Tick-Borne Encephalitis Virus Structural Proteins Are the Primary Viral Determinants of Non-Viraemic Transmission between Ticks whereas Non-Structural Proteins Affect Cytotoxicity.

Over 50 million humans live in areas of potential exposure to tick-borne encephalitis virus (TBEV). The disease exhibits an estimated 16,000 cases recorded annually over 30 European and Asian countries. Conventionally, TBEV transmission to Ixodes spp.

Evaluation of chimeric yellow fever 17D/dengue viral replication in ticks.

Chimeric yellow fever 17D/DENV-1-4 viruses (CYD-1-4) have been developed as a tetravalent dengue vaccine candidate which is currently being evaluated in efficacy trials in Asia and America. While YF 17D and DENV are mosquito-borne flaviviruses, it has been shown that CYD-1-4 do not replicate after oral infection in mosquitoes and are not transmitted to new hosts. To further document the risk of environmental dissemination of these viruses, we evaluated the replication of CYD-1-4 in ticks, the vector of tick-borne encephalitis virus (TBEV), another member of the flavivirus family.

Effect of saliva from horse fly Hybomitra bimaculata on kinetic properties of Na,K-ATPase: possible role in regulation of relaxation.

The possible involvement of salivary gland extract (SGE) from horse flies in modifying hyperpolarization and relaxation via alterations in functional properties of sarcolemmal Na,K-ATPase in the host tissue was tested in vitro by application of various amounts of SGE from Hybomitra bimaculata.SGE in the amount of 3 µg proteins representing approximately the equivalent of one salivary gland of Hybomitra bimaculata induced a stimulatory effect on Na,K-ATPase at all ATP concentrations applied. This effect resulted from the improved ATP-binding site affinity in the Na,K-ATPase molecule, as implicated by the reduction in K(M).

Non-hemagglutinating flaviviruses: molecular mechanisms for the emergence of new strains via adaptation to European ticks.

Tick-borne encephalitis virus (TBEV) causes human epidemics across Eurasia. Clinical manifestations range from inapparent infections and fevers to fatal encephalitis but the factors that determine disease severity are currently undefined. TBEV is characteristically a hemagglutinating (HA) virus; the ability to agglutinate erythrocytes tentatively reflects virion receptor/fusion activity.

Blackbirds and song thrushes constitute a key reservoir of Borrelia garinii, the causative agent of borreliosis in Central Europe.

Blackbirds (Turdus merula) and song thrushes (Turdus philomelos) were found to carry 95% of all spirochete-infected tick larvae among 40 bird species captured in Central Europe. More than 90% of the infections were typed as Borrelia garinii and Borrelia valaisiana. We conclude that thrushes are key players in the maintenance of these spirochete species in this region of Central Europe.

Variegin, a novel fast and tight binding thrombin inhibitor from the tropical bont tick.

Tick saliva contains potent antihemostatic molecules that help ticks obtain their enormous blood meal during prolonged feeding. We isolated thrombin inhibitors present in the salivary gland extract from partially fed female Amblyomma variegatum, the tropical bont tick, and characterized the most potent, variegin, one of the smallest (32 residues) thrombin inhibitors found in nature. Full-length variegin and two truncated variants were chemically synthesized.

An attempt to control a natural focus of leptospirosis grippotyphosa by rodenticide--a long-term study (1977-2004).

The purpose of the study was to suppress a known natural focus of field fever exerting an influence on animal hosts of leptospires--small terrestrial mammals (s.t.m.

First report of Anaplasma phagocytophilum and its co-infections with Borrelia burgdorferi sensu lato in Ixodes ricinus ticks (Acari: Ixodidae) from Republic of Moldova.

We examined 198 questing Ixodes ricinus ticks collected in Chisinau City, Republic of Moldova by PCR assays for Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato and co-infection of both pathogens, which were detected in 9%, 25.2% and 2.5% of tested ticks, respectively.

Quality control assessment for the serological diagnosis of tick borne encephalitis virus infections.

Background: The diagnosis of tick borne encephalitis (TBE) is mainly based on the demonstration of specific antibodies in serum when neurological disease is manifested. Improving diagnostics is the most important step in detecting and dealing with these pathogens. Quality control measures are essential for TBE diagnosis.

Quality control assessment for the PCR diagnosis of tick-borne encephalitis virus infections.

Background: Reverse transcriptase-polymerase chain reaction (RT-PCR) is an efficient method for the early detection of tick-borne encephalitis virus (TBEV) RNA in blood and serum samples taken prior to the appearance of antibodies. Improved diagnostics are critical for optimally detecting and managing TBE infections and quality control measures are therefore essential.

