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At least 253 records · Page 14Linked to original sources

[The exchange of the tick-borne encephalitis virus between ixodid ticks feeding jointly on animals with a subthreshold level of viremia].

Experiments with narrow-placed-together groups of infected and noninfected tick feedings of aviremic animals proved a new way of infection for the intact specimens through the infected saliva of infected ticks excreted in the common focus of the skin inflammation. This way of the virus transmission is proposed to be nominated as transptialonic (according to the Greek word "ptialon" or saliva). It is also recommended to check up the density of ticks on the hosts and designate it as an agglomeration index.

Animals↗

A tick B-cell inhibitory protein from salivary glands of the hard tick, Hyalomma asiaticum asiaticum.

Some studies done to date suggest that B-cell inhibitory factor occurred in tick saliva. In this study, a novel protein having B-cell inhibitory activity was purified and characterized from the salivary glands of the hard tick, Hyalomma asiaticum asiaticum. This protein was named B-cell inhibitory factor (BIF). The cDNA encoding BIF was cloned by cDNA library screening. The predicted protein from the cDNA sequence is composed of 138 amino acids including the mature BIF. No similarity was found by Blast search. The lipopolysaccharide-induced B-cell proliferation was inhibited by BIF. This is the first report of the identification and characterization of B-cell inhibitory protein from tick. The current study facilitates the study of identifying the interaction among tick, Borrelia burgdorferi, the causative agent of Lyme disease, and host.

Amino Acid Sequence↗

Co-feeding ticks: Epidemiological significance for tick-borne pathogen transmission.

Until recently, the transmission of tick-borne pathogens via vertebrates was thought to depend on the development of a systemic infection in the vertebrate hosts. Pathogen transmission has now been shown to occur between infected and uninfected ticks co-feeding in time or space in the absence of a systemic infection, originally for viruses, but now also for bacteria. The epidemiological consequences of this new non-systemic transmission pathway necessitate a major reassessment of the components and dynamics of tick-borne pathogen enzootic cycles. Here Sarah Randolph, Lise Gern and Pat Nuttall show that a much wider range of natural hosts than was previously recognized may contribute significantly to the transmission of tick-borne diseases, and compare quantitatively the relative contributions made by the systemic and non-systemic transmission pathways.

Journal Article↗

[Forest tick Ixodes ricinus (Ixodidae) in the foci of tick-borne borreliosis of the northwestern part of the Moscow region].

Monitoring studies during 1996-2001 have shown a natural foci of tick-borne borreliosis with high abundance of Ixodes ricinus and high infection rate with an agent: 19.5-38.4 tick individuals per 1 km of route, infection rate 18.0 +/- 1.7-22.5 +/- 1.5%. A risk to be infected with the Lyme disease in the ricinus focus of the tick-borne borreliosis during the epizootic season did not vary much during the period of study, 3.5-8.2 in different year, mean 6.0 infected ticks per 1 km of route.

Animals↗

Isolation of Eyach virus (Reoviridae, Colorado tick fever group) from Ixodes ricinus and I. ventalloi ticks in France.

During the spring of 1981, two strains of an identical virus were isolated in Mayenne, France, from Ixodes ricinus L. and Ixodes ventalloi Gil Collado, parasiting a wild rabbit (Oryctolagus cuniculus L.). Virological and serological results indicated that these strains belong to the Colorado tick fever serogroup and are indistinguishable from Eyach virus, a tick-borne virus previously described from West Germany. Study of dsRNA PAGE profiles confirmed these conclusions. The morphology and morphogenesis of French isolates were studied in infected suckling mouse brains showing some peculiar features previously described for Colorado tick fever virus. The importance of the isolation of Eyach virus in France is discussed.

Animals↗

Detection of tick-borne encephalitis virus RNA in ticks (Ixodes ricinus) by the polymerase chain reaction.

A polymerase chain reaction for the detection of tick-borne encephalitis virus (TBEV) RNA in ticks was developed. Two pairs of primers for nested PCR were selected from the 5'-NCR and the 5'-terminus of the C protein coding region, which are highly conserved among the TBEV isolates sequenced so far. The sensitivity of the nested PCR was tested by dilution experiments of a TBEV positive brain suspension. The specificity of the PCR products was confirmed by Southern blotting. In a pilot study, 60 homogenates of 7200 ticks (I. ricinus) were examined by PCR. Two homogenates were found positive. The PCR for TBEV RNA appears to be a valuable method to define endemic areas of TBE.

Animals↗

Tick infestation patterns and prevalence of Borrelia burgdorferi in ticks collected at a veterinary clinic in Germany.

