RESUMO
In September 2023, bluetongue virus serotype 3 (BTV-3) emerged in the Netherlands, infecting over five thousand livestock farms. In sheep, high morbidity and mortality rates were reported that were unlike previously described bluetongue outbreaks. This study aimed to quantify the impact of BTV-3 in the small ruminant population in the Netherlands in 2023. Sheep and goat movement census data and BTV-3 notification data were available from 2020 until the end of 2023. Data were aggregated to farm and week level and mortality indicators were calculated for lambs (<1 year) and adult animals (≥1 year). Population averaged GEE models with a Negative-binomial distribution and a log-link function correcting for repeated measures per farm in time were used to quantify the association between BTV-3 and mortality. In 2023, 2994 sheep farmers and 89 goat farmers notified clinical signs of BTV-3 to the NVWA. During this BTV-3 outbreak period, an additional 55,000 sheep died compared to the same period in 2020-2022. At flock level a high variety in mortality was observed, with a clear increase in mortality in both flocks that were not notified but that were located in infected areas and in flocks of which the farmer notified clinical signs. During the BTV-3 outbreak period, mortality in infected areas increased 4.2 (95â¯% CI: 4.0-4.3) times in sheep lambs (<1 year) and 4.6 (95â¯% CI: 4.4-4.8) times in sheep (≥1 year) compared to BTV-3 free areas. Flocks with a confirmed BTV-3 infection that were notified in September showed a 12.8 (95â¯% CI: 11.4-14.3) times higher mortality in lambs and a 15.1 (95â¯% CI: 13.7-16.6) times higher mortality in sheep compared to flocks in BTV-3 areas. In flocks of which the farmer notified clinical signs after September, mortality was 4.6 (95â¯% CI: 4.2-5.0) and 5.6 (95â¯% CI: 5.1-6.0) times higher in lambs and sheep compared BTV-3 areas respectively. In goats, around 4000 additional deaths were recorded during the BTV-3 outbreak period. In farms that were notified, mortality of goats (≥1 year) was 1.8 (95â¯% CI: 1.2-2.8) times higher compared to BTV-3 free areas. Since May 2024, multiple BTV-3 vaccines are available in the Netherlands. In June 2024, the first new infections of BTV-3 were confirmed in Dutch sheep flocks. Hopes are that with the possibility to vaccinate, the spread and impact of BTV-3 in the Netherlands will rapidly decline and that losses as observed in 2023 will no longer be seen.
Assuntos
Vírus Bluetongue , Bluetongue , Surtos de Doenças , Doenças das Cabras , Cabras , Sorogrupo , Animais , Bluetongue/epidemiologia , Bluetongue/mortalidade , Bluetongue/virologia , Países Baixos/epidemiologia , Ovinos , Surtos de Doenças/veterinária , Doenças das Cabras/epidemiologia , Doenças das Cabras/virologia , Doenças das Cabras/mortalidade , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/virologia , Doenças dos Ovinos/mortalidadeRESUMO
Hemorrhagic disease (HD) caused by bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) is the most important viral disease of farmed and wild white-tailed deer (WTD; Odocoileus virginianus) and can cause substantial mortality in susceptible hosts. Captive cervid farming is an emerging industry in Florida, an HD-enzootic region. Morbidity and mortality due to HD are major concerns among deer farmers, but the impact of HD on Florida's cervid farming industry is unknown. Our primary objective was to determine the prevalence of epizootic hemorrhagic disease virus (EHDV) and bluetongue virus (BTV) among WTD submitted to the University of Florida Institute of Food and Agricultural Sciences Cervidae Health Research Initiative (CHeRI) for post-mortem diagnostics. Our secondary objectives were to identify the predominant circulating EHDV serotypes during each sampling year and to determine the age class with the greatest proportion of EHDV- and BTV-positive post-mortem specimens. From 2016 to 2020, spleen samples from 539 farmed WTD with unexplained mortality were tested for the presence of EHDV and BTV by RT-qPCR. Overall, the prevalence of EHDV, BTV, or EHDV/BTV coinfection was 26%, 16%, and 10%, respectively, and 44% of deer (237/539) were diagnosed with HD by RT-qPCR. The predominant circulating EHDV serotype varied by year. Overall, EHDV-2 was the most commonly identified serotype (55% of PCR-positive cases), and EHDV-1 was the least frequently identified serotype (16% of PCR-positive cases). The greatest proportion of EHDV/BTV positives among mortality cases was observed in young WTD aged 3-6 months (50%-82% positive). There was a significant difference in the prevalence of EHDV/BTV by age when comparing specimens from WTD over 1 year old (p = 0.029, n = 527). Among these samples, the number of reported mortalities and the prevalence of EHDV/BTV were highest in yearling animals (56%). These data provide the first estimate of EHDV and BTV prevalence and virus serotypes among farmed WTD in Florida, identify the WTD age groups with the greatest proportions of EHDV- and BTV-positive specimens, and suggest that HD caused by these two viruses may be a major source of mortality challenging the captive cervid farming industry in Florida.
