Suspected Neuro-invasive Powassan Virus Infection in a Pediatric Patient

Powassan virus lineage II (POWV), also known as deer tick virus, is an emerging tick-borne pathogen transmitted by Ixodes scapularis, the natural vector for the organisms that causes Lyme disease, babesiosis, and anaplasmosis. POWV is the only tick-borne flavivirus in North America known to cause disease in humans. We present a suspected pediatric case of POWV infection in northern Wisconsin.

Comparison of tick-borne encephalitis between children and adults-analysis of 669 patients

The aim of our study was to compare the course of TBE in children and adults. A retrospective analysis of the medical records of 669 patients was performed. The patients were categorized into 2 groups: Group I with 68 children and group II with 601 adults. TBE symptoms in children were milder compared with adults, with meningitis in 97% of cases. In adults, meningoencephalitis and meningoencephalomyelitis made up 49.26% of cases. Nausea and vomiting are more frequent in children, while neurological manifestations are more frequent in adults. There were no differences in CSF pleocytosis at the onset of disease in both groups, while CSF protein concentration was higher in adults. Children treated with corticosteroids over 7 days had higher checkup pleocytosis than pleocytosis at the onset of disease compared with adults. Corticosteroid use prolongs the disease duration but does not influence the development of TBE sequelae. Children had more favourable outcomes than adult patients.

Case report: Tick-borne encephalitis virus infection in beneficiaries of the U.S. military healthcare system in southern Germany

Tick-borne encephalitis (TBE) is caused by a flavivirus usually transmitted to humans via the bite of an infected Ixodes ricinus tick. The disease is endemic to central Europe, including Germany where it is a potential threat to U.S. service members and other beneficiaries. This report describes 3 cases of TBE in persons living during 2017 and 2018 in the region of Germany with the highest incidence of TBE: a 36-year-old active duty service member and 2 non-service member beneficiaries aged 17 and 7 years. Each patient presented with debilitating symptoms and, following recovery from their acute illnesses, experienced troubling sequelae for months afterward. The nature of their initial illnesses varied from one another, as did the length and nature of their sequelae. The criteria for diagnosing TBE based upon clinical symptoms and laboratory test results are described. Preventive strategies for protecting residents in Germany from TBE include measures to avoid tick bites. The potential for use of the TBE virus vaccine, not Food and Drug Administration- approved in the U.S. but available in Europe, is discussed.

Polio-Like Manifestation of Powassan Virus Infection with Anterior Horn Cell Involvement, Canada

Evidence of spinal cord involvement in Powassan virus infection is largely limited to mouse models. We report a case of a polio-like illness caused by Powassan virus infection in a 62-year-old man in Canada. Magnetic resonance imaging showed T2 hyperintensities in the anterior horns of the cervical spinal cord.

[Investigation of Therapeutic Efficacy of Triazavirin Against Experimental Forest-Spring Encephalitis on Albino Mice]

The comparative study of the therapeutic efficacy of Triazavirin against experimental Forest-Spring encephalitis on albino mice vs. the active drug Ribavirin® showed that in high doses (200-400 mg/kg) Triazavirin moderately protected the infected animals. A significant increase of the animal lifespan in the test groups (from 4.1 to 4.8 days) and a statistically (p ≤ 0.05) valid decrease of the virus accumulation in the target organ (the brain) were observed.

Potential role of deer tick virus in Powassan encephalitis cases in Lyme disease-endemic areas of New York, U.S.A

TOC Summary: The epidemiologic pattern and limited laboratory testing indicate that this virus lineage might account for most of these illnesses.

Powassan virus, a member of the tick-borne encephalitis group of flaviviruses, encompasses 2 lineages with separate enzootic cycles. The prototype lineage of Powassan virus (POWV) is principally maintained between Ixodes cookei ticks and the groundhog (Marmota momax) or striped skunk (Mephitis mephitis), whereas the deer tick virus (DTV) lineage is believed to be maintained between Ixodes scapularis ticks and the white-footed mouse (Peromyscus leucopus). We report 14 cases of Powassan encephalitis from New York during 2004–2012. Ten (72%) of the patients were residents of the Lower Hudson Valley, a Lyme disease–endemic area in which I. scapularis ticks account for most human tick bites. This finding suggests that many of these cases were caused by DTV rather than POWV. In 2 patients, DTV infection was confirmed by genetic sequencing. As molecular testing becomes increasingly available, more cases of Powassan encephalitis may be determined to be attributable to the DTV lineage.

[Tick-borne encephalitis with fulminant course and lethal outcome in patients after plural vaccination]

In the Kurgan region, the Siberian subtype of the tick-borne encephalitis virus (TBEV) is dominant. The vaccines prepared from Far-Eastern TBEV subtype are used in this area. Among TBE patients in 2007-2011, 23.79% were vaccinated according to complete or incomplete course. 76.9% of persons were vaccinated with Encevir vaccine, Tomsk. An unusual focal form of TBE with fulminant disease with lethal outcome was developed in a patient who was vaccinated 6 times with heterotype vaccines produced using the strains of the Far-Eastern TBE subtype. Inoculation of immunoglobulin in hospital produced aggravation of clinical symptoms, development of convulsions, brain oedema, and respiratory distress syndrome. The disease continues only 55 hours from first symptoms to fatal outcome. Siberian subtype of TBEV was isolated from patient spinal cord (Kurgan-118-2010 strain). Possible mechanisms of this disease are discussed.

