| cytological, cytochemical and immuno-fluorescence studies with dugbe virus - a new nigerian tick-borne virus. | dugbe virus, a new tick-borne arbovirus from nigeria, was propagated in continuous porcine kidney (ps) cells, and the cytopathology studied by various staining techniques such as may-grunwald-giemsa, methyl-green pyronine, feulgen, and immuno-fluorescence. the gross cytopathology was slight and infected cells continued to undergo normal mitotic divisions. the outstanding cytopathologic feature was the presence of large basophilic intracytoplasmic inclusion bodies, which were pyroninophilic and f ... | 1975 | 46127 |
| isolation of dhori virus from hyalomma marginatum ticks in portugal. | an agent pathogenic for mice was isolated from hyalomma m. marginatum ticks collected from cattle in southern portugal. serologically, the agent was indistinguishable from dhori virus, an antigenically ungrouped virus isolated in india. | 1979 | 85611 |
| crimean-congo hemorrhagic fever, thogoto, dugbe, and jos viruses isolated from ixodid ticks in ethiopia. | from 1974 through 1976, u.s. naval medical research unit no. 5 isolated 25 strain of tick-borne virus in infant mice from 410 pools containing over 6,000 ticks, and one strain from a bird and one strain from a rodent collected in central and southern ethiopia. of these, 17 were identified as known viruses previously found in west central and east africa. there were 8 strains of jos virus from amblyomma ticks; 7 strains of dugbe virus from a bird, a rodent and from ticks; 1 strains of crimean-con ... | 1978 | 98066 |
| biophysical and biological studies on jos virus (a new tick-borne virus isolated from nigeria). | jos virus possessed no haemagglutinating property within ph range 6.0--6.6 at room temperature and 37 degrees c. haemagglutination-inhibition tests with jos virus immune mouse ascitic fluid against other arbovirus antigens further confirmed the lack of serological relationships with any of the major arbovirus groups. serum neutralisation tests showed that nonspecific neuralising inhibitors of jos virus were absent in normal sera. jos virus is highly thermolabile; a sharp reduction of virus infec ... | 1978 | 108941 |
| tick-borne viruses associated with seabirds in north america and related islands. | about 18 tickborne viruses associated with seabirds are known from canada, mexico, the antilles, and the united states, including its oceanic islands. antigenic groups to which these viruses belong are hughes, b, sakhalin, uukuniemi, kemerovo, nyamani and quaranfil. members of the last two groups are known in the western hemisphere only from central pacific islands and may reflect intrusion of elements of the australian region. in the areas under discussion, antibody surveys have been minimal, b ... | 1975 | 173938 |
| tick-borne viruses in finland. | ixodes ricinus is the only one of six tick species reported from finland found to carry viruses. it transmits tick-borne encephalitis and uukuniemi viruses, and transmission of a kemerovo group virus is suggested by antibody findings. tick-borne encephalitis is common only in the sw-archipelago; it is also found near the se-boarder but is very rare elsewhere. in contrast, uukuniemi virus is common throughout the distribution area of i. ricinus, being commoner on the mainland than in the archipel ... | 1975 | 173939 |
| the susceptibility of isolated guts from various species of mosquito to some arboviruses. | isolated guts cultured in vitro from aedes aeaegypti and ae. togoi were more susceptible to infection by sin, sf, chik and wn viruses than tissue similarly cultured from anopheles gambiae and an. stephensi. langat tp 64, a tick-borne virus, failed to infect any of the cultured mosquito tissues. | 1976 | 178280 |
| experimental mixed infection with two tick-borne viruses and interferon-mediated interference. | tick-borne encephalitis virus (tev), a flavivirus, and lipovník virus (lv), a member of the kemerovo group and complex and possible member of the rioviridae, were used to infect chick embryo cell (cec) cultures. lv reproduction was inhibited by preinfection with tev, mainly in aged cultures. in young cec cultures, tev production was stimulated slightly and interferon was sometimes depressed by this superinfection; on the contrary, in aged cultures the superinfecting lv stimulated interferon also ... | 1975 | 235191 |
| serological studies on dhori virus. | | 1977 | 608739 |
| [surgey of tick-borne arboviruses in the central african republic (1973-1974). isolation of dugbe, chf/congo, jos and bhanja viruses]. | as a complement of the study of the epidemiology of the arboviruses in central africa a survey of tick borne viruses has been done, in the central african republic, from december 1972 to june 1974; 15.103 ticks were collected, mainly from cattle at the slaughterhouses. they include: 10.085 ambylomma variegatum, 4.113 boophilus, 542 rhipicephalus and 363 hyalomma. from 892 monospecific pools inoculated into baby mice, 98 isolates of virus were obtained. among the 57 isolates which have been fully ... | 1976 | 1036474 |
| [isolation of thogoto virus from amblyomma and boophilus ticks in central africa]. | a survey has been carried out in the cameroons and the central african republic about the role of the ticks in the ecology of arboviruses in central africa. attempts for virus isolation were made for 12,678 amblyomma variegatum, 3,276 boophilus decoloratus and 1,769 boophilus annulatus, by inoculation into suckling mice. from 968 pools which were inoculated, 20 yielded isolates which were identified to thogoto virus. considering previously published results concerning tick-borne virus isolations ... | 1976 | 1037382 |
| tick-borne viruses in norway. | the purpose of the investigation was to chart the existence and extent of arboviruses in norway and provide information on their possible significance. virus isolations have been attempted from ticks (i. ricinus, i. trianguliceps, i. uriae) and host animal blood from selected locations. serological screenings have been performed with bird, small mammal, cattle and human blood. five virus strians have been identified to date. three of them are related to uukuniemi virus group. two identical strai ... | 1975 | 1207194 |
| cellular control of the tick-borne virus antigen production in persistently infected cell culture. | the influence of inhibition or stimulation of cellular dna synthesis on tick-borne virus antigen production in persistently infected cell culture was studied. either mitomycin c or cytosine-arabinoside caused cessation of antigen-containing cell number increase. stimulation of cellular dna synthesis by growth medium change increased the level of antigen-containing cells. when hep-2-sof culture was synchronized, a correlation was observed between the entrance of cells into dna synthesis phase and ... | 1976 | 1253898 |
