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clinical signs and pathology shown by british sheep and cattle infected with bluetongue virus serotype 8 derived from the 2006 outbreak in northern europe.four poll dorset sheep and four holstein-friesian cattle were infected with the northern european strain of bluetongue virus (btv), btv-8, to assess its pathogenicity in uk breeds. the time course of infection was monitored in both species by using real-time reverse transcriptase-pcr (rt-pcr), conventional rt-pcr and serology. two of the sheep developed severe clinical signs that would have been fatal in the field; the other two were moderately and mildly ill, respectively. the cattle were clini ...200717720961
clinical signs of bluetongue virus serotype 8 infection in sheep and goats. 200717965371
evaluation of antibody-elisa and real-time rt-pcr for the diagnosis and profiling of bluetongue virus serotype 8 during the epidemic in belgium in 2006.in 2006 bluetongue (bt) emerged for the first time in north-western europe. reliable diagnostic tools are essential in controlling bt but data on the diagnostic sensitivity (se) and specificity (sp) are often missing. this paper aims to describe and analyse the results obtained with the diagnostics used in belgium during the 2006 bt crisis. the diagnosis was based on a combination of antibody detection (competitive elisa, celisa) and viral rna detection by real-time rt-pcr (rt-qpcr). the perform ...200818093753
performance of clinical signs to detect bluetongue virus serotype 8 outbreaks in cattle and sheep during the 2006-epidemic in the netherlands.the performance of clinical signs as a diagnostic test for the detection of btv-8 outbreaks during the 2006-epidemic in the netherlands was evaluated by constructing and analysing receiver operating characteristic (roc) curves. the area under the roc curve of the bt-associated clinical signs in cattle was 0.77. an optimal efficient test (maximising both sensitivity and specificity) in cattle herds combined a sensitivity (se) of 67% with a specificity (sp) of 72%, comprising the following clinica ...200818164148
[epidemiology of bluetongue virus serotype 8 outbreaks in the netherlands in 2006].in august 2006 a major epidemic of bluetongue (bt) occurred in north-western europe, affecting the netherlands, belgium, germany, luxemburg, and the north of france. it was caused by br virus serotype 8 (btv-8), a serotype previously unknown to the eu. although clinical disease is usually restricted to sheep, this virus also caused clinical disease in a small proportion of cattle. the last clinical outbreak of bt in the netherlands occurred mid-december 2006. the delay between observation of the ...200818429403
bluetongue virus serotype 8-associated congenital hydranencephaly in calves.hydranencephaly, the almost complete absence of the cerebral parenchyma, induced by infection with modified live bluetongue virus (btv) crossing the placenta has previously been reported in sheep and rarely in cattle in the usa and in south africa. the current study describes 29 cases of hydranencephaly in bovine foetuses and 'dummy' calves up to 3 months of age in belgium associated with natural btv serotype 8 infection very early in gestation. histological examination of the remaining cerebral ...200818503510
sequence analysis of bluetongue virus serotype 8 from the netherlands 2006 and comparison to other european strains.during 2006 the first outbreak of bluetongue ever recorded in northern europe started in belgium and the netherlands, spreading to luxemburg, germany and north-east france. the virus overwintered (2006-2007) reappearing during may-june 2007 with greatly increased severity in affected areas, spreading further into germany and france, reaching denmark, switzerland, the czech republic and the uk. infected animals were also imported into poland, italy, spain and the uk. an initial isolate from the n ...200818570969
evidence for transplacental transmission of the current wild-type strain of bluetongue virus serotype 8 in cattle. 200818621997
modelling local dispersal of bluetongue virus serotype 8 using random walk.the knowledge of the place where a disease is first introduced and from where it later spreads is a key element for the understanding of an epizootic. for a contagious disease, the main method is back tracing. for a vector-borne disease such as the bluetongue virus serotype 8 epizootic that occurred in 2006 in north-western europe, the efficiency of tracing is limited because many infected animals are not showing clinical signs. in the present study, we propose to use a statistical approach, ran ...200818640733
impact of human interventions on the spread of bluetongue virus serotype 8 during the 2006 epidemic in north-western europe.bluetongue virus (btv) can be spread by movement or migration of infected ruminants. infected midges (culicoides sp.) can be dispersed with livestock or on the wind. transmissions of infection from host to host by semen and trans-placental infection of the embryo from the dam have been found. as for any infectious animal disease, the spread of btv can be heavily influenced by human interventions preventing or facilitating the transmission pathways. this paper describes the results of investigati ...200818649960
possible routes of introduction of bluetongue virus serotype 8 into the epicentre of the 2006 epidemic in north-western europe.in august 2006, bluetongue (bt) was notified in the netherlands on several animal holdings. this was the onset of a rapidly spreading bt-epidemic in north-western europe (latitude >51 degrees n) that affected cattle and sheep holdings in the netherlands, belgium, germany, france and luxembourg. the outbreaks were caused by bluetongue virus (btv) serotype 8, which had not been identified in the european union before. bluetongue virus can be introduced into a free area by movement of infected rumi ...200818667252