[Neuroimmune aspects of the pathogenesis and nitric oxide negative effects modifying the pathogenetic treatment of tick-borne infections]

Patients with different forms of infections transmitted by Ixodidae ticks: meningeal and focal forms of tick-borne encephalitis, neuroborreliosis and mixed-infection (tick-borne encephalitis + Ixodidae tick borreliosis) were examined. CD-typing of lymphocytes in the cerebral spinal fluid (CSF), measuring blood and CSF cytokine content as well as blood nitric oxide (NO) metabolites were used to identify main pathogenetic mechanisms of the immune inflammation development in the central nervous system in tick-borne encephalitis associated with the hyperproduction of NO metabolites in the blood and CSF, inflammatory cytokine reaction and apoptosis. The antioxidant cytoflavin is suggested as a drug for pathogenetic treatment of neuroinfections with modifying effect of NO. The significantly rapid reduction (p<0.05) of general brain, focal brain and neuropsychological disorders as well as the decrease (p<0.05) in the endogenous hyperproduction of NO metabolites were found in patients (n=35) who received cytoflavin compared to those (n=35) who did not receive this drug. The authors recommend to use the drug in dose 10.0 ml once a day intravenously in drops during 7 − 10 days.

[Mexidol in the complex treatment of patients in the acute period of tick borne encephalitis]

Therapeutical action of mexidol as compared to piracetam was evaluated in groups of patients with tick borne encephalitis in the acute period of disease. Mexidol was administered as add-on to antiviral treatment in 72 patients while 89 patients received piracetam. The drugs were introduced intravenously during the first 10 days and then were given as tablets during 2 months. Based on these results, we can recommend the inclusion of mexidol in the pathogenetic treatment (fever symptoms) of tick born encephalitis. The use of mexidol as compared to piracetam led to more pronounced positive changes, higher percentage of favorable outcomes and lower frequency of residual signs.

Case report: tick-borne encephalitis in two Dutch travellers returning from Austria, Netherlands, July and August 2011

Tick-borne encephalitis (TBE) is not endemic in the Netherlands and diagnostics are seldom requested. Here, we report about the rare event of TBE in two Dutch travellers returning from Austria in July and August 2011. This report serves to create awareness among physicians to consider travel-related TBE in their differential diagnosis of patients with neurological disease returning from TBE virus endemic regions and to promote awareness among professionals advising travellers.

[Comparative study of antiviral activity of luteolin and 7,3'-disulfate luteolin]

Antiviral activity of 7,3'-disulfate luteolin, extracted from Zostera marina was studied on an experimental model of tick-borne encephalitis (TBE) in vivo and in vitro. The drug increased the survival of the experimental mice infected with TBE virus and prolonged their lifespan. It was shown that 7,3'-disulfate luteolin reduced the virus accumulation in the SPEV cells by 2.0-4.0 lg TCID50/ml.

[Interferon inductors in treatment of associative forms of tick-borne infection in children]

Thirty three children with associative forms of thick-borne infection (thick-borne encephalitis with ixodic borreliosis) were clinically observed. The disease was characterized by subfebrile temperature, moderate intoxication, rare erythema (39.5%) and frequent cardiovascular disorders with development of Lyme carditis (32.6 +/- 7.2%) and further rise of hepatomegalia in the diseases dynamics and development of meningeal symptoms. There were observed changes in the cytokine spectrum, characterized by INF-gamma high levels, and hypersecretion of the whole spectrum cytokines in the dynamics, that provided the Th2 type immune response. High clinicoimmunological efficacy of the complex therapy with cycloferon as an immunomodulator providing more balanced production of pro- and anti-inflammatory cytokines (IL-1alpha, INF-gamma and IL-10) was shown.

[Investigation of luromarin efficacy on mice with experimental tick-borne encephalitis]

Oral use of Luromarin, extracted from sea algae Zostera asiatica, was efficient in protection of mice from lethal infection induced by highly pathogenic strain of TBE virus, by extending their average lifespan. Luromarin demonstrated potentiating action in combination with ribavirin and cycloferon.