| identification of viral structural polypeptides of thogoto virus (a tick-borne orthomyxo-like virus) and functions associated with the glycoprotein. | thogoto (tho) virus is a tick-borne virus which shares morphological and genetic features with members of the orthomyxoviridae family although the viral glycoprotein appears to be related to gp64 of baculoviruses. characterization of tho virus was undertaken to clarify its taxonomic position. purified virus preparations contained at least six virus-encoded polypeptides with apparent m(r) values ranging from 29k to 92k. a 75k polypeptide was identified as an envelope-associated glycoprotein by tr ... | 1992 | 1279100 |
| heterologous resistance to superinfection by louping ill virus persistently infected cell cultures. | louping ill virus, a tick-borne arbovirus readily established a persistent infection in porcine kidney (ps) cells after initially inducing minor cytopathic changes. nucleotide sequence analysis of the envelope glycoprotein of the viral rna recovered from the persistently infected cells showed no changes as compared with the virus used to establish persistent infections. more than 80 per cent of the cells contained virus specific antigen when analysed by indirect immunofluorescence microscopy. th ... | 1992 | 1322654 |
| nucleotide sequence of the envelope glycoprotein of negishi virus shows very close homology to louping ill virus. | negishi virus, a member of the family flaviviridae, was originally isolated in japan, during an outbreak of japanese encephalitis. antigenically, however, negishi virus resembles the tick-borne rather than the mosquito-borne flaviviruses. monoclonal antibodies that bind louping ill virus showed a close antigenic relationship between louping ill and negishi virus. the genes encoding the envelope glycoprotein of negishi virus (strain 3248/49/p10) and louping ill virus (strain sb526) were cloned an ... | 1992 | 1326816 |
| envelope protein sequences of dengue virus isolates th-36 and th-sman, and identification of a type-specific genetic marker for dengue and tick-borne flaviviruses. | complementary dnas were synthesized from the envelope protein genes of two isolates of dengue virus (th-36 and th-sman, previously suggested as possible dengue virus type 5 and dengue virus type 6 respectively) and amplified by the polymerase chain reaction using sense and antisense primers designed from conserved dengue virus gene sequences. the amplified cdna clones were sequenced in both directions by double-stranded dideoxynucleotide sequencing. alignment with published dengue virus sequence ... | 1992 | 1339466 |
| dhori virus induced lesions in mice. | dhori and thogoto viruses are till now the only recognized tick-borne orthomyxoviruses. like thogoto virus, also dhori is highly hepatotropic for laboratory mice; the lesions in several organs resemble those described for influenza virus. | 1990 | 1983186 |
| evolutionary relatedness of the predicted gene product of rna segment 2 of the tick-borne dhori virus and the pb1 polymerase gene of influenza viruses. | the complete nucleotide sequence of the second largest rna segment of dhori/india/1313/61 virus was determined and the deduced amino acid sequence was compared with the polymerase (p) proteins of influenza a, b, and c viruses. rna segment 2 (2224 nucleotides) of dhori virus contains a single long open reading frame that can encode a 716-amino acid polypeptide (81.3 kda). the predicted polypeptide shares between 27 and 31% sequence identities with the pb1 polypeptides of influenza a, b, and c vir ... | 1991 | 2024457 |
| attenuation of virulence of flaviviruses following passage in hela cells. | the ability of passage in hela cells to attenuate flaviviruses was investigated for three different strains of the mosquito-borne west nile (wn) virus and two tick-borne viruses, louping-ill and langat. one strain of wn virus, sarawak, was attenuated 4000-fold for adult mice by intraperitoneal or intranasal challenge after six hela passages. the hela-passaged virus was also found to be antigenically different and temperature-sensitive in its growth characteristics compared with the parent. after ... | 1990 | 2155996 |
| nucleotide sequence of the tick-borne, orthomyxo-like dhori/indian/1313/61 virus envelope gene. | the complete nucleotide sequence of the fourth largest segment of single-stranded rna of the tick-borne, orthomyxo-like dhori/indian/1313/61 virus was determined by using cloned cdna derived from infected cell mrna. the fourth rna contains 1586 nucleotides and can code for a protein of 521 amino acids with a molecular weight of 58,675 da. the predicted polypeptide possesses an amino-terminal hydrophobic region that may function as a signal sequence to initiate translocation across the endoplasmi ... | 1990 | 2309437 |
| the effect of host resistance to tick infestation on the transmission of thogoto virus by ticks. | tick-borne virus transmission was examined using guinea-pigs and hamsters previously infested with ticks. guinea-pigs developed immunity to rhipicephalus appendiculatus after a single exposure to the ticks. nymphal and adult stages that fed on resistant guinea-pigs had increased mortality during feeding, and reduced engorged weights. egg production from female ticks fed on resistant hosts fell by at least 50%. guinea-pigs maintained high levels of immunity to tick infestation for at least 210 da ... | 1990 | 2345364 |
| studies on the glycosylation of flavivirus e proteins and the role of carbohydrate in antigenic structure. | the glycosylation pattern of several flavivirus e proteins as well as the role of carbohydrate in biological functions and the antigenic structure of tick-borne encephalitis (tbe) virus were investigated by the use of specific endoglycosidases. endoglycosidase f digestion revealed the presence of a single asparagine-linked oligosaccharide side chain in tbe virus (western and far eastern subtype), louping iii virus, murray valley encephalitis virus, and rocio virus. consistent with published sequ ... | 1987 | 2441520 |
| anatomical basis of thogoto virus infection in bhk cell culture and in the ixodid tick vector, rhipicephalus appendiculatus. | infection by thogoto (tho) virus, a tick-borne virus related to the orthomyxoviruses, has been compared in vertebrate cell culture and in rhipicephalus appendiculatus ticks using infectivity titrations, immunofluorescence, and immune electron microscopy with colloidal gold markers to detect cell surface and intracellular antigens. morphogenesis of tho virus in cell culture was similar to that of influenza virus, with polymorphic virus particles budding at the plasma membrane. in the tick, tho vi ... | 1989 | 2543769 |
