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At least 271 records · Page 15Linked to original sources
PubMedDate not supplied

[Long-term morbidity and spatial distribution of tick-borne encephalitis and ixodes tick-borne borreliosis in Udmurtia].

The paper considers the trends of morbidity due to tick-borne encephalities (TBE) and lxodes tick-borne borrelioses (lTBB) in Udmurtia during 35 years (1965-2000) and evaluates the long-term influence of measures aimed at suppressing natural foci by eliminating the basic vector on this process. For this, data on 1062 cases of fevers occurring after the bite of a tick in Udmurtia in 1965-1968, the similar data on 1509 cases in 1983-1987, and the official data on the incidence of these infections in 1996-2000 have been retrospectively analyzed. It has been shown that in Udmurtia the natural foci of lTBB coexisted with those of TBE long before the pathogens of borrelioses were described and notification of the infection of this group was initiated. In the 1990s, there was a drastic rise in the incidence of TBE and lTBB as compared with the 1960s and 1980s, which was due to an increase in the rate of contacts of the population with natural foci and to the better diagnosis of these infections. The prevalence of lTBB coincides with that of TBE. There is a long (more than 30 years) epidemiological effect in eliminating the vector Ixodes persulcatus.

Animals↗
PubMed2004

[The public health risk of ticks and tick-borne diseases in the south-eastern Poland].

The aim of the study was to estimate risk of tick-borne diseases among inhabitants of Lublin macroregion. The incidence of Lyme disease in the residents of Lubelskie Voivodeship increased from 2.9 to 6.3 in the period between 2002 and 2003. In 16% of patients studied there were systemic reactions observed after tick bite, while the local symptoms were noted in 56% of bitten subjects. Our data indicates that 59% of the respondents have poor knowledge of ticks and tic-borne diseases.

Animals↗
PubMedDate not supplied

[The location of the infecting tick bite and the severity of the course of tick-borne encephalitis].

Analysis of 846 epidemiological charts of unvaccinated tick-borne encephalitis patients in the period of 1956-1985 established that in 21% cases the disease resulted from multiple bites of the ticks, in 67.3% it occurred from single bites. In 11.7% of the patients, the bite was denied. Single infecting bites were mostly those of the head and neck (39.2% cases), especially frequent among children (84.9%). The upper part of the body and hands were bitten less frequently (16.7 and 12.5%, respectively). Other sites of the bite were reported in 6-10%. The most complicated pattern of tick-borne encephalitis is observed in case of multiple bites: two-fold increase in mortality rates compared to single bites (23.2 vs. 10.7%) and higher percent of focal forms (72.7 vs. 56.5%). In case of the single bites a certain correlation is observed between the site of the bite and the outcome of the disease: fatal outcomes are most frequent in case of the bites in the axilla, arms (14-16%), head and neck (11.2%), and less frequent in case of the bites in the lower limbs (5.9%) and groin (0). The nature of the infecting bite determines, to a great extent, the pathogenesis and outcome of the disease. The prevention of multiple bites would help considerably to reduce mortality rates.

Adolescent↗
PubMed1987

Experimental double infection with Coxiella burnetii and tick-borne encephalitis virus in Dermacentor reticulatus ticks.

Experimental parenteral inoculation of Dermacentor reticulatus ticks with the rickettsia Coxiella burnetii (C.b.) and tick-borne encephalitis (TBE) virus resulted in a generalized rickettsial and viral infection, irrespective of whether the agents were given simultaneously or by a 7 days interval apart. Both agents multiplied intensively in ticks, C.b. being detectable predominantly in cytoplasmic vacuoles and TBE virus mostly in the endoplasmic reticulum.

Animals↗
PubMedDate not supplied

[Changes in the host-dependent characteristics of the tick-borne encephalitis virus during its adaptation to ticks and its readaptation to white mice].

Features of multiplication in pig embryo kidney (PEK) cells of a variant of tick-borne encephalitis (TBE) virus previously selected by passages in H. plumbeum ticks and changes in the properties of the variant upon its repassages in white mouse brains were studied. The tick-adapted TBE variant differed from the original strain in the following characteristics: a lower yield of infectious virus and physical virus particles, altered time-course of infectious virus release from the cell, the lack of virions moving towards cathode in rocket immunoelectrophoresis (RIEP), reduced hemagglutinating activity of the virus, small plaque size in PEK culture, reduced level of virus replication in white mouse brain at a high cytopathic activity of the virus, and low synthesis of virus particles moving towards anode in RIEP. The acquired characteristics were stable at the level of 3 passages in white mice. In the course of further readaptation to these animals the virus recovered its capacity for synthesis of "cathode" virions in PEK cell culture, differing from the original strain by a higher level of virus reproduction in mammalian cells, altered electrophoretic mobility of the structural virion protein V1, and plaque size.