transplacental infection and apparently immunotolerance induced by a wild-type bluetongue virus serotype 8 natural infection.until recently, bluetongue (bt) virus (btv) serotypes reportedly causing transplacental infections were all ascribed to the use of modified live virus strains. during the 2007 bt epidemic in belgium, a significant increase in the incidence of abortions was reported. a study including 1348 foetuses, newborns and young animals with or without suspicion of btv infection, was conducted to investigate the occurrence of natural transplacental infection caused by wild-type btv-8 and to check the immuno ...200818673339
evidence for transplacental and contact transmission of bluetongue virus in cattle.this paper presents evidence that a field strain of bluetongue virus serotype 8 (btv-8) was transmitted transplacentally and that it was also spread by a direct contact route. twenty pregnant heifers were imported from the netherlands into northern ireland during the midge-free season. tests before and after the animals were imported showed that eight of them had antibodies to bluetongue virus, but no viral rna was detected in any of them by reverse transcriptase-pcr (rt-pcr). two of the seropos ...200818708653
[bluetongue virus serotype 8 (btv-8)-associated brain malformations in two calves].congenital brain malformations such as hydranencephaly as well as internal and external hydrocephalus combined with porencephaly were diagnosed in two calves which were born in spring 2008. in both calves bluetongue virus was detected by real-time pcr. teratogenic pestiviruses were not found by serological, molecular or immunohistological methods. a causal relationship between the malformations and the bluetongue serotype 8 epidemic in 2007 has to be considered.200818717057
a cross-sectional study to determine the seroprevalence of bluetongue virus serotype 8 in sheep and goats in 2006 and 2007 in the netherlands.in august 2006 a major epidemic of bluetongue virus serotype 8 (btv8) started off in north-west europe. in the course of 2007 it became evident that btv8 had survived the winter in north-west europe, re-emerged and spread exponentially. recently, the european union decided to start vaccination against btv8. in order to improve the understanding of the epidemiological situation, it was necessary to execute a cross-sectional serological study at the end of the bt vector season. cattle were the tar ...200818752681
bluetongue virus serotype 8 reemergence in germany, 2007 and 2008.reemerging bluetongue virus serotype 8 (btv-8) in germany was detected first in may 2007 in a sentinel cow and in february 2008 in an export heifer. reemergence was confirmed by retesting the samples, experimental inoculation, fingerprinting analysis, and virus isolation. overwintering of btv-8 and continuous low-level infections are assumed.200818760009
[bluetongue disease in swiss sheep breeds: clinical signs after experimental infection with bluetongue virus serotype 8].clinical disease of bluetongue (bt) in sheep may differ depending on breed, age and immunity of infected sheep and may also vary between serotype and strain of bt virus (btv). since there are no data available on the susceptibility of swiss sheep breeds for bt, we performed experimental infection of the 4 most common swiss sheep breeds and the highly susceptible poll dorset sheep with the btv serotype 8 (btv-8) circulating in northern europe since 2006. clinical signs were assessed regarding sev ...200818821508
seroprevalence of bluetongue serotype 8 in cattle in the netherlands in spring 2007, and its consequences.a cross-sectional study was carried out in spring 2007, at the end of the first bluetongue outbreak season, to determine the geographical spread of bluetongue virus serotype 8 (btv-8) infection in cattle in the netherlands and the consequences for some production parameters. blood samples from cattle submitted to the laboratory of the dutch animal health service for other voluntary and obligatory health programmes were tested serologically for btv-8. in total, 37,073 samples were tested and 659 ...200818849575
bluetongue virus serotype 8 in the ardennes in 2007. 200819043098
experimental reproduction of bluetongue virus serotype 8 clinical disease in calves.cattle are commonly subclinically infected following natural or experimental infection with bluetongue virus (btv). the introduction of btv serotype 8 (btv-8) in europe has been characterized by the manifestation of clinical signs in infected cattle. in order to study the pathogenesis of btv-8 in this host, an animal model able to reproduce the clinical manifestations of the disease is required. in this work, two calves were subcutaneously and intravenously injected with a low passage cell-adapt ...200919128895
[bluetongue virus serotype 8 in healthy young calves].following the detection in northern ireland of bluetongue serotype-8 (btv-8) pcr-positive calves born from pcr-negative but seropositive heifers imported from the netherlands, an investigation was started to determine whether pcr-positive calves were born in the first quarter of 2008 in the netherlands. blood samples were collected on 43 dairy farms from 388 cow-calf combinations. all calves were at least 10-days-old and had been born after 1 january 2008. in total, 229 cows had had a btv-8 infe ...200819133436
epidemiology of bluetongue virus serotype 8, germany.in germany, bluetongue disease had not been reported before 2006. during august 2006-august 2008, >24,000 bluetongue virus serotype 8 infections were reported, most (20,635) in 2007. in 2006 and 2007, respectively, case-fatality rates were 6.4% and 13.1% for cattle and 37.5% and 41.5% for sheep. vaccination in 2008 decreased cases.200919239757