Centers for Disease Control and Prevention (CDC). Tick-borne encephalitis among U.S. travelers to Europe and Asia - 2000-2009

Tick-borne encephalitis virus (TBEV) is the most common arbovirus transmitted by ticks in Europe. Approximately 10,000 cases of tick-borne encephalitis (TBE) are reported annually in Europe and Russia. Although TBE is endemic in parts of China, information regarding its incidence is limited. TBEV is closely related to Powassan virus (POWV), another tick-borne flavivirus that is a rare cause of encephalitis in North America and Russia; TBEV and POWV can cross-react in serologic tests. Before 2000, two cases of TBE in North American travelers to Europe were reported. State health officials or clinicians send specimens from patients with unexplained encephalitis to CDC as part of routine surveillance and diagnostic testing. CDC recently reviewed all 2000-2009 laboratory records to identify cases of TBE among U.S. travelers; the five cases identified are summarized in this report. All five cases had TBEV or POWV immunoglobulin M (IgM) antibodies in serum and were confirmed as acute TBE cases by plaque-reduction neutralization tests against both viruses. All four patients who had traveled to Europe or Russia had biphasic illnesses (a common feature of TBE) and made nearly complete recoveries. The fifth patient, the first reported case of TBE in a U.S. traveler to China, had a monophasic illness with severe encephalitis and neurologic sequelae. Health-care providers should be aware of TBE, should counsel travelers about measures to reduce exposure to tick bites, and should consider the diagnosis of TBE in travelers returning from TBE-endemic countries with meningitis or encephalitis.

[The cytokine profile in the acute period of tick-borne neuroinfections in children]

Clinical peculiarities and blood levels of several cytokines were studied in 199 children, aged from 1 to 15 years, in the acute period of different tick-borne infections. The mixed infection manifested itself by the more severe progression of general clinical presentations compared to monoinfections. Etiologically unspecific changes of blood concentrations of cytokines in the acute period of the disease were found. These data were associated with different clinical forms of tick-borne infections. The decrease in the interferon gamma production was associated with the most severe disease progression with focal nervous system disorders. The use of cycloferon as immune modulator in the complex therapy led to the increase in the interferon gamma level and the decrease of general clinical manifestations during tick-borne encephalitis and mixed infection.

[The cytokine profile in the acute period of tick-borne neuroinfections in children]

Clinical peculiarities and blood levels of several cytokines were studied in 199 children, aged from 1 to 15 years, in the acute period of different tick-borne infections. The mixed infection manifested itself by the more severe progression of general clinical presentations compared to monoinfections. Etiologically unspecific changes of blood concentrations of cytokines in the acute period of the disease were found. These data were associated with different clinical forms of tick-borne infections. The decrease in the interferon gamma production was associated with the most severe disease progression with focal nervous system disorders. The use of cycloferon as immune modulator in the complex therapy led to the increase in the interferon gamma level and the decrease of general clinical manifestations during tick-borne encephalitis and mixed infection.

[Preclinical and clinical studies of the efficacy of Panavir in therapy for tick-borne encephalitis]

The antiviral activity of Panavir was studied on a model of mice infected with the strain Sofjin of tick-borne encephalitis (TBE) virus. The efficacy of Panavir was studied in the treatment of the chronic (monotherapy; 30 patients) and acute febrile and meningeal (combined therapy; n = 113) forms of TBE. Panavir was found to have a positive effect on the clinical course of TBE and the immune mechanisms of the body's protection.

[Serum and cerebrospinal fluid concentration of vitamins A, E and C in patients with tick-borne encephalitis]

We included in our study 18 patients hospitalized because of tick borne encephalitis (tbc) at the Departament of Infectious Diseases and Neuroinfections of Medical University of Bialystok. In this group, concentration of vitamins A, E and C in serum and cerebrospinal fluid (CSF) was measured before and after treatment. The control group consisted of 11 patients with no inflammatory changes in CSF were observed. We did not observe significant differences in concentration of vitamins in serum and CSF before and after treatment comparing to controls. However, we showed significant increase in concentration of vitamin E before and after treatment in both serum and CSF in patients with tbc in comparison with control group.

[Encephalomeningitis caused by Listeria monocytogenes in patient infected by TBE virus--case report]

The epidemiology of listeriosis is constantly changing towards higher incidence. The most endangered group of patients are people with immunodeficiency caused by coexisting diseases. In these cases listeriosis may take a very severe course. In this paper we present a case of a 76 year old female who suffered from encephalomeningitis caused by Listeria monocytogenes and additionally was infected by tick borne encephalitis virus and Borrelia burgdorferi.

Tick-borne encephalopathies : epidemiology, diagnosis, treatment and prevention

Tick-borne encephalopathies constitute a broad range of infectious diseases affecting the brain and other parts of the CNS. The causative agents are both viral and bacterial. This review focuses on the current most important tick-borne human diseases: tick-borne encephalitis (TBE; including Powassan encephalitis) and Lyme borreliosis. Rocky Mountain spotted fever (RMSF) and Colorado tick fever (CTF), less common tick-borne diseases associated with encephalopathy, are also discussed. TBE is the most important flaviviral infection of the CNS in Europe and Russia, with 10 000-12 000 people diagnosed annually. The lethality of TBE in Europe is 0.5% and a post-encephalitic syndrome is seen in over 40% of affected patients, often producing a pronounced impairment in quality of life. There is no specific treatment for TBE. Two vaccines are available to prevent infection. Although these have a good protection rate and good efficacy, there are few data on long-term immunity. Lyme borreliosis is the most prevalent tick-borne disease in Europe and North America, with >50 000 cases annually. Localised early disease can be treated with oral phenoxymethylpenicillin (penicillin V), doxycycline or amoxicillin. The later manifestations of meningitis, arthritis or acrodermatitis can be treated with oral doxycycline, oral amoxicillin or intravenous ceftriaxone; intravenous benzylpenicillin (penicillin G) or cefotaxime can be used as alternatives. The current use of vaccines against Lyme borreliosis in North America is under discussion, as the LYMErix vaccine has been withdrawn from the market because of possible adverse effects, for example, arthritis. RMSF and CTF appear only in North America. RMSF is an important rickettsial disease and is effectively treated with doxycycline. There is no treatment or preventative measure available for CTF.