| the effect of virus-immune hosts on thogoto virus infection of the tick, rhipicephalus appendiculatus. | thogoto (tho) virus infections of rhipicephalus appendiculatus ticks were examined using tick hosts immune to the virus. in the first set of experiments, ticks were infected by feeding on viraemic hamsters. inter-stadial infection of tho virus was not affected when ticks ingested a virus-immune bloodmeal but there was an effect on persistence of the virus. the incidence of intra-stadial infection was reduced by at least 40% when nymphs partially fed on viraemic hamsters and completed their blood ... | 1989 | 2558460 |
| viral interference in the tick, rhipicephalus appendiculatus. i. interference to oral superinfection by thogoto virus. | interference between arboviruses in a naturally infected tick vector is reported for the first time. rhipicephalus appendiculatus nymphs were dually infected with thogoto (tho) virus, a tick-borne virus, similar to members of the family orthomyxoviridae. in the first series of experiments examining 'inter-stadial' interference, larvae were orally infected with a temperature-sensitive (ts) mutant, and after moulting the nymphs were superinfected with the wild-type (wt) virus. in the second series ... | 1989 | 2778441 |
| sequence analyses of thogoto viral rna segment 3: evidence for a distant relationship between an arbovirus and members of the orthomyxoviridae. | the genome of thogoto (tho) virus, an unclassified tick-borne virus, comprises six segments of single-stranded rna. the complete sequence of the third largest rna segment has been determined from overlapping cdna clones and by primer extension studies. segment 3 rna consists of 1865 nucleotides (approx. 6.2 x 10(5) mr). it has a large open reading frame (orf1;597 amino acids, 68.6k) in its virus-complementary sequence, confirming that the rna has a negative-sense coding strategy. a transcription ... | 1989 | 2794982 |
| a disease resembling louping-ill in sheep in the basque region of spain. | a clinical syndrome resembling louping-ill which primarily affects lambs and yearlings in the basque region of spain is described. the disease has been observed for several years during may and june after the sheep flocks have been taken to the mountain grazings where the sheep tick (ixodes ricinus) is known to occur. examination of the brain from one of the affected animals revealed histological changes indistinguishable from those caused by louping-ill virus. in addition antibody that reacted ... | 1987 | 2820110 |
| antibodies to congo-crimean haemorrhagic fever, dhori, thogoto and bhanja viruses in southern portugal. | dhori and thogoto viruses have been isolated from ticks in portugal. in this country favourable ecologic conditions exist for other tick-borne viruses such as bhanja and congo-crimean haemorrhagic fever (c-chf) viruses. a serological survey for antibodies to these 4 tick-borne viruses in 258 human and 141 goat sera was done using the plaque reduction neutralization (prn) and indirect fluorescent antibody (ifa) tests. six human sera were found with antibodies to dhori (2), thogoto (2) and c-chf ( ... | 1985 | 2864836 |
| [dhori virus--a causative agent of human disease. 5 cases of laboratory infection]. | the materials presented in the paper are first indications of the pathogenicity of dhori virus for man and prove the role of this agent in the occurrence of 5 cases of the disease in laboratory workers accidentally infected during the preparation of cultural agents. clinically, dhori infection was characterized by an acute course with marked general toxicity and a febrile period of 2 to 4 days. two out of 5 patients had changes on the part of the nervous system of the type of encephalitic reacti ... | 1987 | 3445590 |
| [hemagglutination-inhibiting antibodies against a newly isolated tick-borne virus as occurring in the healthy population of lower franconia]. | | 1970 | 4099801 |
| comparison of the virion polypeptides of group b arboviruses. | the virion polypeptides of eight group b arboviruses were compared by polyacrylamide gel coelectrophoresis. all contained three polypeptides, v-1, v-2, and v-3. the mosquito-borne viruses had electrophoretically similar small membrane polypeptides (v-1); the tick-borne viruses had a v-1 of significantly decreased mobility. | 1972 | 4144016 |
| susceptibility of rabbit kidney cell cultures to egyptian strains of tick-borne viruses. | | 1970 | 4392847 |
| jos, a new tick-borne virus from nigeria. | | 1974 | 4416978 |
| effect of route of inoculation on histopathological changes induced in mice by dugbe virus (a nigerian tick-borne virus). | | 1974 | 4479820 |
| dhori virus, a new agent isolated from hyalomma dromedarii in india. | | 1973 | 4781001 |
| the relationship between the tick-borne encephalitis virus and the ticks and mammals of the tribec mountain range. | the basic problem in the study of tick-borne virus diseases is to establish where the virus is maintained in nature. in general, this focus will be found where there are large and relatively stable populations of ticks, small rodents and insectivores. in the tribec region the principal vector of tick-borne encephalitis (tbe) is ixodes ricinus, although other species can circulate the virus under suitable conditions. the virus can persist during winter either in starving nymphs or adults or in no ... | 1967 | 5298540 |
| tick-borne viruses of west pakistan. i. isolation and general characteristics. | | 1970 | 5458946 |
| tick-borne viruses of west pakistan. 3. dera ghazi khan virus, a new agent isolated from hyalomma dromedarii ticks in the d. g. khan district of west pakistan. | | 1970 | 5460469 |
| experimental infection with tick-borne virus in clethrionomys glareolus, apodemus flavicollis, apodemus sylvaticus and mus musculus. 2. serological studies. | | 1966 | 5958662 |
| mixed infections with tick-borne viruses in a seabird colony in eire. | viruses were isolated from 2 tick species collected from the nesting areas of seabirds on great saltee island, eire. bunyaviruses of the uukuniemi serogroup were isolated from hard ticks (ixodes uriae and i. rothschildi), bunyaviruses of the hughes serogroup from soft ticks (ornithodoros maritimus), and orbiviruses of the kemerovo serogroup from i. uriae and o. maritimus. the results indicate that the bunyaviruses, but not the orbiviruses, show "tick specificity". neutralising activity against m ... | 1984 | 6421266 |
| comparison of mice and cell cultures for the isolation of tick-borne viruses. | three methods of isolating viruses from 10 tick pools were compared; none of the methods produced all 13 of the viruses isolated (7 viruses of the bunyaviridae and 6 orbiviruses). inoculation of homogenised ticks into various cell lines was the most successful, yielding 11 virus isolations. only 2 tick homogenates induced overt signs of infection following intra-cerebral inoculation of 2-day-old mice. however, when inoculated mouse brain was passaged in various cell lines, 8 of 12 isolations wer ... | 1984 | 6501535 |
| 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 morpho ... | 1984 | 6508529 |