[vaccination against bluetongue: safety and immune response in the field].bluetongue, caused by the bluetongue virus serotype 8 has rapidly spread through europe since 2006. the first cases in switzerland were detected in october 2007. the european union and switzerland launched a vaccination campaign in june 2008. this study aims to demonstrate the safety and the immune response of the three vaccines used in switzerland under practical conditions in the field. the trial was carried out in cattle, sheep and goats. based on the results of this study recommendations for ...200919263379
experimental transplacental infection of sheep with bluetongue virus serotype 8. 200919377090
efficacy of three inactivated vaccines against bluetongue virus serotype 8 in sheep.bluetongue has become a major animal health issue in the european union. the member states and switzerland have agreed on a vaccination strategy. three different inactivated monovalent vaccines against bluetongue virus serotype 8 were selected for the compulsory vaccination program carried out in germany in 2008. the efficacy of these vaccines was evaluated in a pilot study in sheep immunised under field conditions by clinical, virological and serological examination before and after experimenta ...200919406189
comparative safety study of three inactivated btv-8 vaccines in sheep and cattle under field conditions.after massive epidemics of bluetongue disease in 2006 and 2007, germany has started a compulsory vaccination program against bluetongue virus serotype 8 (btv-8). since the available vaccines had not yet been registered and only limited data were available on their performance, a safety study was conducted with three different inactivated monovalent vaccines under consideration for use in germany. a total of 1007 sheep and 893 cattle were vaccinated and subsequently compared with 638 control anim ...200919410620
transplacental and oral transmission of wild-type bluetongue virus serotype 8 in cattle after experimental infection.potential vertical transmission of wild-type bluetongue virus serotype 8 (btv-8) in cattle was explored in this experiment. we demonstrated transplacental transmission of wild-type btv-8 in one calf and oral infection with btv-8 in another calf. following the experimental btv-8 infection of seven out of fifteen multi-parous cows eight months in gestation, each newborn calf was tested prior to colostrum intake for transplacental transmission of btv by rrt-pcr. if transplacental transmission was n ...200919419822
genebank accession numbers of sequences of culicoides species vectors of bluetongue virus in germany.the paper offers the genebank accession numbers of culicoides obsoletus, culicoides scoticus and culicoides pulicaris sequences (its 1, its 2, 18s rrna) that had been shown to be vectors of the bluetongue virus serotype 8, which was introduced in 2006 into germany and spread until 2009 all over central europe, including parts of england. the numbers are fn 263292 until fn 263323.200919424722
segment 10 based molecular epidemiology of bluetongue virus (btv) isolates from turkey: 1999-2001.bluetongue is a significant arbovirus infection that has a negative impact on ruminant productivity in turkey. twenty-one turkish btv isolates were analyzed phylogenetically, based on genome segment 10 (seg-10) nucleotide sequences. these analyses were used to explore the epidemiological background of individual isolates from both a regional and global perspective. in the regional analysis, the different btv strains fell into two groups (group 1 and group 2). the turkish virus isolates were loca ...200919428746
epizootic congenital hydranencephaly and abortion in cattle due to bluetongue virus serotype 8 in the netherlands.an outbreak of hydranencephaly in aborted foetuses and newborn calves occurred following the 2007 epidemic of bluetongue serotype 8 (btv8\net2006) in the netherlands. in total 35 aborted foetuses and 20 live-born calves, submitted from september 2007 to may 2008, were examined pathologically. foetuses with gestational ages between 4 and 9 months (mean 6.8 month) showed varying stages of cerebral malformation. initial stages were cavitations in the cerebral hemispheres with massive destruction of ...200919522347
establishing a cost-effective national surveillance system for bluetongue using scenario tree modelling.vector-borne diseases pose a special challenge to veterinary authorities due to complex and time-consuming surveillance programs taking into account vector habitat. using stochastic scenario tree modelling, each possible surveillance activity of a future surveillance system can be evaluated with regard to its sensitivity and the expected cost. the overall sensitivity of various potential surveillance systems, composed of different combinations of surveillance activities, is calculated and the pr ...200919607784
vertical transmission of bluetongue virus serotype 8 virus in dutch dairy herds in 2007.in february 2008, evidence was found for transplacental infection of bluetongue virus serotype 8 (btv-8) in pcr negative, seropositive heifers in northern ireland originating from the netherlands. the relevance of this route of transmission was studied in dutch cow-calf combinations in the netherlands of which the calves were born in the same time period of the year as the calves from the exported heifers, the first quarter of 2008. blood samples were tested from 385 cows and their calves, house ...201019713058
epidemiologic characteristics of bluetongue virus serotype 8 laboratory-confirmed outbreaks in the netherlands in 2007 and a comparison with the situation in 2006.a major epidemic of bluetongue virus serotype 8 (btv-8) occurred in western europe in 2006. during 2007 it became evident that btv-8 had survived the winter and a re-emerging epidemic quickly developed. the objective of this study was to describe the severity and clinical impact of the btv-8 epidemic in 2007 in the netherlands in laboratory-confirmed outbreaks and to compare this with the situation in 2006. the relative frequency of clinical signs in btv-8 affected sheep flocks and cattle herds ...200919740560
