Tick-borne encephalitis: Clinical findings and prognosis in adults

Abstract

In middle and eastern European countries, tick-borne encephalitis (TBE) is one of the most important human infections of the central nervous system. TBE virus (TBEV) is mainly transmitted by tick bites and in very rare cases by unpasteurized milk. The incubation period is on an average 7-10 days. A biphasic course of illness with a prodromal period occurs in about two third of patients. In European countries, TBE presents as meningitis in about 50 % of patients, as meningoencephalitis in 40 %, and as meningoencephalomyelitis in 10 %. The severity of TBE increases with age, in children and adolescents, meningitis is the predominant form of the disease. Long-term prognosis is unfavorable in about 40-50 % of patients who suffer from sequelae for months to years, mainly in terms of pareses, ataxia, and other gait disturbances. No specific treatment for TBE is known so far, but TBE can be successfully prevented by active immunization.

The International Scientific Working Group on Tick-Borne Encephalitis (ISW TBE): Review of 17 years of activity and commitment

“…The amount of antibody response to most foreign antigens decreases and the reactions 245 to vaccinations are generally slower, antibody titers reach lower values and decrease earlier than in 246 young people (Hainz et al, 2002; Grubeck-Loebenstein et al, 2009; Weinberger et al, 2010; 247 Goronzy and Weyand, 2013). 248The clinical manifestations encephalitis and myelitis dominate in the age group >50 years 249 (Lindquist and Vapalahti, 2008;Kaiser, 2012). Assisted ventilation is more often needed, and a 250 longer stay in the intensive car unit is more frequent.…”

“…Table 5 shows an overview of ECDC's TBE key initiatives. The incidence of TBE is clearly increasing with age (Kaiser, 2012). Additionally, with increasing 242 age the clinical course of the disease is more severe, a fact that is attributable to the aging immune 243 system.…”

Epidemiological and Ecological Studies of Tick-borne Encephalitis Virus

“…Symptomatic treatment consists of ensuring sufficient nutrition and water intake, administration of pain killers, mild nonsteroidal anti-inflammatory drugs, and if necessary, antiepilectic drugs [191]. Patients with severe CNS symptoms must be closely monitored as coma and paralysis may develop rapidly in which case artificial breathing assistance is needed [171].…”

“…To verify vaccination breakthroughs it is necessary to demonstrate production of specific IgM and IgG antibodies in CSF [191].…”

Subclinical Tick-Borne Encephalitis Virus in Experimentally Infected <b><i>Apodemus agrarius</i></b>

“…In the majority of human cases, the infection is unapparent [2]. However, some people overcome the disease after a short period of headache and fever; 10-20% of patients are hospitalized with clinical encephalitis [3], while 0.1-0.2% of cases result in chronic paralysis (usually of the arms) or death [4]. …”