarily transmitted to humans through the bite of infected Ixodes ticks, particularly Ixodes ricinus and Ixodes persulcatus. These ticks are found in forested areas of Europe and northern Asia, from eastern France to northern Japan and from northern Russia to Albania. The virus can also be transmitted through the consumption of unpasteurized milk from infected animals.

Clinical Manifestation

The disease manifests in two phases. The first phase occurs about a week after the tick bite and presents as a nonspecific flu-like illness, with symptoms such as fever, headache, fatigue, and muscle pain. After a symptom-free period of about a week, approximately a third of infected individuals enter the second phase, which involves the central nervous system, leading to meningitis, encephalitis, or meningoencephalitis. The severity of the disease can vary significantly, from mild cases with full recovery to severe cases resulting in paralysis, permanent neurological damage, or death.

Prevention and Treatment

Prevention of TBEV infection is primarily through avoiding tick bites by wearing protective clothing, using insect repellents, and performing regular tick checks after visiting tick-infested areas. Vaccination is available and recommended for people living in or traveling to areas where TBE is common. There is no specific antiviral treatment for TBE; management of the disease focuses on supportive care to relieve symptoms.

Epidemiology

The incidence of TBE is increasing in many parts of Europe and Asia, attributed to various factors including climate change, which affects tick distribution and activity, and increased human activity in areas where infected ticks are found. Public health measures and vaccination programs are crucial in preventing TBE in endemic areas.