Adaptation, Physiological↗
PubMedDate not supplied

[Sexual transmission of the tick-borne encephalitis virus in ixodid ticks (Ixodidae)].

Sexual transmission of tick-borne encephalitis virus from infected ixodid males to noninfected females is shown: in Ixodes persulcatus in 50% (6 of 12) and in Hyalomma anatolicum in 6.2% (1 of 16). The sexual transmission of tick-borne encephalitis virus is shown to provide a transmissible transfer of the virus into eggs in ixodid ticks. Electron microscope studies of the sexual system of ixodid males infected with the virus have revealed numerous morphologically mature virus particles in lumens of endoplasmic reticulum, in vacuoles of Golgi complex of spermatocytes and in association with tubular elements of spermatids.

Animals↗
PubMed1995

Immunocytochemical mapping of FMRFamide-like peptides in the argasid tick Ornithodoros parkeri and the ixodid tick Dermacentor variabilis.

FMRFamide-like immunoreactivity was studied in the argasid tick Ornithodoros parkeri and the ixodid tick Dermacentor variabilis using immunocytochemistry based on the peroxidase-antiperoxidase method. FMRFamide-like immunoreactive cells are widely distributed in various regions of the tick synganglion including protocerebral, cheliceral, stomodeal, palpal, pedal I-IV, and opisthosomal regions in both species. However, there is one layer of immunoreactive cells located on the dorsal surface of the postoesophageal part of the synganglion that is found only in D. variabilis. Besides the immunoreactivity within the cell body and its axons, the neuropile and the neural lamella (the extracellular sheath of the synganglion) are rich in immunoreactive materials. Some coxal muscles are innervated by the FMRFamide-like immunoreactive processes of the nerve from the pedal ganglion.

Animals↗
PubMed2006

Risk assessment and prediction of Ixodes ricinus tick questing activity and human tick-borne encephalitis infection in space and time in the Czech Republic.

Present risk assessment and prediction of future risk of humans exposed to Ixodes (I.) ricinus tick attacks and, consequently, to tick-borne encephalitis (TBE) virus infection as one of the basic preconditions for successful TBE prevention has been intensively studied in the Czech Republic. An atlas of TBE in the Czech Republic containing predictive maps of I. ricinus high-incidence habitats and TBE risk sites identified by satellite data (Landsat 5 TM with spatial resolution 30 m) at a scale of 1:200,000 over a territory of 52,000 km(2) and maps of human TBE case distribution (1971-2000) has been prepared using remote sensing and geographical information systems technologies. The influence of climate changes on a forest ecosystem inhabited by I. ricinus has been studied in the southern region of the Czech Republic. The analysis of long-term series (1931-2000) of climatologic and phenological characteristics has been carried out. The results are compared with the long-term series of TBE incidence. The influence of weather condition on day-to-day changes of I. ricinus host-seeking activities was studied in 2001-2004. Field observations were realized in the south-eastern periphery of Prague where the experimental plots for tick monitoring were established in a relevant type of forest growth (Querceto-carpinetum). I. ricinus activities were investigated by the flagging method on three plots (200 m(2) each) in weekly intervals (March to November) during 2001-2004. The instruments for micrometeorological observations were installed between the experimental plots. Macrometeorological data were used from the nearby Czech Hydrometeorological Institute first class meteorological observatory. Simple and multiple linear regression and quadratic regression were used to test the relation between weather modification and I. ricinus host-seeking activity. Two preliminary most suitable 'models' are demonstrated.

Animals↗
PubMed2002

Vaccination of cattle with Anaplasma marginale derived from tick cell culture and bovine erythrocytes followed by challenge-exposure with infected ticks.

Anaplasmosis, a hemolytic disease of cattle caused by the tick-borne pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae) has been controlled using killed vaccines made with antigen harvested from infected bovine erythrocytes. We recently developed a cell culture system for propagation of A. marginale in a continuous tick cell line. In this study, we performed a cattle trial to compare the bovine response to vaccination with A. marginale harvested from tick cell culture or bovine erythrocytes. All immunized and control cattle were then challenge-exposed by allowing male Dermacentor variabilis infected with A. marginale to feed and transmit the pathogen. Nine yearling cattle (three per group) were used for this study and were immunized with cell culture-derived A. marginale, erythrocyte-derived A. marginale or received adjuvant only to serve as controls. Each vaccine dose contained approximately 2 x 10(10) A. marginale and three immunizations were administered at weeks 1, 4 and 6. At week 8, cattle were challenge-exposed by allowing 60 D. variabilis male that were infected with A. marginale as adults to feed on the cattle. Antibody responses of cattle against major surface proteins (MSP) 1a, 1b and 5, as determined by ELISAs, peaked 2 weeks after the last immunization. Cattle immunized with infected IDE8 cell-derived antigens had a preferential recognition for MSP1b while cattle immunized with erythrocyte-derived antigens had a preferential recognition for MSP1a. Protection efficacy was evaluated using the percent infected erythrocytes (PPE), the packed cell volume (PCV), and the prepatent period. A. marginale-immunized cattle showed lower PPE and higher PCV values when compared to control animals and did not display clinical anaplasmosis. The cell culture-derived A. marginale shows promise for use as antigen in development of a new killed vaccine for anaplasmosis.