[Intercellular adhesion molecules sICAM-1, sICAM-2, sICAM-3 and IFNgamma in neuroborreliosis and tick-borne encephalitis]

OBJECTIVE

The aim of this study was to evaluate the serum and CSF concentration of soluble intercellular adhesion molecules sICAM-1, sICAM-2, sICAM-3 and proinflammatory cytokine IFNgamma in patients with tick-borne encephalitis (TBE) and neuroborreliosis.

METHODS

The study group consisted of 40: 20 with TBE meningitis and 20 with Lyme meningitis. The serum and CSF levels of adhesion molecules and IFNgamma were determined by ELISA assay twice: before and after treatment.

RESULTS

Before treatment the concentrations of adhesion molecules and IFNgamma in serum as well as in CSF were significantly higher in both studied groups than in control group (with the exception of the serum level of sICAM-2 in TBE group). After the treatment, the serum parameters in TBE group decreased to the control level. CSF levels were also reduced, but still remained higher than in the control group. In patients with neuroborreliosis serum concentration of sICAM-1 and sICAM-2 did not change as compared with its level before treatment but other studied parameters in serum and CSF decreased significantly.

CONCLUSIONS

The results of our study confirm the participation of intercellular adhesion molecules in the pathogenesis of viral (TBE) and bacterial (neuroborreliosis) neuroinfections.

[Serum and cerebrospinal concentrations of sICAM-1 sICAM-2, sICAM-3 in neuroborrellosis and tick borne encephalitis--preliminary report]

OBJECTIVE

The aim was to evaluate the concentrations of the soluble forms of ICAM-1, ICAM-2, ICAM-3 in the serum and cerebrospinal fluid (CSF) of patients with neuroborreliosis and thick borne encephalitis before and after therapy in comparison with the control group.

MATERIAL AND METHODS

We examined 30 patients, 10 in each group: neuroborreliosis-group I (NB), tick borne encephalitis--group II (TBE) and in the control group (group K). The diagnosis of neuroborreliosis and TBE based on the clinical features was confirmed by ELISA assays: FSME Virus/TBE Virus test (VIRION, Germany) for TBE and Borrelia IgM and IgG Recombinant (Biomedica Austria) for NB. The assays of sICAM-1, sICAM-2, sICAM-3 (ELISA, Bender Med System, USA) were performed twice in group I and II: before and after 3-4 weeks long treatment and once in control group.

RESULTS AND CONCLUSIONS

Increased concentration of soluble forms of ICAM-1, ICAM-2, ICAM-3 in CSF suggest their important role in inflammatory process of viral and bacterial origin. In NB group, the serum concentrations of sICAM-1, sICAM-2 were significantly increased before and after treatment in comparison with control as well as with the analogous test results in TBE group. It may suggest NB as the part of systemic inflammation. The CSF concentration of sICAM-2 decreases after treatment in NB group in comparison with the analogous test results of TBE group. The increased CSF concentration of sICAM-2 in TBE group when compared to the CSF concentration in NB group suggest slow recovery and still persisting immunological activation in this group, even when the neurological symptoms disappeared. Increased concentrations in CSF in both diseases indicate intrameningeal activity of lymphocytes and may be a useful marker of inflammation.

[Interferon gamma concentration in the cerebrospinal fluid of patients with tick-borne encephalitis]

BACKGROUND AND PURPOSE

The purpose of this work was to evaluate interferon gamma (IFN-g) concentration in the cerebrospinal fluid of patients with diagnosed tick-borne encephalitis (TBE) early in the course of the disease and after the treatment.

MATERIAL AND METHODS

The cerebrospinal fluid of 40 patients with TBE was examined. Patients were divided into 4 groups: group 1 consisted of 13 patients with mild clinical course, group 2 included 12 patients with prolonged TBE showing the presence of inflammatory markers after the treatment, group 3 comprised 9 patients with severe TBE presenting with disorders of consciousness and group 4 consisted of 6 patients with a simultaneous B. burgdorferi infection. The cerebrospinal fluid was examined twice--during TBE diagnosing and after the treatment. IFN-g was detected by the ELISA method.