use of inactivated bluetongue virus serotype 8 vaccine against virulent challenge in sheep and cattle.the immunisation properties of an inactivated bluetongue virus serotype 8 (btv-8) vaccine were evaluated in sheep and cattle. five sheep were vaccinated with one dose of vaccine and five cattle were vaccinated with two doses 28 days apart. six sheep and five cattle served as unvaccinated controls. all animals were subjected to a virulent btv-8 challenge, and safety and antibody responses were monitored. all control animals developed disease and viraemia, while vaccinated animals were clinically ...200919783850
seroconversion, neutralising antibodies and protection in bluetongue serotype 8 vaccinated sheep.bluetongue virus serotype 8 (btv-8) has caused a major outbreak of disease in cattle and sheep in several countries across northern and western europe from 2006 to 2008. in 2008 the european union instigated a mass-vaccination programme in affected countries using whole virus inactivated vaccines. we evaluated vaccinal responses in sheep and the ability of the vaccine to protect against experimental challenge. sheep vaccinated 10 months previously under field conditions were challenged with btv- ...200919786141
monitoring of putative vectors of bluetongue virus serotype 8, germany.to identify the vectors of bluetongue virus (btv) in germany, we monitored culicoides spp. biting midges during april 2007-may 2008. molecular characterization of batches of midges that tested positive for btv suggests c. obsoletus sensu stricto as a relevant vector of bluetongue disease in central europe.200919788820
the increase in seroprevalence of bluetongue virus (btv) serotype 8 infections and associated risk factors in dutch dairy herds, in 2007.bluetongue virus serotype 8 (btv-8) emerged in the netherlands in august 2006 for the first time. in the winter of 2006/2007, during the transmission free period, the government decided to establish a sentinel network to monitor the re-emergence of btv-8 in 2007. between june and december 2007, a sentinel network of 275 dairy herds with 8901 seronegative cows at start, was in place for btv-8 testing in milk samples. besides estimates of the monthly btv-8 within-herd prevalence per region (south, ...201019945231
transplacental transmission of bluetongue virus 8 in cattle, uk.to determine whether transplacental transmission could explain overwintering of bluetongue virus in the united kingdom, we studied calves born to dams naturally infected during pregnancy in 2007-08. approximately 33% were infected transplacentally; some had compromised health. in all infected calves, viral load decreased after birth; no evidence of persistent infection was found.200919961692
the impact of naturally-occurring, trans-placental bluetongue virus serotype-8 infection on reproductive performance in sheep.infection with bluetongue virus serotype (btv)-8 occurred in ruminants in 2006 in central-western europe. the trans-placental passage of this virus has been demonstrated in naturally- and experimentally-infected cattle and in experimentally-infected sheep. trans-placental transmission is potentially important in the 'over-wintering' of this virus and its subsequent impact on reproductive performance. this epidemiological study was carried out on a sheep flock in belgium that had experienced a se ...201120061168
serological survey of bluetongue virus serotype-8 infection in south american camelids in switzerland (2007-2008).outbreak of bluetongue virus serotype-8 (btv-8) infection in domestic ruminants in northern europe.201020102499
colostral antibody protection and interference with immunity in lambs born from sheep vaccinated with an inactivated bluetongue serotype 8 vaccine.widespread vaccination programmes against bluetongue virus serotype 8 (btv-8), using inactivated vaccines, are being carried out across many countries in northern, western and southern europe. this study investigates the extent and length of colostral antibody protection, as well as the degree of colostral antibody induced interference of the immune response to btv-8, in sheep. significantly lower titres of neutralising antibodies were transferred in colostrum to lambs born from sheep vaccinated ...201020123052
questionnaire survey about the motives of commercial livestock farmers and hobby holders to vaccinate their animals against bluetongue virus serotype 8 in 2008-2009 in the netherlands.after a massive epidemic of bluetongue virus serotype 8 (btv-8) among ruminants in 2006-2007 in the european union (eu), the netherlands started a voluntary emergency vaccination campaign in may 2008, subsidized by the eu. at the start of a new campaign in 2009, without subsidized vaccination, we investigated by mail survey the motives of farmers and hobby holders to vaccinate against btv-8 in 2008 and 2009. mean vaccine uptake in 2008 was: 73% in sheep, 71% in cattle, 43% in goat farms and 67% ...201020123141
virological and pathological findings in bluetongue virus serotype 8 infected sheep.twenty-seven sheep of the four most common swiss breeds and the english breed poll dorset were experimentally infected with a northern european field strain of bluetongue virus serotype 8 (btv-8). animals of all breeds developed clinical signs, viremia and pathological lesions, demonstrating that btv-8 is fully capable of replicating and inducing bluetongue disease (bt) in the investigated sheep. necropsy performed between 10 and 16 days post-infectionem (d.p.i.) revealed bt-typical hemorrhages, ...201020153937