| [arbovirus infections in tunisia: new serological survey of small wild mammals]. | sera of 103 small wild mammals (rodents, insectivora, cheiroptera) trapped at the beginning of 1980 in different areas of tunisia were studied for antibody against 15 arboviruses. in inhibition haemagglutination tests, positive reactions were found against dengue type 2 (2.2%), tahyna (18.4%), arumowot (42.7%) and sicilian sandfly fever (31%) viruses. no antibody was found for 8 tick-borne viruses. in comparison with previous sero-surveys, our results indicated a fall of west nile virus activity ... | 1983 | 6839405 |
| isolation and characterization of midway virus: a new tick-borne virus related to nyamanini. | midway virus, a new tick-borne virus isolated from two species of ornithodoros (alectorobius) ticks of the capensis group (o capensis, o denmarki), is described from midway, kure, and manana islands in the central pacific (hawaiian archipelago) and from northern honshu (japan). midway virion is enveloped, unusually large, acid and temperature sensitive, and its type of nucleic acid is rna. complement-fixation (cf) tests show a close relation of midway to nyamanini virus, which has been isolated ... | 1982 | 7153772 |
| [tick-borne viruses in tropical area (author's transl)]. | arboviruses, transmitted by ticks and pathogenic to man in tropical areas, are discussed. they are considered according to, first the faunal region in which they can be found, then the type of syndrome they cause. the greater part is of little medical importance, some are noxious but of a rare occurrence (thogoto, wanowrie, langat) or geographically restrained (kyasanur forest disease), so the crimean-congo hemorrhagic fever is the only infection to show a notorius importance. as severe in the t ... | 1980 | 7442510 |
| crimean congo-haemorrhagic fever treated with oral ribavirin. | crimean-congo haemorrhagic fever (cchf) is an often-lethal haemorrhagic fever caused by a tick-borne virus. there are no published data on ribavirin treatment of cchf-infected patients, despite established in-vitro and in-vivo sensitivity. we report three health workers--two surgeons and a hospital worker--infected with cchf virus in pakistan who were treated with oral ribavirin 4 g/day for four days, then 2.4 g/day for six days. intravenous ribavirin was unavailable. all three patients were sev ... | 1995 | 7637481 |
| mx1 but not mxa confers resistance against tick-borne dhori virus in mice. | the interferon-induced nuclear mx1 protein is responsible for innate resistance of mice to influenza virus. it has been unclear why mice are equipped with a powerful and specific defense mechanism against influenza viruses for which they are not natural hosts. here, we show that dhori virus, an influenza-like virus transmitted by ticks and known to infect small mammals, is sensitive to the mx1 resistance mechanism. influenza virus-susceptible balb/c and c57bl/6 mice (lacking a functional mx1 gen ... | 1995 | 7645224 |
| tunis virus: a new phlebovirus from argas reflexus hermanni ticks in tunisia. | a new phlebovirus provisionally named tunis virus has been isolated from argas reflexus hermanni ticks parasitizing domestic pigeons. it is the first isolation of an arbovirus from tunisia and the fourth tick-borne virus to be isolated from the moghreb following soldado, essaouira and kala iris in morocco. the pathogenic potential of this virus is briefly discussed according to the behaviour of its vector and previous serosurveys in the country. | 1994 | 7726003 |
| human mxa protein inhibits tick-borne thogoto virus but not dhori virus. | thogoto and dhori viruses are tick-borne orthomyxoviruses infecting humans and livestock in africa, asia, and europe. here, we show that human mxa protein is an efficient inhibitor of thogoto virus but is inactive against dhori virus. when expressed in the cytoplasm of stably transfected cell lines, mxa protein interfered with the accumulation of thogoto viral rna and proteins. likewise, mxa(r645), a mutant mxa protein known to be active against influenza virus but inactive against vesicular sto ... | 1995 | 7745744 |
| salivary gland extracts of partially fed dermacentor reticulatus ticks decrease natural killer cell activity in vitro. | the salivary glands and saliva of ticks (arachnida, acari, ixodida) play a vital role in blood feeding, including manipulation of the host's immune response to tick infestation. furthermore, a diverse number of tick-borne pathogens are transmitted to vertebrate hosts via tick saliva. a factor synthesized in the salivary glands of feeding ticks potentiates the transmission of certain tick-borne viruses. we show that salivary gland extracts (sge) derived from dermacentor reticulatus female ticks f ... | 1994 | 8045588 |
| persistence and transmission of tick-borne viruses: ixodes ricinus and louping-ill virus in red grouse populations. | the population dynamics of tick-borne disease agents and in particular the mechanisms which influence their persistence are examined with reference to the flavivirus that causes louping-ill in red grouse and sheep. pockets of infection cause heavy mortality and the infection probably persists as a consequence of immigration of susceptible hosts. seroprevalence is positively associated with temporal variations in vectors per host, although variation between areas is associated with the abundance ... | 1995 | 8632924 |
| importance of localized skin infection in tick-borne encephalitis virus transmission. | arboviruses are transmitted to vertebrates by the "bite" of infected arthropods. events at the site of virus deposition are largely unknown despite increasing evidence that blood-sucking arthropods immunomodulate their skin site of feeding. this question is particularly relevant for ixodid ticks that feed for several days. to examine events under conditions mimicking tick-borne encephalitis (tbe) virus transmission in nature (i.e., infected and uninfected ixodes ricinus ticks feeding on the same ... | 1996 | 8638401 |
| investigation of tick-borne viruses as pathogens of humans in south africa and evidence of dugbe virus infection in a patient with prolonged thrombocytopenia. | in the course of investigating suspected cases of viral haemorrhagic fever in south africa patients were encountered who had been bitten by ticks, but who lacked evidence of infection with crimean-congo haemorrhagic fever (cchf) virus or non-viral tick-borne agents. cattle sera were tested by enzyme-linked immunoassay to determine whether tick-borne viruses other than cchf occur in the country. the prevalence of antibody in cattle sera was 905/2116 (42.8%) for cchf virus, 70/1358 (5.2%) for dugb ... | 1996 | 8666081 |