RESULTS

The concentration of IFN-g in the cerebrospinal fluid in the first examination was significantly higher in all four groups of patients in comparison with controls. After the treatment, concentration of IFN-g decreased significantly in all studied groups. The highest concentration of IFN-g at the first examination was found in group 3. The concentration of IFN-g at the second examination was similar among 4 groups of patients and in controls.

CONCLUSIONS

We found the correlation between IFN-g concentration in the cerebrospinal fluid of patients at the early stage of TBE and inflammation activity. We did not find any association between IFN-g concentration and a persistent increase of the cerebrospinal fluid parameters.

Durch Zecken �bertragene humanpathogene und bisher als apathogen geltende Mikroorganismen in Europa

The importance of tick-borne encephalitis (TBE) and Lyme borreliosis-the main European tick-borne diseases-is steadily growing. This fact is due to many different factors including climate changes. However, across Europe many other human pathogenic viruses, bacteria, and parasites are found in ticks. This article gives an overview of tick-borne human pathogenic viruses present in Europe as well as those considered nonpathogenic. It also deals with the various species of vector-competent ticks. Among these ticks, viruses from 6 families encompassing 8 genera and 35 species are found,whereby the families Flaviviridae, Bunyaviridae, and Reoviridae with the genera flavivirus, nairovirus, and orbivirus are the most prevalent. Because of their special importance Omsk hemorrhagic fever, louping-ill disease, tick-borne encephalitis, and Crimean-Congo hemorrhagic fever are discussed in detail. Although West Nile virus is mainly transmitted to man by mosquitoes, it is discussed in detail, because West Nile fever has become a good example for a new and rapidly spreading vector-borne disease in the USA and for a recurrent one in Europe. Secondly, besides the mosquito-bird cycle an interesting tick--bird cycle is emerging. The overview clearly demonstrates that in Europe (particularly in Germany) tick-borne viruses, with the exception of TBE, constitute an extremely ignored research subject. This lack of attention is in contrast to their importance and results in a lack of necessary scientific data.

Virale Enzephalitis, Frühsommer-Meningoenzephalitis (FSME)

Enzephalitiden sind eine seltene Manifestation systemischer viraler Infektionen. Die klinischen Zeichen sollten frühzeitig erkannt und supportive Maßnahmen eingeleitet werden. Durch verbesserte diagnostische Möglichkeiten (insbesondere PCR- Untersuchungen) ist die ätiologische Zuordnung einfacher geworden, allerdings sind spezifische therapeutische Möglichkeiten weiterhin beschränkt verfügbar. Der Prävention kommt entscheidende Bedeutung zu. Dies gilt auch für die durch Zecken übertragene FSME. Flaviviren gehören in der Schweiz zu den häufigsten Enzephalitiserregern. Es steht ein wirksamer Impfstoff gegen die FSME-Infektion zur Verfügung.

Pediatric tick-borne encephalitis in 371 cases from an endemic region in Slovenia, 1959 to 2000

BACKGROUND

With the exception of Lyme borreliosis, tick-borne encephalitis (TBE) is the most prevalent tick-transmitted disease in Europe. Here we report clinical and epidemiologic features of the largest number of children with TBE reported to date and the longest (i.e. 42-year) retrospective survey of pediatric TBE cases from one geographic region.

METHODS

Case records of 371 patients, age 0 to 15 years, with serologically confirmed TBE and hospitalized between 1959 and 2000 at the Department of Infectious Diseases of the General Hospital Celje, Slovenia were reviewed and analyzed.

RESULTS

Children represented 23.5% of 1578 confirmed TBE cases in the study period. Children were admitted to hospital throughout the year, but the majority were treated during summer months. In 178 (47.9%) children, a tick bite was noticed before admission. A biphasic course of illness occurred in 249 (67.1%) patients. The most common symptoms and signs of TBE were raised body temperature [>38 degrees C (n = 371)], headache and meningeal signs (n = 346), fatigue (n = 337) and vomiting (n = 327). Meningitis was diagnosed in 232 (62.5%) children, and meningoencephalitis was diagnosed in 139 (37.5%). There was a tendency for greater severity of TBE with increasing age. None of the children with TBE died, and none had permanent sequelae.

CONCLUSIONS

The results of our study indicate that pediatric TBE is relatively mild disease with favorable outcome.

[Fever after a tick bite: clinical manifestations and diagnosis of acute tick bite-associated infections in northeastern Switzerland]

BACKGROUND

Different tick-borne infections can cause an acute febrile illness. The study objectives were to investigate the clinical manifestations and diagnosis of infections among patients who presented with fever after a tick-bite, and to detect newly described pathogens, including Ehrlichia, Babesia and Rickettsia helvetica, in North-Eastern Switzerland.

PATIENTS AND METHODS

: We studied 75 patients (41 male, 34 female, median age 38 years, among them 10 children) who had fever within 3 weeks after a tick-bite. Paired sera were tested for antibodies to Borrelia burgdorferi, tick-borne encephalitis virus, Anaplasma (Ehrlichia) phagocytophila, Babesia microti, B. divergens, and Rickettsia helvetica. In addition, microscopy and polymerase chain reaction was used to detect Ehrlichia. Clinical data were obtained at baseline and at 1 and 2 year follow-up.