the spread of bluetongue virus serotype 8 in great britain and its control by vaccination.bluetongue (bt) is a viral disease of ruminants transmitted by culicoides biting midges and has the ability to spread rapidly over large distances. in the summer of 2006, btv serotype 8 (btv-8) emerged for the first time in northern europe, resulting in over 2000 infected farms by the end of the year. the virus subsequently overwintered and has since spread across much of europe, causing tens of thousands of livestock deaths. in august 2007, btv-8 reached great britain (gb), threatening the larg ...201020179768
potential role of ticks as vectors of bluetongue virus.when the first outbreak of bluetongue virus serotype 8 (btv8) was recorded in north-west europe in august 2006 and renewed outbreaks occurred in the summer of 2007 and again in 2008, the question was raised how the virus survived the winter. since most adult culicoides vector midges are assumed not to survive the northern european winter, and transovarial transmission in culicoides is not recorded, we examined the potential vector role of ixodid and argasid ticks for bluetongue virus. four speci ...201020358393
bluetongue virus in wild deer, belgium, 2005-2008.to investigate bluetongue virus serotype 8 infection in belgium, we conducted a virologic and serologic survey on 2,416 free-ranging cervids during 2005-2008. infection emerged in 2006 and spread over the study area in red deer, but not in roe deer.201020409376
evaluation of humoral response and protective efficacy of three inactivated vaccines against bluetongue virus serotype 8 one year after vaccination of sheep and cattle.the long-term efficacy of three commercially available inactivated vaccines against bluetongue virus serotype 8 (btv-8) (bluevac) 8, zulvac 8, and btvpur alsap 8) was evaluated in a seroprevalence study and challenge experiments. seroprevalences 1 year after vaccination ranged from 75% to 100%. in two infection experiments, groups of vaccinated sheep and cattle selected either randomly or for low antibody levels were challenged with a european btv-8 strain 12 months after vaccination. with two e ...201020438878
neutralising antibody responses in cattle and sheep following booster vaccination with two commercial inactivated bluetongue virus serotype 8 vaccines.cattle and sheep that had received a primary course of vaccination with an inactivated bluetongue virus serotype 8 (btv-8) vaccine were booster vaccinated 6 or 12 months later with the homologous vaccine or an alternative inactivated btv-8 vaccine and neutralising antibody responses were determined. antibody titres to the alternative vaccine were significantly higher than to the homologous vaccine (p=0.013) in cattle. there was no significant difference between the antibody responses to alternat ...201120466568
humoral response to 2 inactivated bluetongue virus serotype-8 vaccines in south american camelids.bluetongue virus serotype 8 (btv-8) has caused disease in domestic ruminants in several countries of northern europe since 2006. in 2008 a mass-vaccination program was launched in most affected countries using whole virus inactivated vaccines.201020492489
evaluation of an indirect elisa for detection of antibodies in bulk milk against bluetongue virus infections in the netherlands.after the introduction of bluetongue virus serotype 8 (btv-8) in western europe in 2006, an indirect elisa for detection of serogroup-specific antibodies against btv in serum samples was validated for individual milk samples by the central veterinary institute and the animal health service in the netherlands (kramps et al., 2008). in order to develop a cost-effective monitoring tool, we now have evaluated this elisa also for use in bulk milk. therefore, bulk milk samples and individual milk samp ...201020547015
antibody response in cattle vaccinated against bluetongue serotype 8 in italy.to assess the immunogenicity of zulvac 8 bovis (a commercial inactivated vaccine against bluetongue virus serotype 8 - btv8) under field conditions, 71 cattle vaccinated according to manufacturer schedule in verona province (italy) were tested for the presence of btv8 neutralizing antibodies at 21, 29, 36, 43, 49, 102 and 201 days post-vaccination (dpv). another group of 528 btv8 vaccinated cattle in mantova province (italy) was also tested once between 113 and 174 dpv. the vaccine was able to e ...201020569419
bluetongue virus rna detection by rt-qpcr in blood samples of sheep vaccinated with a commercially available inactivated btv-8 vaccine.in 2008, a country-wide bluetongue virus 8 (btv-8) vaccination campaign has been initiated in austria, using a single commercial inactivated btv-8 vaccine. based on preliminary data, we hypothesised that vaccine-derived btv rna is transiently detectable by reverse transcription quantitative real-time pcr (rt-qpcr) in the blood of vaccinated animals. thus btv-8 vaccine was administered to five btv-naïve adult sheep and blood samples were taken at various time-points post-vaccination. btv rna was ...201020600511
infection with bluetongue virus serotype 8 in sweden in 2008.on september 6, 2008, bluetongue was detected for the first time in sweden. intensified active surveillance in cattle and vector surveillance, prompted by the situation in northern europe, preceded the detection. a vaccination campaign and intensive surveillance activities were initiated nationally, but with a focus on the southern part of the country. measures included both active and passive surveillance by serology and pcr in ruminants, along with vector surveillance. the investigations revea ...201020675625
bluetongue virus serotype 8 (btv-8) infection reduces fertility of dutch dairy cattle and is vertically transmitted to offspring.in 2007, btv-8 re-emerged for the second year in the netherlands and caused morbidity and increased mortality in cattle herds. in addition, cattle farmers reported reduced fertility in their cows. for this study, fifteen herds that were not vaccinated were selected. these were matched to 10 vaccinated herds by geographic region. at the start of the study, in july 2008, all cattle in the non-vaccinated herds >1 year old were sampled. all seronegative cows entered the study program and blood sampl ...201020688368