| [tick-borne encephalitis in central and eastern europe]. | the tick-borne encephalitis virus, a major arbovirus, is endemic in central and eastern europe. since the first case of tick-borne encephalitis observed in alsace in 1968, there have been approximately 30 cases reported in eastern france. the tick ixodes persulcatus (and the western subtype i. ricinus) is both the main reservoir and vector of the disease. early clinical signs of infection are followed by a second phase complicated with meningoencephalitis. the geographical distribution of the di ... | 1996 | 8685190 |
| thogoto and dhori virus replication is blocked by inhibitors of cellular polymerase ii activity but does not cause shutoff of host cell protein synthesis. | tick-transmitted thogoto and dhori viruses share structural and genetic properties with the influenza viruses. here, we compare different steps of their replication cycle in mammalian cells in comparison with influenza a virus. viral antigens of both viruses accumulated in the nuclei of infected cells, suggesting a nuclear phase of viral replication. furthermore, as observed with influenza viruses, transcription of thogoto and dhori viruses was inhibited by alpha-amanitin and actinomycin d, sugg ... | 1996 | 8856036 |
| nucleoprotein viral rna and mrna of thogoto virus: a novel "cap-stealing" mechanism in tick-borne orthomyxoviruses? | tick-borne thogoto virus (thov) represents the prototype virus of a new genus in the orthomyxoviridae family. its genome consists of six segments of negative-sense, single-stranded rna. we have cloned and sequenced the fifth genomic segment, which codes for the viral nucleoprotein (np). the deduced amino acid sequence shows 43% similarity to the np of dhori virus, a related tick-transmitted orthomyxovirus, and about 14% sequence similarity to those of the influenza viruses. to reveal the mechani ... | 1996 | 8970956 |
| complete sequence of two tick-borne flaviviruses isolated from siberia and the uk: analysis and significance of the 5' and 3'-utrs. | the complete nucleotide sequence of two tick-transmitted flaviviruses, vasilchenko (vs) from siberia and louping ill (li) from the uk, have been determined. the genomes were respectively, 10928 and 10871 nucleotides (nt) in length. the coding strategy and functional protein sequence motifs of tick-borne flaviviruses are presented in both vs and li viruses. the phylogenies based on maximum likelihood, maximum parsimony and distance analysis of the polyproteins, identified vs virus as a member of ... | 1997 | 9178494 |
| the fourth genus in the orthomyxoviridae: sequence analyses of two thogoto virus polymerase proteins and comparison with influenza viruses. | the tick-borne thogoto virus (thov) is the type species of a newly recognized fourth genus, thogotovirus, in the family orthomyxoviridae. because of the distant relationship of thov with the influenza viruses, determination of its genomic information can potentially be used to identify important domains in influenza virus proteins. we have determined the complete nucleotide sequence of the second longest rna segment of thov. the molecule comprises 2212 nucleotides with a single large open readin ... | 1997 | 9282786 |
| mx1 sensitivity: batken virus is an orthomyxovirus closely related to dhori virus. | batken virus, isolated from mosquitoes and ticks, was tentatively classified as a member of the family bunyaviridae. here we show that batken virus is inhibited by the interferon-induced mx1 protein of mice which selectively blocks the growth of orthomyxoviruses, including thogoto and dhori viruses. furthermore, we show that batken virus multiplication is characterized by accumulation of viral proteins in the nucleus and by budding of viral particles from the cell surface. serological cross-reac ... | 1997 | 9349464 |
| tick virus diseases of sheep and goats. | tick-borne viruses affecting sheep and goats can be be locally important diseases. viruses of the tick-borne encephalitis complex occur across europe to north-east asia and are the cause of significant losses in small ruminant production. thogoto virus which can be transmitted by ixodid ticks has been associated with abortion storms in sheep, it may contribute to the large proportion of abortions which are due to unknown causes. nairobi sheep disease is the most pathogenic virus disease known fo ... | 1997 | 9530690 |
| suppressive effect of ixodes ricinus salivary gland extract on mechanisms of natural immunity in vitro. | tick saliva has been shown to contain a variety of pharmacologically active molecules, including those with immunosuppressive activities. there is increasing evidence that the nonspecific suppression of host immunity by tick saliva is exploited by tick-borne pathogens, e.g. the saliva-activated transmission (sat) of some tick-borne viruses. we have demonstrated the suppressive effect of the salivary gland extract (sge) derived from partially fed (five days) ixodes ricinus females on important me ... | 1998 | 9618727 |
| mx1-based resistance to thogoto virus in a2g mice is bypassed in tick-mediated virus delivery. | the interferon-induced mouse mx1 protein has intrinsic antiviral activity against orthomyxoviruses, including thogoto virus. thus, mx1(+) a2g mice are apparently resistant to infection following needle- or tick-borne virus challenge. however, tick-borne challenge and, to a lesser degree, injection of virus mixed with tick salivary gland extract resulted in virus transmission to uninfected ticks feeding on the a2g mice. the data indicate that immunomodulatory components in tick saliva can overcom ... | 1998 | 9733885 |
| persistence of tick-borne virus in the presence of multiple host species: tick reservoirs and parasite mediated competition. | tick-borne viruses in tropical and temperate parts of the world have a significant impact on human, livestock and wildlife hosts both directly, through mortality/morbidity, and economically. since the ticks have multiple life stages and can utilize a large range of host species our understanding of the dynamics of these infections is often not clear. in this paper we consider the impact of a population which is a tick host but non-viraemic on one which is both a tick host and viraemic. we presen ... | 1999 | 10479543 |
| intra-stadial tick-borne thogoto virus (orthomyxoviridae) transmission: accelerated arbovirus transmission triggered by host death. | haematophagous insect vectors of arthropod-borne viruses (arboviruses) feed repeatedly. consequently, they can transmit arboviruses to more than one host during the same developmental stage (intra-stadial transmission). by contrast, ixodid ticks generally feed only once at each parasitic stage (larva, nymph, and adult) and hence they have only one opportunity for tickborne virus transmission per stadium (inter-stadial transmission). under natural conditions, tick-infested hosts may die (from dis ... | 2001 | 11315177 |
