Frühsommermeningoenzephalitis

Abstract

Tick-borne encephalitis (TBE) is one of the most important viral infections of the human central nervous system. Approximately 10,000 cases of TBE are referred to hospitals in Europe and Asia each year. The TBE virus (TBEV) is mainly transmitted by tick bites but also occasionally by unpasteurized goat's milk. As in endemic areas on average only 1-3 % of ticks are infected with the TBEV and the clinical manifestation rate is approximately 33 %, only approximately 1 in every 100-300 tick bites leads to disease. The incubation period varies from 5-28 days and typically has a biphasic course of fever. The TBE manifests as meningitis in approximately 50 % of patients, as meningoencephalitis in 40 % and as encephalomyelitis in 10 %. The suspected diagnosis is confirmed by the demonstration of TBEV-specific IgM and IgG antibodies in serum and the presence of elevated cell counts in cerebrospinal fluid. No specific treatment for TBE is known but it can be successfully prevented by active immunization.

EAN consensus review on prevention, diagnosis and management of tick‐borne encephalitis

“…For TBE, moderately raised CSF protein and mononuclear pleocytosis ranging from 6 × 10 6 to 1200 × 10 6 cells/l but normal glucose and lactate levels are characteristic . Exceptionally, TBE has been demonstrated without CSF pleocytosis .…”

“…impaired consciousness, focal neurological signs, bradycardia, seizures or papilloedema, brain imaging is mandatory prior to lumbar puncture to exclude conditions that may increase intracranial pressure (ICP). Other contraindications include local infections at the puncture site, congenital abnormalities and coagulopathies .…”

“…However, occurrence of high fever and allergic reactions has been reported due to EnceVir (one of the two Russian vaccines) that is currently not recommended by Russian authorities for use in children up to 17 years [69]. About two-thirds of TBEV infections are asymptomatic [13,114,115]. The incubation period of TBE is on average 7-14 days after a tick bite (range 2-28 days), being shorter after milk-borne transmission.…”

“…For the disease caused by the European subtype of TBEV, a biphasic course is characteristic: the initial viremic phase presenting with fever, headache, muscle pain and fatigue, lasting 2-7 days, is followed by an afebrile period of 2-10 days. In the second phase, fever reappears and is accompanied by signs and symptoms of CNS inflammation [13,[114][115][116][117].…”

Tick-Borne Flavivirus Inhibits Sphingomyelinase (IsSMase), a Venomous Spider Ortholog to Increase Sphingomyelin Lipid Levels for Its Survival in Ixodes scapularis Ticks

“…The medically important Ixodes scapularis tick transmits a variety of pathogens that cause severe diseases in humans and animals (Labuda et al, 1996;Labuda and Randolph, 1999;Nuttall et al, 2000;Labuda, 2003, 2004;Piesman and Eisen, 2008;Neelakanta and Sultana, 2015;de la Fuente, 2018;Kim, 2019). Some of the tick-borne pathogens of human health importance are the newly emerging Powassan virus (POWV), tick-borne encephalitis virus (TBEV), Lyme disease agent Borrelia burgdorferi, rickettsial pathogens (such as Rickettsia rickettsii and Anaplasma phagocytophilum), and Francisella tularensis, a bacterium causing tularemia (Randolph et al, 1996;Sexton and Kirkland, 1998;Nuttall et al, 2000;Piesman and Eisen, 2008;Sultana et al, 2010;Valarcher et al, 2015;Vora et al, 2017;Zhou et al, 2018;Sekeyova et al, 2019;Zellner and Huntley, 2019). Ticks have evolved a myriad of strategies that allow them to get a blood meal through feeding on a vertebrate host for several days.…”