RESULTS

Tick-borne infections were confirmed or possible in 36 (48 %) patients: 7 (9 %) Erythema migrans, 6 (8 %) other specific manifestations of Lyme borreliosis, 6 (8 %) Lyme borreliosis presenting as non-specific febrile illness, 8 (11 %) tick-borne encephalitis, 7 (10 %) granulocytic ehrlichiosis, 1 B. microti infection in a traveler from the US and 6 (8 %) dual infections. In 8 (11 %) patients serological findings were suggesting possible acute or past R. helvetica infection.

CONCLUSION

Among patients with fever after a tick-bite, Lyme borreliosis was most frequently found. There was no evidence for babesiosis among the resident population. Serologic data suggest that human granulocytic ehrlichiosis and R. helvetica infections may be endemic in Switzerland. Among 50 % of the patients no tick-borne infections could be diagnosed.

Antibody and interleukin-12 treatment in murine models of encephalitogenic flavivirus (St. Louis encephalitis, tick-borne encephalitis) and alphavirus (Venezuelan equine encephalitis) infection

Early and sustained treatment with interleukin-12 (IL-12) ameliorated disease in a mouse model of infection with the encephalitogenic flavivirus, St. Louis encephalitis virus (SLEV, Japanese encephalitis serogroup). However, this effect was not reproduced in murine infections with either the flavivirus tick-bore encephalitis virus (TBEV) or the alphavirus Venezuelan equine encephalitis virus (VEEV). IL-12 exacerbated TBEV disease when used in conjunction with monoclonal antibody (mAb), suggesting an enhancement of immunopathology, and was without clinical effects in VEEV infection. These data confirm the need to fully understand the pathogenesis of viral infection before cytokine intervention may be employed as a broad-spectrum antiviral therapy.

Changes in immune parameters and their correction in human cases of tick-borne encephalitis

Tick-Borne Encephalitis virus (TBEV) causes dangerous central nervous system diseases in humans. General infection leads to the development of meningitis or encephalitis, which is characterized by swelling of the brain due to inflammation. Tetracyclines may act locally to moderate inflammation in the CNS. In this study, we investigated the potential clinical benefits of administering tetracycline hydrochloride to patients hospitalized due to suspected TBEV infection presenting with fever and evidence of a recent tick bite. We also characterized an acute immune response to TBEV by profiling certain cytokines and soluble receptors in Tetracycline-treated and untreated patients. Increased serum levels of TNF-alpha, IL-1 alpha and IL-6 were found in all patients at admission. Soluble receptors presented in the serum of patients in a magnitude higher levels than the corresponding cytokines and were increasing during first weak of hospitalization. Levels of IL-10 were also rising during that period. In our study tetracycline hydrochloride acted as an immunomodulator, which was able to reduce manifestations of inflammation response during TBE course; this action led to quicker improvement of symptoms and, consequently, to a faster clinical recovery. The positive result of tetracycline hydrochloride treatment was accompanied by certain particularities in the dynamics of studied cytokines and receptors: the concentrations of IL-6, IL-1 beta, TNF-alpha dropped quicker and reached lower levels, and the concentrations of sIL-6R, IL-1RA, sTNFR1 increased faster and reached higher maximum levels in the tetracycline-treated groups. Children had the highest levels of IL-6, which were not neurotoxic.

First documented case of infection with the tick-borne encephalitis virus in Vorarlberg, Austria

The present study provides evidence and documentation of the first case of infection with the tick-borne encephalitis (TBE) virus acquired in the federal state of Vorarlberg (Austria). The area in which the viral infection was discovered lies in the vicinity of Ludesch in the Illvalley (Bludenz district). In order to investigate the current state of immunity to TBE in the Vorarlberg community, a total of 218 representative sera samples taken from donors resident in the districts of this state were investigated for antibody titers (IgG) of TBE. 38% of the samples had antibody titers representative of sufficient patient immunity, with the highest immunity (63%) in persons aged 20-40 years. Donors living in urban areas had a higher percentage of immunity (43%) than those living in rural areas (33%). Further, men were more immune to infection (43%) than women (33%). The lowest level of immunity (18%) to TBE was found in the Bregenzerwald communities. Based on this report, wider criteria for administering TBE vaccines to patients from the Illvalley should be applied, in particular among the elderly and those living in rural areas.

[Comparative in vitro study of the effectiveness of various immunomodulating substances in tick-borne encephalitis]

Suppressing effect of tick-borne encephalitis (TBE) virus on expression of lymphocyte subpopulation receptors has been demonstrated in vitro. Effects of 14 immunomodulators on expression of T lymphocyte receptors under the effect of TBE virus have been compared. Anti-TBE immunoglobulin, 4-iodantipyrin, and leukinferon had the highest protective effect after a preventive injection. Thymalin and leukinferon in combination with human leukocytic interferon were the most effective within the treatment protocols. Further studies of sensitivity of immunoregulator cells to immunomodulators is recommended with the aim of adding these drugs to therapy of TBE patients.