bluetongue virus serotype 8-associated hydranencephaly in two calves in south-eastern england. 201020693506
expression and secretion of bluetongue virus serotype 8 (btv-8)vp2 outer capsid protein by mammalian cells.vp2 is the outermost bluetongue virus (btv) antigenic protein, forming triskelion motifs on the virion surface. although vp2 has been expressed successfully through many systems, its paracrine expression as a soluble form by mammalian cells represents a difficult task. in the present paper two fragments of vp2 have been expressed successfully into the medium of transiently transfected mammalian cells through a fusion peptides strategy. the crude conditioned medium containing the secreted peptide ...201020705105
experimental oral infection of bluetongue virus serotype 8 in type i interferon receptor-deficient mice.the identification of transmission routes for bluetongue virus (btv) is essential to improve the control of the disease. although btv is primarily transmitted by several species of culicoides biting midges, there has been evidence of transplacental and oral transmission. we now report that ifnar((-/-)) mice are susceptible to oral infection by btv-8. viraemia, clinical manifestations and tissue lesions are similar to those in intravenously infected mice. in addition, we show that the oral cavity ...201020719994
possible means of introduction of bluetongue virus serotype 8 (btv-8) to sweden in august 2008: comparison of results from two models for atmospheric transport of the culicoides vector.in september 2008, bluetongue virus serotype 8 (btv-8) infection was detected for the first time in sweden, in a dairy herd on the west coast. two different previously published operational atmospheric dispersion models indicate that midges from infected regions in europe are likely to have reached sweden by atmospheric transport during an estimated infection window. both models indicated that the likely dates for the incursion of midges were overnight on august 6 to 7 and august 14 to 15; howev ...201020871082
mortality attributable to bluetongue virus serotype 8 infection in dutch dairy cows.in 2007, bluetongue virus serotype 8 (btv-8) re-emerged in the netherlands and a large number of farmers notified morbidity and mortality associated with btv-8 to the authorities. all dead cows in the netherlands are registered in one of the three age classes: newborn calves <3 days, calves 3 days to 1 year, and cows >1 year. these registrations result in a complete data set of dead cattle per herd per day from 2003 until 2007. in this study, the mortality associated with btv-8 for the dutch dai ...201020889271
anatomy of bluetongue virus serotype 8 epizootic wave, france, 2007-2008.the introduction of bluetongue virus serotype 8 into northern europe at the end of summer 2006 initiated one of the most widespread epizootics of bluetongue infection ever to occur. in winter 2007-2008, a cross-sectional serologic study was conducted in france along a transect perpendicular to the epizootic wave. cattle herd-level seroprevalence varied from 4% to 100%, and animal-level seroprevalence from <1% to 40%. only a low proportion of seropositive herds reported clinical cases in 2007. sh ...201021122214
the susceptibility of culicoides imicola and other south african livestock-associated culicoides species to infection with bluetongue virus serotype 8.in 2006, a strain of bluetongue virus serotype 8 (btv-8) of sub-saharan origin was responsible for the first outbreaks in recorded history of clinical bluetongue disease (bt) in northern europe. in this study, we examine the oral susceptibility of culicoides (avaritia) imicola kieffer (diptera: ceratopogonidae) and other livestock-associated culicoides species from southern africa to infection with several strains of btv-8. following feeding using an artificial membrane-based method and incubati ...201021133962
transplacental transmission of bluetongue virus serotype 8 in ewes in early and mid gestation.the ability of bluetongue virus serotype 8 (btv-8) originating from the 2006 european outbreak to cross the ovine placenta during early and mid gestation was investigated in two separate experiments. in the first experiment, 16 ewes were infected with btv-8 at 70-75 days gestation. the foetuses were collected at 18-19 days after infection (dpi). btv-8 could be isolated from at least two organs of 19 out of 40 lambs and from 11 out of 16 infected ewes. in the second experiment, 20 btv-8 infected ...201021145670
evaluation of humoral response and protective efficacy of two inactivated vaccines against bluetongue virus after vaccination of goats.bluetongue serotype 8 has become a major animal health issue in the european union and the european member states have agreed on a vaccination strategy, which involves only inactivated vaccines. in this study, the efficacy of two inactivated vaccines against bluetongue virus serotype 8 (btv-8) used in europe since 2008, btvpur alsap(®) 8 (merial) and bovilis(®) btv8 (intervet/sp-ah), was evaluated in goats immunized and challenged with btv-8 field isolates under experimental conditions. serologi ...201121256877
oesophageal paresis associated with bluetongue virus serotype 8 in cattle. 201021257422
colostral antibody induced interference of inactivated bluetongue serotype-8 vaccines in calves.abstract: since its introduction into northern europe in 2006, bluetongue has become a major threat to animal health. while the efficacy of commercial vaccines has been clearly demonstrated in livestock, little is known regarding the effect of maternal immunity on vaccinal efficacy. here, we have investigated the duration and amplitude of colostral antibody-induced immunity in calves born to dams vaccinated against bluetongue virus serotype 8 (btv-8) and the extent of colostral antibody-induced ...201121314901