| essential role of cyclization sequences in flavivirus rna replication. | a possible role in rna replication for interactions between conserved complementary (cyclization) sequences in the 5'- and 3'-terminal regions of flavivirus rna was previously suggested but never tested in vivo. using the m-fold program for rna secondary-structure predictions, we examined for the first time the base-pairing interactions between the covalently linked 5' genomic region (first ~160 nucleotides) and the 3' untranslated region (last ~115 nucleotides) for a range of mosquito-borne fla ... | 2001 | 11413342 |
| phylogenetic relationships of flaviviruses correlate with their epidemiology, disease association and biogeography. | phylogenetic analysis of the flavivirus genus, using either partial sequences of the non-structural 5 gene or the structural envelope gene, revealed an extensive series of clades defined by their epidemiology and disease associations. these phylogenies identified mosquito-borne, tick-borne and no-known-vector (nkv) virus clades, which could be further subdivided into clades defined by their principal vertebrate host. the mosquito-borne flaviviruses revealed two distinct epidemiological groups: ( ... | 2001 | 11457992 |
| sequence comparison and secondary structure analysis of the 3' noncoding region of flavivirus genomes reveals multiple pseudoknots. | sequences of 191 flavivirus rnas belonging to four sero-groups were used to predict the secondary structure of the 3' noncoding region (3' ncr) directly upstream of the conserved terminal hairpin. in mosquito-borne flavivirus rnas (n = 164) a characteristic structure element was identified that includes a phylogenetically well-supported pseudoknot. this element is repeated in the dengue and japanese encephalitis rnas and centers around the conserved sequences cs2 and rcs2. in yellow fever virus ... | 2001 | 11680841 |
| heterogeneity in the effect of different ixodid tick species on human natural killer cell activity. | tick saliva plays a vital role in blood-feeding, including manipulation of the host response to tick infestation. furthermore, a diverse number of tick-borne pathogens are transmitted to vertebrate hosts via tick saliva, some of which exploit the immunomodulatory activities of their vector's saliva. we report that salivary gland extracts (sge) derived from dermacentor reticulatus adult ticks induce a decrease in the natural killer (nk) activity of effector cells obtained from healthy human blood ... | 2002 | 11856443 |
| influence of nonsystemic transmission on the epidemiology of insect borne arboviruses: a case study of vesicular stomatitis epidemiology in the western united states. | nonsystemic transmission, where a pathogen is transmitted between infected and uninfected vectors without the vertebrate host becoming viremic, may provide an explanation for transmission in systems where the vertebrate hosts have been difficult to identify. this transmission pathway had been previously demonstrated for tick-borne viruses and bacteria, but the recent demonstration for simulium and vesicular stomatitis virus is the first for a blood-feeding insect. the epidemiology of vesicular s ... | 2002 | 12061433 |
| [the isolation of dhori viruses (orthomyxoviridae, thogotovirus) and crimean-congo hemorrhagic fever virus (bunyaviridae, nairovirus) from the hare (lepus europaeus) and its ticks hyalomma marginatum in the middle zone of the volga delta, astrakhan region, 2001]. | in august, 2001, in the middle zone of the delta of the volga river, the astrakhan region, during investigation of the natural foci of west nile fever and crimean--congo hemorrhagic fever (cchf), the material from the hare (lepus europaeus, pallas, 1778 (lagomorpha, leporidae) and collected from it the ticks hyalomna marginatum koch 1844, was obtained. 4 strains of dhori virus (orthomyxoviridae, thogotovirus) and 2 strains of cchf virus (bunyaviridae, nairovirus) were isolated. this is the first ... | 2002 | 12271723 |
| trophic interactions and population growth rates: describing patterns and identifying mechanisms. | while the concept of population growth rate has been of central importance in the development of the theory of population dynamics, few empirical studies consider the intrinsic growth rate in detail, let alone how it may vary within and between populations of the same species. in an attempt to link theory with data we take two approaches. first, we address the question 'what growth rate patterns does theory predict we should see in time-series?' the models make a number of predictions, which in ... | 2002 | 12396517 |
| the extent of homologous recombination in members of the genus flavivirus. | the family flaviviridae includes important human pathogens, such as dengue (den) virus, yellow fever (yf) virus and hepatitis c virus, many of which have emerged or re-emerged in recent years. until recently, flavivirus evolution was thought to proceed in a clonal manner, with diversity generated mainly through the accumulation of mutational changes. however, this assumption has now been shown to be invalid, with homologous recombination demonstrated in all three genera of the flaviviridae: sinc ... | 2003 | 12560576 |
| detection of immunoglobulin g to crimean-congo hemorrhagic fever virus in sheep sera by recombinant nucleoprotein-based enzyme-linked immunosorbent and immunofluorescence assays. | crimean-congo hemorrhagic fever virus is a tick-borne virus that causes severe hemorrhagic symptoms with an up to 50% mortality rate in humans. wild and domestic animals, such as sheep, cattle and goats, are the reservoirs. the recombinant nucleoprotein-based crimean-congo hemorrhagic fever virus antibody detection systems for sheep sera were developed by enzyme-linked immunosorbent assay (elisa) and an indirect immunofluorescence assay techniques. the samples used for evaluation were 80 sera co ... | 2003 | 12565161 |
| tick-borne viruses. a review of an arthropod-borne virus problem of growing importance in the tropics. | more than 150 arthropod-borne viruses are now recognized, and over 50 of these are known to produce human infections and disease. among these viruses are those of the tick-borne russian spring-summer complex, which is etiologically involved in a wide variety of human diseases of varying severity. the eight antigenically different members of this complex so far known are russian spring-summer encephalitis, louping-ill, central european encephalitis, omsk haemorrhagic fever, kyasanur forest diseas ... | 1963 | 14043753 |
| further studies on antigenic relationships among the viruses of the group b tick-borne complex. | this paper is a report on further studies of the antigenic relationships among viruses of the group b tick-borne complex, carried out by the haemagglutination-inhibition (hi), complement-fixation, absorption-hi and diffusion-in-gel techniques. earlier work has been extended to include powassan and negishi viruses.comparisons of a number of strains of tick-borne viruses have revealed inter-strain variation only in the case of omsk haemorrhagic fever virus, where two subtypes are distinguishable.t ... | 1964 | 14230894 |