Anaplasma↗
PubMed1996

Cytokine production by lymph node cells from mice infested with Ixodes ricinus ticks and the effect of tick salivary gland extracts on IL-2 production.

In BALB/c mice repeatedly infested with nymphal Ixodes ricinus ticks, lymphocytes from axillary and brachial lymph nodes which drain the tick attachment site produced significant levels of IL-2, TNF-alpha and GM-CSF when stimulated in vitro with Con A or anti-CD3 antibodies. Cytokine production by cells from lymph nodes of the opposite flank was equivalent to that of cells from uninfested mice. Nine days after the first infestation and IL-2, GM-CSF were produced primarily by the CD4+ T cells, while some other cell types contributed also to the TNF-alpha production. In mice repeatedly infested, a gradual increase of lymph node cell production of IL-2 was observed. The IL-2 levels regularly increased from the first to the third infestation compared to TNF-alpha levels which gradually decreased. The in vitro production of GM-CSF was not affected by successive infestations. Spleen lymphocytes from naive mice produced higher levels of IL-2 than lymphocytes from axillary and brachial lymph nodes. Both tick salivary gland extracts and D-mannose inhibited IL-2 production by these lymphocytes.

Animals↗
PubMed2000

Decorin-binding protein A (DbpA) of Borrelia burgdorferi is not protective when immunized mice are challenged via tick infestation and correlates with the lack of DbpA expression by B. burgdorferi in ticks.

Previous studies showed that decorin-binding protein A (DbpA) of Borrelia burgdorferi was a protective immunogen in the murine model of Lyme borreliosis when mice were challenged (needle inoculated) intradermally with in vitro-cultivated spirochetes. In the present study, DbpA-immunized C3H/HeJ mice were not protected from infection when infested with Ixodes scapularis nymphs harboring virulent B. burgdorferi 297. This lack of protection correlated with the failure to detect DbpA on B. burgdorferi in ticks, suggesting that DbpA is not available as a target for bactericidal antibodies in serum when B. burgdorferi-infected ticks take their blood meal from an immunized host. The failure of DbpA immunization to protect tick-challenged mice contradicts the results of earlier needle inoculation vaccination experiments and suggests that DbpA may not be suitable as a Lyme disease vaccine.

Adhesins, Bacterial↗
PubMed2006

Functional analysis of the tick-borne encephalitis virus cyclization elements indicates major differences between mosquito-borne and tick-borne flaviviruses.

The linear, positive-stranded RNA genome of flaviviruses is thought to adopt a circularized conformation via interactions of short complementary sequence elements located within its terminal regions. This process of RNA cyclization is a crucial precondition for RNA replication. In the case of mosquito-borne flaviviruses, highly conserved cyclization sequences (CS) have been identified, and their functionality has been experimentally confirmed. Here, we provide an experimental identification of CS elements of tick-borne encephalitis virus (TBEV). These elements, termed 5'-CS-A and 3'-CS-A, are conserved among various tick-borne flaviviruses, but they are unrelated to the mosquito-borne CS elements and are located at different genomic positions. The 5'-CS-A element is situated upstream rather than downstream of the AUG start codon and, in contrast to mosquito-borne flaviviruses, it was found that the entire protein C coding region is not essential for TBEV replication. The complementary 3'-CS-A element is located within the bottom stem rather than upstream of the characteristic 3'-terminal stem-loop structure, implying that this part of the proposed structure cannot be formed when the genome is in its circularized conformation. Finally, we demonstrate that the CS-A elements can also mediate their function when the 5'-CS-A element is moved from its natural position to one corresponding to the mosquito-borne CS. The recognition of essential RNA elements and their differences between mosquito-borne and tick-borne flaviviruses has practical implications for the design of replicons in vaccine and vector development.

Animals↗
PubMed1978

Distribution and prevalence of spotted fever group rickettsiae in ticks from South Carolina, with an epidemiological survey of persons bitten by infected ticks.