A total of 4803 domestic and wild animals which were presented for examination at a veterinary clinic in north Baden, Germany over a period of 1 year were examined for tick infestation. A total of 434 nymphal and adult ticks were collected from 175 hosts. Ticks found belonged to the species Ixodes ricinus (385), Ixodes hexagonus (48), and Ixodes ventalloi (one). The polymerase chain reaction was used to examine 132 I. ricinus and 21 I. hexagonus for the presence of Borrelia burgdorferi. Twenty-two per cent of adult I. ricinus were infected as were one female and one larval I. hexagonus.

Animals↗

The importance of tick-borne encephalitis virus RNA detection for early differential diagnosis of tick-borne encephalitis.

BACKGROUND: Tick-borne encephalitis virus (TBEV) is one of the most important causes of human viral infections of the central nervous system in Europe. Currently, the diagnosis of TBE is based on the demonstration of specific antibodies in patient's serum, which appear only several weeks after the infection. OBJECTIVE: To determine how successfully can viral RNA be detected by RT-PCR in the samples of body fluids of patients with TBE prior to and after the appearance of antibodies. STUDY DESIGN: Serum, whole blood and CSF samples from 34 patients with a serologically confirmed TBE were collected. Samples were tested for the presence of TBEV RNA by using RT-PCR method. RESULTS: Viral RNA was detected in all blood and serum samples collected before the development of antibodies. After the appearance of IgM antibodies, the number of positive samples dropped by at least one third. After the development of IgG antibodies, only 3% of serum and 16% of blood samples tested positive for viral RNA. Samples of cerebrospinal fluid were shown to be inappropriate for the molecular diagnosis of TBE using this assay, since only one sample (10%) that was collected in the sero-negative phase of disease was found positive by the PCR assay. CONCLUSIONS: RT-PCR is an efficient method for an early detection of TBEV in blood and serum samples collected prior to the appearance of antibodies. This method can be of valuable use for a differential diagnosis of TBEV infection in patients with febrile illness after a tick bite, particularly in regions where more than one tick-transmitted diseases are endemic.

Adolescent↗

A cross-reactive tick cement antigen is a candidate broad-spectrum tick vaccine.

Truncated constructs of 64P (64TRPs), a secreted cement protein from salivary glands of the tick Rhipicephalus appendiculatus, provided cross-protection against Rhipicephalus sanguineus and Ixodes ricinus, apparently by targeting antigens in the midgut and salivary glands of adults and nymphs, causing mortality. Tick feeding on 64TRP-immunised animals stimulated local inflammatory immune responses (involving basophils, eosinophils, lymphocytes, mast cells, macrophages and dendritic-like cells) that boosted the immune status of vaccinated animals. The vaccine trial results, and antigenic cross-reactivity of 64TRPs with R. sanguineus, I. ricinus, Amblyomma variegatum and Boophilus microplus, indicate the potential of 64TRPs as a broad-spectrum anti-tick vaccine.

Animals↗

A nested RT-PCR for the detection of tick-borne encephalitis virus (TBEV) in ticks in natural foci.

We have developed a sensitive nested reverse-transcriptase polymerase chain reaction assay (n RT-PCR) for the detection of the tick-borne encephalitis virus (TBEV) RNA, especially in ticks. The primer pairs were selected from the 5'-terminal noncoding region, a highly conserved part of the virus. The specificity was tested by computer homology searches of sequences as well as by the sequencing of the first and second amplificate, by Southern blot hybridization with a DIG-labelled oligonucleotide probe, and by restriction enzyme analysis. The method has proved to be very sensitive. The detection limit is about 20 fg of TBEV RNA per PCR run (25 microliters), or a single positive tick, i.e. (adult or nymph). The method can be used for comparative studies of the epidemiological situation, as well as for the screening of natural foci for the presence and circulation of TBEV or for the detection of TBEV-genome-sequences in clinical materials.

Animals↗

GIS tools for tick and tick-borne disease occurrence.

Geographic information systems (GIS), their fundamental components and technologies are described. GIS is a computer-based system enabling the storage, integration, query, display and analysis of data using information on data location. Further, remote sensing (RS) methods and their application in landscape characterization are described. Landscape pattern analysis, combined with statistical analysis, allows the determination of landscape predictors of disease risk. This makes RS/GIS a powerful set of tools for disease surveillance, enabling the prediction of potential disease outbreaks and targeting intervention programs. The 'pre-GIS era' is briefly described including the early mapping of tick distribution, analyses and the display of biogeographical and medical data. The theory of natural focality of diseases (NFD) is explained and its significance in tick-borne diseases (TBD) research is discussed. Many problems of tick ecology and TBD epidemiology and epizootology have been addressed by means of GIS and examples of these studies are presented and discussed.