| the role of non-viraemic transmission on the persistence and dynamics of a tick borne virus--louping ill in red grouse ( lagopus lagopus scoticus) and mountain hares ( lepus timidus). | there exist many tick borne infections that are of either economic or public health interest. mathematical models have previously been used to describe the dynamics of these infections. however it has recently come to light that there is an alternative mechanism for the transmission of these diseases that has not been considered in a modelling framework. this is transmission through ticks co-feeding on non-viraemic hosts. this paper extends a simple mathematical model to include this alternative ... | 2004 | 14745507 |
| the high genetic variation of viruses of the genus nairovirus reflects the diversity of their predominant tick hosts. | the genus nairovirus (family bunyaviridae) contains seven serogroups consisting of 34 predominantly tick-borne viruses, including several associated with severe human and livestock diseases [e.g., crimean congo hemorrhagic fever (cchf) and nairobi sheep disease (nsd), respectively]. before this report, no comparative genetic studies or molecular detection assays had been developed for this virus genus. to characterize at least one representative from each of the seven serogroups, reverse transcr ... | 2004 | 14972529 |
| a simple assay for determining antiviral activity against crimean-congo hemorrhagic fever virus. | crimean-congo hemorrhagic fever virus (cchfv) is a tick-borne virus that is emerging as a significant human pathogen in many regions of the world, including africa, asia, and europe. in this report, we describe a simple screening method for discovering new antiviral compounds directed against cchfv. antiviral activity was determined by assaying infected sw-13 cells (human adrenal gland carcinoma) for protection from cytopathic effect (cpe). by using an in vitro neutral red uptake assay, we were ... | 2004 | 15026198 |
| recombinant vp6-based enzyme-linked immunosorbent assay for detection of immunoglobulin g antibodies to eyach virus (genus coltivirus). | eyach virus (eyav) is a tick-borne virus belonging to genus coltivirus, family reoviridae. it was isolated in germany and france and has been suspected to be responsible for neurological diseases in humans. to date, there has been no relatively rapid and relatively specific serological assay for eyav. | 2004 | 15135744 |
| genetic analysis of crimean-congo hemorrhagic fever virus in iran. | crimean-congo hemorrhagic fever (cchf) is a potentially fatal disease caused by a tick-borne virus in the family bunyavridae. the disease occurs in parts of africa, asia, middle east, and eastern europe. during recent years, an increasing number of human cchf cases have been diagnosed in iran, but very little information is available on the prevalence and genetic diversity of cchfv in iran. in the present study, cchf virus (cchfv) isolates from nine iranian patients infected during 2002 were exa ... | 2004 | 15170636 |
| [tick-borne human pathogenic microorganisms found in europe and those considered nonpathogenic. part ii: bacteria, parasites and mixed infections]. | the importance of tick-borne diseases has significantly increased objectively and subjectively during the last few years. this fact was demonstrated by the description of tick-borne viruses, in particular with respect to tickborne encephalitis published in part i. here in part ii, tick-borne bacteria and parasites will be discussed as well the significance of these agents, their vectors, clinical course, diagnostics, prophylaxis, and therapy. naturally, lyme borreliosis, one of the most importan ... | 2004 | 15205761 |
| [tick-borne human pathogenic microorganisms found in europe and those considered nonpathogenic. part i: ticks and viruses]. | 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. a ... | 2004 | 15205783 |
| solution structure and structural dynamics of envelope protein domain iii of mosquito- and tick-borne flaviviruses. | the mosquito-borne west nile (wnv) and dengue 2 (den2v) viruses and tick-borne langat (lgtv) and omsk hemorrhagic fever (ohfv) viruses are arthropod-borne flaviviruses (family flaviviridae, genus flavivirus). these viruses are quite similar at both the nucleotide and amino acid level, yet they are very divergent in their biological properties and in the diseases they cause. the objective of this study was to examine the putative receptor-binding domains of the flaviviruses, the envelope (e) prot ... | 2004 | 15248774 |
| susceptibility of mosquito and tick cell lines to infection with various flaviviruses. | the genus flavivirus consists of more than 70 virus species and subtypes, the majority of which are transmitted by mosquitoes or ticks, although some have no known vector (nkv). the ability of these viruses to infect cultured cells derived from mosquito or tick species offers a useful insight into the suitability of such vectors to harbour and replicate particular viruses. we undertook a comparative study of the susceptibility of mammalian vero cells, a clonal mosquito cell line (c6/36) and rece ... | 2004 | 15347394 |
| tick-borne virus diseases of human interest in europe. | several human diseases in europe are caused by viruses transmitted by tick bite. these viruses belong to the genus flavivirus, and include tick-borne encephalitis virus, omsk haemorrhagic fever virus, louping ill virus, powassan virus, nairovirus (crimean-congo haemorrhagic fever virus) and coltivirus (eyach virus). all of these viruses cause more or less severe neurological diseases, and some are also responsible for haemorrhagic fever. the epidemiology, clinical picture and methods for diagnos ... | 2004 | 15606630 |
| tick-borne viruses. | at least 38 viral species are transmitted by ticks. virus-tick-vertebrate host relationships are highly specific and less than 10% of all tick species (argasidae and ixodidae) are known to play a role as vectors of arboviruses. however, a few tick species transmit several (e.g. ixodes ricinus, amblyomma variegatum) or many (i. uriae) tick-borne viruses. tick-borne viruses are found in six different virus families (asfarviridae, reoviridae, rhabdoviridae, orthomyxoviridae, bunyaviridae, flaviviri ... | 2004 | 15938513 |
| extension of ixodes ricinus ticks and agents of tick-borne diseases to mountain areas in the czech republic. | along with the shift of the hard tick ixodes ricinus to higher altitudes observed in the czech republic a corresponding shift of tick-borne infections to higher altitudes has been expected. therefore, i. ricinus ticks, mainly nymphs, were investigated for the presence of tick-borne viruses, tick-borne encephalitis (tbe), tribec and eyach, and the spirochaete borrelia burgdorferi sensu lato in the sumava and krkonose mountains (czech republic). the tbe virus and different genospecies of b. burgdo ... | 2006 | 16545603 |
