Tick borne Encephalitis Virus (TBEV)
The tick-borne encephalitis virus(TBEV) belongs to member of the family Flaviviridae. The TBE is an infectious disease involving the central nervous system. The three different subtypes are Western tick-borne encephalitis virus, Siberian tick-borne encephalitis virus, and Far eastern Tick-borne encephalitis virus.
Hard ticks of the family Ixodidae acts as vector and reservoir for TBEV. The major hosts are the small rodents with humans being accidental hosts. Animals serve as feeding hosts for the ticks but do not play a role in the maintenance of the virus.
The common route of infection is through a tick bite. Infection may also occur by consumption of raw milk from goats, sheep, and cows. Person to person transmission has not been reported except for transmission from infected mother to the fetus (vertical transmission).
Laboratory testing can help in diagnosing the TBEV infection. Infectolab immunoassays (that detect antibodies IgM and IgG) can be used in diagnosing the infection, while also taking the patient’s symptomology into account.
The incubation period of TBE is usually 7 and 14 days and is asymptomatic. Shorter incubation period has been reported after milk-borne exposure. The European TBE infectious in adults than in children where more frequently meningitis is observed. The symptoms in the early phase are more unspecific and may include:
headache, nausea, and/or vomiting.
Post 8 days a second phase if disease occurs in 30% of patients. The Patients may experience illness that involves the central nervous system and symptoms are like that of meningitis, encephalitis or meningoencephalitis.
In general, the mortality rate is about 1-2% with death occurring 5-7 days after the onset of the neurologic symptoms in European TBE.
There is no specific drug for TBE infection. Meningitis, encephalitis or meningoencephalitis requires hospitalization based on the severity. Corticosteroids may be considered for relief of the symptoms.