Live ticks removed from human hosts were tested for the presence of spotted fever group rickettsiae from 1974 through 1976. Spotted fever group rickettsiae were detected in Dermacentor variabilis, Amblyomma americanum, Amblyomma maculatum, and Ixodes scapularis. Persons from whom positive ticks were removed in 1974 and 1975 were questioned about ensuing illness. Eleven of 51 persons from whom rickettsia-positive D. variabilis were removed reported some unexplained combination of symptoms compatible with Rocky Mountain spotted fever. Persons with positive ticks other than D. variabilis reported no illness in the 2 weeks following exposure. D. variabilis from the Coastal Plain of South Carolina have a higher percentage of infection than those from the Piedmont region. Conversely, most reported human cases of spotted fever are from the Piedmont.

Arachnid Vectors↗
PubMed1999

Tick-borne rickettiosis in Guadeloupe, the French West Indies: isolation of Rickettsia africae from Amblyomma variegatum ticks and serosurvey in humans, cattle, and goats.

Twenty-seven rickettsiae were isolated and/or detected from 100 Amblyomma variegatum ticks collected on Guadeloupe in the French West Indies. In this study, the polymerase chain reaction procedure appeared to be more sensitive in detecting rickettsiae in ticks than the shell-vial technique. Sequencing a portion of the outer membrane protein A-encoding gene showed that these rickettsiae appeared to be identical to Rickettsia africae, a member of the spotted fever group rickettsiae recently described as an agent of African tick-bite fever occurring in sub-Sahelian Africa. A high seroprevalence of antibodies to R. africae was demonstrated among mammals, particularly humans, cattle, and goats. These results and a recently reported case of an infection due to R. africae on Guadeloupe demonstrate that R. africae is present on this island. Although this disease has been underdiagnosed there, it may be frequent and may exist on other Caribbean islands where A. variegatum has propagated dramatically over recent years.

Adolescent↗
PubMedDate not supplied

[Genetic identification of rickettsiae of the tick-borne spotted fever group, isolated in the foci of tick-borne rickettsiosis].

A total of 25 rickettsial cultures of the tick-borne spotted fever (TBSF) group from the collection of the Research Institute of Infections in Omsk, isolated from different sources in the territory of the Russian Federation (from the Urals to the Far East) during the period of 1954-2001) were studied by the methods of genetic analysis. The fragments of the gene coding the outer-membrane protein of 190 kD (ompA) and synthetase citrate (gltA) of the rickettsiae under the study were sequenced. 23 isolates were identified as R. sibirica, among them 3 isolates obtained from patients, 16 isolates obtained from Dermacentor ticks, 2 isolates from Haemaphysalis concinna and 2--from Ixodes persulcatus. The strain Primorye 32/84, isolated from D. silvarum ticks in the Far East and earlier identified as S. sibirica by the results of the PCR-RFLP analysis proved to be a genovariant Rickettsia spBJ-90, i.e. close to this species. Strain Karpunino 19/69, isolated in the Kurgan region, was identified as R. slovaca. The results obtained extended our notions of the spectrum of rickettsiae group TBSF in Russia as well as their vectors.

Animals↗
PubMed1997

[Detection of north-Asia tick-borne spotted fever in ticks and rodents along the Heilongjiang river-side by restriction fragment length polymorphism of PCR products].

In order to elucidate the natural foci of North-Asia tick-borne spotted fever along the bank of Heilongjiang river, we used PCR/RFLP to detect spotted fever group rickettsiae in ticks and rodents. The results showed that the wild samples of Dermacentor silvarum, Haemaphysalis concinna and Apodemus agrarius, Microtus fortis, Clethrionomys rufocanus and Ondatra zibethica were all positive with amplification, but typhus rickettsiae, tsutsugamushi fever rickettsiae and Q fever rickettsiae were all negative. Futher RFLP analysis of amplified products with PstI and Rsal demonstrated that their restriction endonuclease profiles were identical to Rickettsia sibirica, but were different from the other prototype strains of SFG rickettsiae, suggesting the possible existance of natural foci of North-Asia tick borne spotted fever in these areas.

Animals↗
PubMed2005

The Golden Agers and Tick-borne encephalitis. Conference report and position paper of the International Scientific Working Group on Tick-borne encephalitis.

The 7th meeting of the ISW TBE had the main topic "Tick-borne encephalitis in the Golden Agers". Data from 14 European countries were presented about incidence and clinical course of Tick borne encephalitis (TBE) in general and especially in the population over 50 years of age. With age immunity is impaired quantitatively and qualitatively, the reactions to vaccinations are generally slower, antibody titres reach lower values and decrease earlier. The incidence of the disease is increasing with age, also the clinical course is more severe, they suffer significantly more sequelae, need a longer rehabilitation and have a higher case fatality. Vaccination as the only efficient protection is needed in endemic areas, considering that mobility has increased very much. For the age group over 50 years regular booster vaccinations according to the recommended vaccination intervals or even shorter intervals are most important.

Age Factors↗