Objective: To assess the diagnostic quality of laboratories by performing an external quality assurance (EQA) programme for the molecular detection of TBE infections.

Borrelia afzelii gene expression in Ixodes ricinus (Acari: Ixodidae) ticks.

Spirochetes belonging to the Borrelia burgdorferi sensu lato (s. l.) complex have evolved remarkable ability to survive in diverse ecological niches during transmission cycles between ticks and vertebrate hosts by variable gene expression.

An antivector vaccine protects against a lethal vector-borne pathogen.

Vaccines that target blood-feeding disease vectors, such as mosquitoes and ticks, have the potential to protect against the many diseases caused by vector-borne pathogens. We tested the ability of an anti-tick vaccine derived from a tick cement protein (64TRP) of Rhipicephalus appendiculatus to protect mice against tick-borne encephalitis virus (TBEV) transmitted by infected Ixodes ricinus ticks. The vaccine has a "dual action" in immunized animals: when infested with ticks, the inflammatory and immune responses first disrupt the skin feeding site, resulting in impaired blood feeding, and then specific anti-64TRP antibodies cross-react with midgut antigenic epitopes, causing rupture of the tick midgut and death of engorged ticks.

Vasotab, a vasoactive peptide from horse fly Hybomitra bimaculata (Diptera, Tabanidae) salivary glands.

Horse flies feed from superficial haematomas and probably rely heavily on the pharmacological properties of their saliva to find blood. Here we describe the first evidence of vasodilators in horse fly Hybomitra bimaculata (Diptera, Tabanidae) salivary gland extract and clone and express one of the active peptides (termed vasotab). Physiological tests using crude salivary gland extracts and reverse-phase HPLC fractions demonstrated positive inotropism in isolated rat hearts, vasodilatation of coronary and peripheral vessels, and Na, K-ATPase inhibition.

Central European Dobrava Hantavirus isolate from a striped field mouse (Apodemus agrarius).

Dobrava virus (DOBV) is a hantavirus that causes hemorrhagic fever with renal syndrome (HFRS) in Europe. It is hosted by at least two rodent species, Apodemus flavicollis and A. agrarius.

First molecular identification of human Dobrava virus infection in central Europe.

Viral RNA was amplified by reverse transcription-PCR from a patient suffering from hemorrhagic fever with renal syndrome (HFRS) in Germany. The virus strain could be assigned to the Dobrava hantavirus (DOBV). This is the first molecular identification of human infection by DOBV in central Europe and the first proof that a virus strain related to the DOBV-Aa lineage, carried by Apodemus agrarius rodents, is able to cause HFRS.

An inhibitor of thrombin-stimulated blood platelet aggregation from the salivary glands of the hard tick Amblyomma variegatum (Acari: Ixodidae).

The tropical bont tick, Amblyomma variegatum can cause intense skin irritation and inflammation and bites that often develop into septic wounds or abscess in their host. Crude salivary gland extract (SGE) of partially engorged A. variegatum females as well as SGE protein fractions purified by three-step reverse phase HPLC procedure were tested for their anti-aggregatory effect on isolated human blood platelets stimulated with thrombin and compared with the effect of recombinant hirudin.

Association of Borrelia garinii and B. valaisiana with songbirds in Slovakia.

In Europe, 6 of the 11 genospecies of Borrelia burgdorferi sensu lato are prevalent in questing Ixodes ricinus ticks. In most parts of Central Europe, B. afzelii, B.

Genetic interaction between distinct Dobrava hantavirus subtypes in Apodemus agrarius and A. flavicollis in nature.

Dobrava virus (DOBV) occurs in two different rodent species, Apodemus flavicollis (DOBV-Af) and A. agrarius (DOBV-Aa). We sequenced the S and M genomic segments from sympatric DOBV-Af and DOBV-Aa strains which fell into two distinct genetic lineages.

Tick-borne encephalitis virus foci in Slovakia.

Tick-borne encephalitis (TBE) virus as a typical arbovirus relies on two types of hosts for its survival: ticks act both as virus vectors and reservoir hosts, and vertebrates amplify the virus infection by acting as a source of infection for feeding ticks. Longitudinal monitoring of TBE virus in ticks and vertebrate hosts including humans over a period of 40 years resulted in the identification of the areas of Slovakia where TBE virus is endemic. These are concentrated to the western, southern, and eastern parts of the country.

The key roles of selection and migration in the ecology of Lyme borreliosis.

The roles of selection and migration of B. burgdorferi s. l.