[Effect of gentamycin on persistence of tick-borne encephalitis]

Effect of gentamicin, an aminoglycoside antibiotic, on the persistence of tick-borne encephalitis (TBE) virus in Syrian hamsters and Macaca iris in remote periods (70-434 days) after inoculation is studied. Attempts at virus isolation from animals treated with gentamicin failed. Unlike other aminoglycosides, e.g. streptomycin, gentamicin exerted no immunodepressive effect; moreover, immunocorrection was observed in some experiments on monkeys and hamsters. None of the 10 previously tested antibiotics elicited such an effect or inhibited the persisting TBE virus. Morphological study of the central nervous system in hamsters and monkeys showed that injection of gentamicin did not cause an exacerbation of chronic encephalitis. The mechanism of immunocorrecting effect of gentamicin is to be further investigated.

[Iodoantipyrine--an agent for treating and preventing tick-borne encephalitis]

The antiviral activity of iodantipyrine was studied in outbred [correction of inbred] albino mice (weight 10-12 g) infected with the Absettarov strain of the tick-borne encephalitis virus. Iodantipyrine was administered per os or parenterally and the animals were observed for 21 days. A reliable therapeutic effect was produced in 60% of mice infected with 10 DL50 of tick-borne encephalitis virus which were given the drug per os in a dose of 50 mg/kg. Preventive administration of the drug was effective in 47% of the animals.

[Some mechanisms of the action of oligonucleotides: stimulation of the immune system and decreased infection of the brain in tickborne encephalitis]

Morphological changes in the thymus, spleen, and brain are analyzed in white mice injected 16-component oligonucleotide (ON) pE16 complementary to the NS3 protein gene sequences of tickborne encephalitis (TBE) virus in doses of 1 to 0.001 nM. ON stimulated thymic and splenic cells. Besides the stimulating effect, injection of ON to mice infected with TBE enhanced the destruction of lymphocytes and boosted the macrophagal activity, which was paralleled by a decrease in the intensity of virus-specific injuries in the brain. Thus, the antiviral activity of ON may be due to not only the fact that it is complementary to the TBE virus genome, but to stimulation of the immune system, specifically, the thymus and T-related elements, as well.

Severe tick-borne encephalitis following passive immunization

We report on a 5-year-old girl with an unusually severe course of tick-borne encephalitis following passive immunization with specific hyperimmune globulin after a tick bite in an endemic area. Serial investigations of the CSF revealed intrathecal production of specific antibodies paralleled by increasing numbers of B-cells after initial T-cell pleocytosis. Focal central lesions were evident on MRI.

CONCLUSION

The severity of the presented case questions the benefit of passive immunization and rather justifies consideration of vaccine recommendation to residents and travellers to areas endemic for tick-borne encephalitis virus.

[An immunomodifier--staphylococcal anatoxin--prevents the development of immunosuppression caused by informational stress in mice]

The action of information stress for 14 days leads to the development of immunosuppression, which is manifested by the suppression of humoral response to sheep red blood cells (SRBC) and the decrease of resistance to Langat virus having low pathogenicity. As shown in this investigation, an immunomodifier, purified staphylococcal toxoid (PST), protects experimental animals from the immunosuppressive effect of information stress. After the injection of PST to stress-affected mice in doses of 15 or 1.5 binding units per animal on days 9, 11 and 13 of the experiment their humoral response to SRBC and resistance to Langat virus are partially restored (by 45-60%).

[Strategy for choosing antibiotics for treating bacterial infections associated with chronic tick-borne encephalitis]

The capacity of wide-spectrum antibiotics kefzol and ristomycin to activate the persisting tick-borne encephalitis (TBE) virus and cause an exacerbation of chronic process was investigated in Syrian hamsters in whom a prolonged (77 to 270 days) persistent TBE infection was induced by three TBE strains: Vasilchenko, V-383, and 205. The degree of antibiotic-induced activation was assessed using the criteria characterizing the reproduction and peculiarities of persisting TBE virus, immunodepression, and morphologic changes in the central nervous system. Effects of kefzol and ristomycin were compared with those of 8 antibiotics studied previously. Ristomycin, levomycetin (chloramphycin), penicillin, ampicillin (ampital), and levoridan were referred to drugs devoid of evident provoking effect. Kefzol (cefamezin), florimycin (viomycin), and kanamycin (kanamytrex) were characterized as weak activators and streptomycin and tetracycline as potent activators of the persisting TBE virus. These data may be used when selecting alternative agents for therapy of secondary bacterial infections concomitant with TBE.

