Introduction
Although in nature there are many species of ticks, not all of them are possible vectors of TBE: as we saw in the previous article, the most dangerous tick species for the spread of Tick-Borne Encephalitis Virus belong to the genus Ixodes (in particular Iodex ricinus) .
TBE: symptoms
To learn more: Symptoms of Tick-borne Encephalitis (TBE)
TBE is a pathology typical of adulthood; the chances of the disease also affecting children and adolescents increase during excursions or camps. Although TBE occurs particularly among adults, when the virus infects children and adolescents through the tick bite, the symptoms are milder; moreover, in the youngest patients, the disease tends to regress in a short time, with complete recovery.
The diagnosis of TBE is sometimes problematic, because the disease is asymptomatic in about 65-67% of cases. The incubation period of the virus is around 7/14 days.
In symptomatic subjects, TBE begins with high fever accompanied by general malaise, physical tiredness, back pain, headache, joint pain and nausea. Most often, the symptoms that characterize this phase (called viremic) persist for a week; then follows a period ranging from 1 to 20 days during which patients do not complain of fever. In 5-30% of TBE patients, the clinical-symptomatic picture suddenly degenerates triggering meningoencephalitis (inflammation of the meninges and brain tissue) or meningitis (inflammation of the meningeal membranes) associated with myalgia, fever, headache and photophobia. When TBE worsens, the symptoms worsen: it is not uncommon for the patient to be affected by flaccid paralysis. Most of the time, the symptoms remain for two weeks, and then slowly decline. In the more severe forms, TBE subjects can maintain neurological alterations, but only in 1-2% of cases TBE causes death (in general, occurs after 5-7 days from the onset of neurological disorders).
TBE diagnosis
As mentioned, the diagnosis is not always immediate, since most of the subjects who suffered the bite of an infected tick do not complain of any symptoms.
The hypothesized TBE diagnosis is ascertained by serum analysis, collected during the acute phase of the disease (due to the presence of IgM, virus-specific antibodies).
Particularly appropriate for the diagnosis of TBE are PCR and RT-PCR: the first is an advanced molecular biology technique capable of amplifying nucleic acid fragments, the second - standard PCR variant - allows to replicate a DNA molecule starting from a set of RNAs isolated from a particular cell.
Therapies and prevention
To learn more: Drugs to treat TBE
At the present time a suitable and completely resolving therapy for TBE has not yet been identified: in this regard, we talk about supportive therapy, a treatment based essentially on the healing of symptoms. Clearly, in the case of meningoencephalitis - a typical complication of TBE - hospitalization of the patient is required, in addition to further supportive therapy.
In order to avoid the illness in question, it is advisable to carry out a scrupulous prophylaxis: in this regard, a vaccine against TBE was created, currently on the market since 2006, although it was conceived in 2000 in Austria (Ticovac). This vaccine is recommended for all people who undertake a journey to potentially dangerous areas (where TBE is endemic), especially in the mountains, rural and wooded areas. The vaccine is administered intramuscularly, in triple administration at a distance of a few months from one another. It is estimated that the effectiveness of the TBE vaccine remains unchanged for 3 years. Nevertheless, TBE vaccination is still under study because - according to some experts - it seems that the side effects can be very unpleasant, sometimes serious (fatigue, nausea, muscle pain, low-grade fever, vomiting, skin rash, swelling of lymph nodes adjacent to the injection area, etc.).
Some TBE vaccines have been formulated that are useful for post-exposure prophylaxis, effective up to 48 hours after the infected tick bite.