susceptibility of in vitro produced hatched bovine blastocysts to infection with bluetongue virus serotype 8.abstract: bluetongue virus serotype 8 (btv-8), which caused an epidemic in ruminants in central western europe in 2006 and 2007, seems to differ from other bluetongue serotypes in that it can spread transplacentally and has been associated with an increased incidence of abortion and other reproductive problems. for these reasons, and also because btv-8 is threatening to spread to other parts of the world, there is a need for more information on the consequences of infection during pregnancy. the ...201121314973
the effect of bluetongue virus serotype 8 on milk production and somatic cell count in dutch dairy cows in 2008.the effect of bluetongue virus serotype 8 (btv-8) infections was quantified on milk production and udder health. from july 2008 to december 2008, 1,074 seronegative cows in 15 herds that were not vaccinated against btv-8 were tested every 3 wk for btv-8 antibodies. sampling stopped when cows seroconverted. test-day records were provided and 3 traits were defined to evaluate the effect of btv-8 on milk production and udder health: 1) the difference between observed and predicted fat- and protein- ...201121338800
assessing the consequences of an incursion of a vector-borne disease i. identifying feasible incursion scenarios for bluetongue in scotland.following the arrival of bluetongue virus serotype 8 (btv-8) in southeast england in september 2007, the scottish government commissioned research to assess the economic consequences of a btv-8 incursion to scotland. here we present the first component of the assessment, which entailed identifying feasible incursion scenarios for the virus. our analyses focused on three routes of introduction: wind-borne dispersal of infected vectors, import of infected animals and northwards spread of btv from ...201021352785
two alternative inocula to reproduce bluetongue virus serotype 8 disease in calves.the aim of this study was to investigate the consequences in calves of two forms of inocula alternative to the use of wild type infectious blood. two groups of five calves were infected with low cell-passaged virus and infectious blood issued from one animal passage of the same strain. a longitudinal study was implemented and characterised by clinical standardised observations, haematology, btv rna detection and viral isolation from blood, detection of serogroup and neutralising antibodies, cyto ...201121376798
quantitative analysis of transmission parameters for bluetongue virus serotype 8 in western europe in 2006.abstract: the recent bluetongue virus serotype 8 (btv-8) epidemic in western europe struck hard. controlling the infection was difficult and a good and safe vaccine was not available until the spring of 2008. little was known regarding btv transmission in western europe or the efficacy of control measures. quantitative details on transmission are essential to assess the potential and efficacy of such measures.to quantify virus transmission between herds, a temporal and a spatio-temporal analysis ...201121435234
bluetongue serotype 8 vaccine coverage in northern and south-eastern england in 2008.a postal survey of all registered cattle and sheep farmers in east anglia was carried out from july 2008 to determine bluetongue virus serotype 8 (btv-8) vaccine uptake in the region. the vaccine was available to farmers in this region from may 2008. the survey was repeated in cumbria and northumberland at the beginning of 2009. in these regions, the vaccine was not available until september 1, 2008. holding-level vaccine uptake was estimated to be 85 per cent (95 per cent confidence interval [c ...201121493449
financial evaluation of different vaccination strategies for controlling the bluetongue virus serotype 8 epidemic in the netherlands in 2008.bluetongue (bt) is a vector-borne disease of ruminants caused by bluetongue virus that is transmitted by biting midges (culicoides spp.). in 2006, the introduction of btv serotype 8 (btv-8) caused a severe epidemic in western and central europe. the principal effective veterinary measure in response to bt was believed to be vaccination accompanied by other measures such as movement restrictions and surveillance. as the number of vaccine doses available at the start of the vaccination campaign wa ...201121573195
the presence of bluetongue virus serotype 8 rna in belgian cattle since 2008.after a short winter break, bluetongue virus serotype 8 was responsible in 2007 for a large-scale epidemic among ruminant populations in western europe. little is known about the mechanisms allowing the virus to survive winter conditions. a yearly mass vaccination of cattle and sheep started in spring 2008, which was recognized as successful in terms of clinical protection, but occult circulation of the bluetongue virus has not been adequately addressed. we studied the carriage of bluetongue rna ...201121605347
[bluetongue disease: impact of the 2008 vaccination on fertility in supervised dairy herds.]in june 2008 the compulsary nationwide vaccination against btv-8 (bluetongue virus serotype 8) was started. after a short time, several owners complained about undesirable effects of the vaccination on fertility and milk quality. data from 47 dairy farms, regularly supervised by herd health practitioners, were analysed in order to clarify a possible connection between vaccination and fertility. both vaccinations given each cow for basic immunization were evaluated according to their effects on c ...201121638261