[Thymus hormones in the treatment and prevention of flavivirus infection under experimental conditions]

The evaluation and selection of the preparations of thymic hormones for the treatment and prophylaxis of acute tick-borne encephalitis (TBE) caused by Far Eastern TBE virus strains have been carried out on mice under different experimental conditions. These virus strains, highly and faintly virulent with respect to noninbred mice, produce a different modulating effect of the immune responsiveness of the host, respectively suppressing or simulating immune response to sheep red blood cells. A high prophylactic effect produced by thymic hormones (having protective index equal to 50-67%) with respect to highly virulent TBE virus stains has been established, which is seemingly indicative of the fact that such course of TBE leads to the formation of the state of severe immunodeficiency due to the lesion of the thymus. A high therapeutic effect resulting from the clinical use of thymic hormones is suggested.

[The therapeutic and prophylactic effect of 4-iodoantipyrine in experimental tick-borne encephalitis]

The antiviral activity of iodantipyrine-4 belonging to the group of nonsteroid anti-inflammatory compounds was studied in inbred white mice of 10-12 g given a single subcutaneous injection of the Absettarov strain of tick-borne encephalitis virus. Iodantipyrine-4 in different doses was administered orally or parenterally, and the animals were observed for 21 days. In the group of mice infected with 10 LD50 of TBE virus which were treated with the drug orally in a dose of 50 mg/kg a reliable therapeutic effect was established in 60%, after parenteral injection in 53.4%. Prophylactic administration of the drug followed by challenge with 10 LD50 of virus was effective in 47% of mice. In the group of mice infected with 100 LD50 of the virus the therapeutic effect was observed in 38% and prophylactic in 30%. Iodantipyrine-4 was found to induce interferon production.

[Virus-induced dyslipidemias as possible risk factors in the development of somatic diseases]

Experimental and clinical studies showed a number of virus infections to be accompanied by lipidemic disorders. Experimentally, dyslipidemias were found in tick-borne encephalitis (TBE) in mice, rotavirus infection in rabbits, and amyotrophic leukospongiosis in guinea pigs. The possibility of correcting the virus-induced lipidemic disorders with an antiviral drug, lincomycin, was demonstrated in TBE in mice. Dynamic study of the lipidemic status of patients with virus hepatitis A revealed marked dyslipidemia of the atherogenic type which was stable and persisted up to the time of clinical recovery. The data obtained supplement the current concepts concerning the pathogenesis of virus infections.

[The antiviral action of medicinal plant extracts in experimental tick-borne encephalitis]

Some mechanisms of inducing resistance to experimental infection with tick-borne encephalitis virus were studied in experimental mice treated with aqueous extracts of berries of Vaccinium vitis-idaea, black currant, Vaccinium myrtillus, and of greater celandine grass. The condition of the immune system organs (spleen and thymus) after treatment with the extracts under study was analysed. A correlation was found between the degree of developing resistance to infection, virus accumulation in the brain, blood, spleen and thymus and changes in some parameters (spleen and thymus indices) of these immunocompetent organs. Possible mechanisms of induction of resistance to virus by herb extracts are discussed.

[The efficacy of lincomycin in tick-borne encephalitis]

Lincomycin was found to inhibit tick-borne encephalitis (TBE) virus. To test antiviral potential of this drug, a clinical trial was initiated entering TBE patients from known focuses of the disease (Novosibirsk, Kemerovo, Perm and Irkutsk Provinces). The drug was given to 23 patients with meningeal and meningoencephalitic TBE. A control group of 22 matched subjects received specific immunoglobulin. Resultant efficacy of lincomycin appeared not inferior to that of anti-TBE immunoglobulin. Lincomycin can be successfully introduced in the treatment of meningeal and meningoencephalitic TBE.

[Experimental phytotherapy of tick-borne encephalitis]

The virucidal effect of aqueous extracts of a number of plants was studied in tick-borne encephalitis (TBE) virus titration in SPEV cell culture in microplates, as well as their capacity to induce resistance in virus-infected mice. The aqueous extracts of ledum, motherwort, celandine, black currant, cowberry and bilberry inactivated TBE virus practically completely, and those of St. John's wort, pot marigold, tansy, chamomile, milfoil, and inula only partially. Studied in vivo, the extracts of motherwort, ledum, tansy and black currant induced resistance of mice to TBE virus infection assessed by the increased survival rate of the animals and significant prolongation of the average longevity. The degree of antiviral activity depended on the preparations used and the routes of their administration.

[The search for antibiotics not exerting activating action in the persistence of the tick-borne encephalitis virus]

Chronic tick-borne encephalitis (TBE) frequently develops in the presence of concomitant diseases requiring antibiotic therapy. Because some antibiotics, e.g. streptomycin, strongly activate persisting TBE virus, a study was carried out in search of antibiotics without the activating effect. The experiments were carried out in Syrian hamsters inoculated subcutaneously with the Vasil'chenko strain of TBE virus which at 60-348 days of the persistent infection were given florimycin, levomycetin and kanamycin. The antibiotics were administered for 3 weeks. Levomycetin showed no activating properties, while kanamycin and florimycin exerted weak activating effect on the persisting TBE virus (isolated from 5% of the specimens) without marked immunosuppressive effect or manifestation of the infection. The TBE virus strains isolated on the 205th day from the brain and 348th day from the spleen of the hamsters given kanamycin and florimycin had higher virulence than the original strain.