Animals↗

Resistance to ixodid tick infestation induced by administration of tick-tissue culture cells.

Primary tissue culture cells of developing larvae of Amblyomma americanum were administered to guinea-pigs never previously exposed to ixodid ticks. Guinea-pigs were given 1 X 10(6) primary culture cells on Days 0, 7 and 21 by subcutaneous injection and challenged with male and female A. americanum on Day 35. A significant degree of induced host tick resistance was expressed by reduced engorgement weight of females, reduced oviposition by those females which did obtain a blood meal, and by death of ticks at the attachment site. Resistance induced by A. americanum primary culture cells stimulated a significant degree of resistance to infestation with Dermacentor andersoni adults.

Animals↗

Tick-borne encephalitis virus infections in Lithuanian domestic animals and ticks.

In order to obtain information about the distribution of tick-borne encephalitis virus (TBEV) in Lithuania, sera of domestic animals were screened for TBEV antibodies by haemagglutination inhibition test. Samples were collected in 2001 from 423 cows, 561 goats and 118 sheep during a prophylactic examination or vaccination by a local veterinary specialist. In addition, a total of 3234 Ixodes ricinus ticks in 436 pools were collected and tested by RT-PCR for the presence of TBEV RNA (detailed analysis with genetic characterization is published separately [Han et al, J Med Virol 2005 (in press)]). Domestic animal sera from 8/18 districts were positive with an overall seropositivity of 1.7% with considerable regional differences. Sheep from the Radviliskis region had the highest seropositivity rate (16%). In comparison, the proportion of tick pools positive for TBEV-RNA was 1.38%, ranging from 1.03% in Panavezys, 3.33% in Siauliai to 16% in Radviliskis.

Animals↗

Detection of ehrlichial DNA in Haemaphysalis ticks recovered from dogs in Japan that is closely related to a novel Ehrlichia sp. found in cattle ticks from Tibet, Thailand, and Africa.

Tick DNA samples from dogs in Japan were examined for Ehrlichia infection by 16S rRNA gene-based PCR and sequencing. Three positive samples were detected from Haemaphysalis ticks, and higher levels of similarity (98.46 to 99.06%) were found to recently detected Ehrlichia spp. from cattle ticks in Tibet, Thailand, and Africa.

Africa↗

Report on ticks collected in the Southeast and Mid-West regions of Brazil: analyzing the potential transmission of tick-borne pathogens to man.

Specimens of ticks were collected in 1993, 1996, 1997, and 1998, mostly from wild and domestic animals in the Southeast and Mid-West regions of Brazil. Nine species of Amblyommidae were identified: Anocentor nitens, Amblyomma cajennense, Amblyomma ovale, Amblyomma fulvum, Amblyomma striatum, Amblyomma rotundatum, Boophilus microplus, Boophilus annulatus, and Rhipicephalus sanguineus. The potential of these tick species as transmitters of pathogens to man was analyzed. A Flaviviridade Flavivirus was isolated from Amblyomma cajennense specimens collected from a sick capybara (Hydrochaeris hydrochaeris). Amblyomma cajennense is the main transmitter of Rickettsia rickettsii (=R. rickettsi), the causative agent of spotted fever in Brazil. Wild mammals, mainly capybaras and deer, infested by ticks and living in close contact with cattle, horses and dogs, offer the risk of transmission of wild zoonosis to these domestic animals and to man.

Animals↗

Tick trouble: overview of tick-borne diseases.

Tick-borne diseases can be severe or even fatal, but when identified early, most can be easily treated. Tick-borne diseases often present with nonspecific symptoms. Therefore it is important for the primary care physician to be familiar with the epidemiology of these diseases and their presentations. Although Lyme disease is the most common and well-known of the many tick-borne diseases, Rocky Mountain spotted fever, ehrlichiosis, and babesiosis are also threats throughout the United States.

Animals↗

[Ixodes tick-borne borreliosis and tick-borne encephalitis in the Udmurt republic: retrospective analysis of their spread].

The primary clinical-anamnestic and laboratory data on 1,062 cases, registered in Udmurtia in 1965-1968 and caused by the bites of taiga ticks (ixodes persulcatus), were retrospectively analyzed. The study revealed that not less than 27% of these cases could be regarded as cases of Ixodes tick-borne borreliosis (ITBB); formerly they were classified with tick-born encephalitis (TBE) or diseases of unclear etiology. The spread of ITBB on the territory of the Udmurt Republic was shown to be similar to that of TBE.

Animals↗