viral rna load in semen from bluetongue serotype 8-infected rams: relationship with sperm quality.this study investigated if viral rna was detectable in the semen of rams clinically infected with bluetongue virus serotype 8 (btv-8) by rt-qpcr, and to what extent the amount detected may be predictive of sperm quality. semen samples were collected on six occasions from 93 btv-8 infected rams involved in two longitudinal (n=12 and 27, respectively) and one cross-sectional (n=54) field study. semen quality was assessed in terms of mass motility, concentration of spermatozoa, percentage of living ...201121802323
a side effect of decreased fertility associated with vaccination against bluetongue virus serotype 8 in holstein dairy cows.inactivated virus vaccines have been widely used to control bluetongue after introduction of serotype 8 of the bluetongue virus (btv) in northern europe in 2006. to evaluate vaccination, quantitative knowledge of its possible side effects is needed. one current adverse reaction with inactivated vaccines is a rise in body temperature, which could reduce cow reproductive performance. the objective of this study was to quantify a possible side effect of vaccination on fertility before the implantat ...201121676477
Seasonal spread and control of Bluetongue in cattle.Bluetongue is a seasonal midge-borne disease of ruminants with economic consequences on herd productivity and animal trade. Recently, two new modes of transmission have been demonstrated in cattle for Bluetongue virus serotype 8 (BTV8): vertical and pseudo-vertical transmission. Our objective was to model the seasonal spread of BTV8 over several years in a homogeneous population of cattle, and to evaluate the effectiveness of vaccination strategies. We built a deterministic mathematical model ac ...201121945148
Clinical disease in sheep caused by bluetongue virus serotype 8, and prevention by an inactivated vaccine.The ability to reduce clinical signs, induce neutralizing antibodies, and perhaps most importantly, to prevent or reduce viraemia (and therefore virus-transmission), represent primary criteria for assessment of bluetongue virus (BTV) vaccine efficacy. Identification of BTV challenge-strains that reliably induce viraemia and clinical signs comparable to those in naturally infected animals, is therefore important for vaccine evaluation. Texel cross-breed and Dorset Poll sheep vaccinated with inact ...201122207091
economic evaluation of the surveillance and intervention programme for bluetongue virus serotype 8 in switzerland.empirical analyses founded on sound economic principles are essential in advising policy makers on the efficiency of resource use for disease mitigation. surveillance and intervention are resource-using activities directed at mitigation. surveillance helps to offset negative disease effects by promoting successful intervention. intervention is the process of implementing measures (e.g. vaccination or medication) to reduce or remove a hazard in a population. the scale and ratios in which the two ...201222018548
a new tool for the molecular identification of culicoides species of the obsoletus group: the glass slide microarray approach.culicoides species of the obsoletus group (diptera: ceratopogonidae) are potential vectors of bluetongue virus serotype 8 (btv 8), which was introduced into central western europe in 2006. correct morphological species identification of obsoletus group females is especially difficult and molecular identification is the method of choice. in this study we present a new molecular tool based on probe hybridization using a dna microarray format to identify culicoides species of the obsoletus group. t ...201121973187
Bluetongue virus serotype 8: Abortion and transplacental transmission in cattle in the Burgundy region, France, 2008-2009.During the incursion of bluetongue virus (BTV) serotype 8 in France in 2007, an increase in the number of abortions in cattle was observed, but the cause was not clearly established. A survey of all the reported cases of abortion in cattle from November 2008 to April 2009 was conducted in the Nièvre district (Burgundy region) to determine the percentage of abortions as a result of BTV-8 and to study factors that could have played a role in BTV-8 transplacental transmission. BTV-8 was present in ...201221872306
Effect of vaccination with an inactivated vaccine on transplacental transmission of BTV-8 in mid term pregnant ewes and heifers.The effect of vaccination with a commercial inactivated Bluetongue virus serotype 8 (BTV-8) vaccine on the ability of BTV-8 to cross the ruminant placenta was investigated in two experiments. Ten pregnant ewes (Experiment 1) or heifers (Experiment 2) were vaccinated according to the manufacturer's instructions. Three weeks after the completion of the vaccination schedule, all vaccinated animals were infected with BTV-8 together with ten non-vaccinated pregnant animals that served as challenged c ...201222107846
[bovine neonatal pancytopenia in german holstein calves].profiles of blood cell counts were evaluated for 15 calves from three different farms. these calves showed petechia in the mucous membranes and in the skin and prolonged secondary bleeding after puncture. the clinical course of the disease could be observed in eleven calves. with exception of one case, the blood cell counts indicated a severe anaemia, leukocytopenia and thrombocytopenia. out of these 15 calves, six calves survived and the other nine calves died or had to be euthanized due to the ...201121848041
Experimental infection of South American camelids with bluetongue virus serotype 8.Bluetongue (BT) is an infectious, non-contagious disease of wild and domestic ruminants. It is caused by bluetongue virus (BTV) and transmitted by Culicoides biting midges. Since 1998, BT has been emerging throughout Europe, threatening not only the naïve ruminant population. Historically, South American camelids (SAC) were considered to be resistant to BT disease. However, recent fatalities related to BTV in captive SAC have raised questions about their role in BTV epidemiology. Data on the sus ...201221862245
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