| kyasanur forest disease: an epidemiological view in india. | kyasanur forest disease (kfd) was first recognised as a febrile illness in the shimoga district of karnataka state of india. the causative agent, kfd virus (kfdv), is a highly pathogenic member in the family flaviviridae, producing a haemorrhagic disease in infected human beings. kfd is a zoonotic disease and has so far been localised only in a southern part of india. the exact cause of its emergence in the mid 1950s is not known. a variant of kfdv, characterised serologically and genetically as ... | 2006 | 16710839 |
| tickborne arbovirus surveillance in market livestock, nairobi, kenya. | to identify tickborne viruses circulating in kenya and the surrounding region, we conducted surveillance at abattoirs in nairobi, kenya. species of ticks collected included rhipicephalus pulchellus (56%), amblyomma gemma (14%), r. appendiculatus (8%), a. variegatum (6%), and others. a total of 56 virus isolates were obtained, 26 from a. gemma, 17 from r. pulchellus, 6 from a. variegatum, and 7 from other species. virus isolates included dugbe virus (dugv), an unknown virus related to dugv, thogo ... | 2006 | 16836823 |
| [crimean-congo hemorrhagic fever]. | crimean-congo hemorrhagic fever (cchf) virus is a tick-borne virus, which is a member of bunyaviridae family, nairovirus genus. cchf virus has been isolated from 31 different tick species so far, and genus hyalomma includes the basic vectors of which h. anatolicum, h. marginatum, h. detritum, h. dromedarii, h. excavatum and h. turanicum are frequently found in the geography in which turkey takes place. the virus is transmitted via the bite of infected ticks or direct contact with cchf infected p ... | 2006 | 17001860 |
| crimean-congo hemorrhagic fever virus: genetic analysis and tick survey in turkey. | crimean-congo hemorrhagic fever virus (cchfv) is a tick-borne virus in the family bunyaviridae, genus nairovirus. the virus is transmitted to humans through infected tick bites or from direct contact with viremic animals or humans. in the present study, a total of 1,015 adult ticks were collected from cattle (603 specimens), sheep (17 specimens), and goats (395 specimens) in the kelkit valley in turkey. four tick species were recognized on the animals in the surveyed region. the most abundant sp ... | 2006 | 17088370 |
| antibodies to certain arboviruses in humans from a flooded village in egypt. | a study was carried out on 180 sera collected from inhabitants of a seepage flooded village (begiram) in a nile delta governorate in egypt. the aim of the study was to monitor the prevalence of certain arboviruses; some of them are known to be endemic in egypt. sera were screened by elisa except for the htn by if, and the results indicated that wn and sfs exhibited the highest prevalence 45.5% followed by sfn (21%). these 3 viruses are known to be endemic in egypt. the high prevalence of w.n. an ... | 1994 | 17265641 |
| host range specificity of flaviviruses: correlation with in vitro replication. | vector-borne flaviviruses have been traditionally grouped into either mosquito-borne or tick-borne group. however, this vector range specificity has sometimes been questioned because of the puzzling records of occasional isolation of mosquito-borne viruses from ticks and of tick-borne viruses from mosquitoes. in this study, host range of the flaviviruses representing not only the two vector-borne groups but also insect flaviviruses and vertebrate viruses that are not arboviruses was comprehensiv ... | 2007 | 17294926 |
| dhori virus (orthomyxoviridae: thogotovirus) infection in mice: a model of the pathogenesis of severe orthomyxovirus infection. | after intranasal, subcutaneous, or intraperitoneal infection with dhori virus (dhov), adult mice developed a fulminant and uniformly fatal illness with many of the clinical and pathologic findings seen in mice infected with h5n1 highly pathogenic avian influenza a virus. histopathologic findings in lungs of dhov-infected mice consisted of hemorrhage, inflammation, and thickening of the interstitium and the alveolar septa and alveolar edema. extra-pulmonary findings included hepatocellular necros ... | 2007 | 17426188 |
| recent progress in molecular biology of crimean-congo hemorrhagic fever. | crimean-congo hemorrhagic fever (cchf) is a severe hemorrhagic fever in humans with a case fatality rate of up to 50%. a causative agent of cchf is cchf virus, which is a tick-borne virus in the family bunyaviridae, genus nairovirus. the virus is transmitted to humans through infected tick bites, squashed ticks or from direct contact with viremic animals or humans. outbreaks of cchf have been documented in africa, the middle east, eastern europe and western asia where the vector and/or reservoir ... | 2007 | 17692916 |
| development of a taqman minor groove binding protein assay for the detection and quantification of crimean-congo hemorrhagic fever virus. | crimean-congo hemorrhagic fever virus (cchfv) is a tick-borne virus of the genus nairovirus and the family bunyaviridae. it is a negative-strand rna virus comprised of small (s), medium (m), and large (l) genome segments. the s segment encodes for nucleocapsid protein, the m segment codes for envelope glycoproteins (gn and gc), and the l segment codes for the rna-dependent rna polymerase. currently, there are a limited number of methods for rapidly diagnosing cchfv infections. we developed a rea ... | 2007 | 17827370 |
| [organization of supervision of tick-borne encephalitis and ways of its prevention in the russian federation]. | the paper presents the data characterizing the epidemiological situation associated with tick-borne virus encephalitis (tbve) in the russian federation in 2006. there is a 22.7% reduction in morbidity as compared with 2005; however, the situation is considered to be of strain; a rise in the incidence of tbve is recorded in a number of subjects of the russian federation. there is a high activity of natural and anthropurgic foci of tbve; there are as many as 250 recourses to a doctor for tick bite ... | 2007 | 18041217 |
| man-threatening viruses isolated from ticks in saudi arabia. | to determine tick viruses transmissible to man in saudi arabia. | 2007 | 18060218 |
| treatment of crimean-congo hemorrhagic fever. | crimean-congo hemorrhagic fever (cchf) has the most extensive geographic range of the medically significant tick-borne viruses, occurring from western china across southern asia to eastern europe and south africa. the causative agent is a negative-sense, single-stranded rna virus in the genus nairovirus, family bunyaviridae. in published reports, the case fatality rate has generally ranged from 10% to 50%. sporadic cases and outbreaks of the disease have increased during the past decade across t ... | 2008 | 18096251 |