Assuntos
Bluetongue/epidemiologia , Bluetongue/mortalidade , Cervos/virologia , Fazendas/estatística & dados numéricos , Infecções por Reoviridae/mortalidade , Infecções por Reoviridae/veterinária , Animais , Anticorpos Antivirais/sangue , Vírus Bluetongue/genética , Vírus Bluetongue/patogenicidade , Feminino , Florida/epidemiologia , Vírus da Doença Hemorrágica Epizoótica/genética , Vírus da Doença Hemorrágica Epizoótica/patogenicidade , Masculino , Prevalência , Infecções por Reoviridae/epidemiologiaRESUMO
In September 2016, clinical signs, indicative of bluetongue, were observed in sheep in Cyprus. Bluetongue virus serotype 8 (BTV-8) was detected in sheep, indicating the first incursion of this serotype into Cyprus. Following virus propagation, Nextera XT DNA libraries were sequenced on the MiSeq instrument. Full-genome sequences were obtained for five isolates CYP2016/01-05 and the percent of nucleotide sequence (% nt) identity between them ranged from 99.92% to 99.95%, which corresponded to a few (2-5) amino acid changes. Based on the complete coding sequence, the Israeli ISR2008/13 (98.42-98.45%) was recognised as the closest relative to CYP2016/01-05. However, the phylogenetic reconstruction of CYP2016/01-05 revealed that the possibility of reassortment in several segments: 4, 7, 9 and 10. Based on the available sequencing data, the incursion BTV-8 into Cyprus most likely occurred from the neighbouring countries (e.g., Israel, Lebanon, Syria, or Jordan), where multiple BTV serotypes were co-circulating rather than from Europe (e.g., France) where a single BTV-8 serotype was dominant. Supporting this hypothesis, atmospheric dispersion modelling identified wind-transport events during July-September that could have allowed the introduction of BTV-8 infected midges from Lebanon, Syria or Israel coastlines into the Larnaca region of Cyprus.
Assuntos
Vírus Bluetongue/genética , Bluetongue/epidemiologia , Surtos de Doenças/veterinária , Genoma Viral , Animais , Bluetongue/mortalidade , Bluetongue/transmissão , Vírus Bluetongue/classificação , Vírus Bluetongue/isolamento & purificação , Bovinos/virologia , Ceratopogonidae/virologia , Chipre/epidemiologia , Feminino , Cabras/virologia , Filogenia , RNA Viral/genética , Vírus Reordenados/genética , Análise de Sequência de DNA , Sorogrupo , Ovinos/virologiaRESUMO
Bela Vista Biological Sanctuary (RBV) is a protected area of Itaipu Binacional, a hydroelectric power company located on the border of Brazil and Paraguay. A captive population of Brazilian dwarf brocket deer (Mazama nana, Cervidae, Artiodactyla) is maintained for conservation purposes. Despite the reproductive success of the animals, outbreaks of a fatal hemorrhagic disease have been registered over the years, compromising conservation efforts. In order to identify the etiological agents of these hemorrhagic diseases, 32 captive Brazilian dwarf brockets were sampled to investigate bluetongue virus (BTV), epizootic hemorrhagic disease (EHD), and adenovirus hemorrhagic disease (AHD), in 2015. Only one deer (1/32; 3.12%) was seropositive for BTV. After this survey, five animals died in the early autumn of 2015 and 2016, again presenting clinical signs of hemorrhagic disease. Using RT-qPCR, RT-PCR and DNA sequencing, five BTV serotypes (3, 14, 18, 19, and 22) were identified in blood and tissues collected during necropsies. These BTV serotypes had not been previously described or isolated in Brazil, either in wild or domestic ruminants. Additionally, differential diagnosis was performed for EHD and AHD, but all samples were negative for both diseases. The multiple distinct BTV serotypes identified in these outbreaks resulted in a high lethality (100%) of Brazilian dwarf brockets and indicated that various BTV serotypes are circulating in the area.
Assuntos
Vírus Bluetongue/imunologia , Vírus Bluetongue/patogenicidade , Bluetongue/epidemiologia , Cervos/virologia , Sorogrupo , Animais , Animais Domésticos/virologia , Bluetongue/sangue , Bluetongue/mortalidade , Bluetongue/virologia , Vírus Bluetongue/genética , Vírus Bluetongue/isolamento & purificação , Brasil/epidemiologia , Surtos de Doenças , Vírus da Doença Hemorrágica Epizoótica/genética , Vírus da Doença Hemorrágica Epizoótica/isolamento & purificação , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo RealRESUMO
During 2014, an outbreak of Bluetongue virus (BTV) infections attributed to serotype 4 occurred in Greece and spread to south-eastern Europe. In the present article, the clinical and epidemiological data of 15 sheep flocks and 5 dairy cattle herds affected in Greece are described. In sheep, the most frequent clinical signs observed were fever, hyporexia, and edema of the face. A number of clinically affected sheep had chronic laminitis resulting in chronic lameness. Confirmation of suspect clinical cases was performed using BTV-specific real-time RT-PCR, and serotype 4-specific RT-PCR. The average morbidity of bluetongue in the sheep flocks was estimated to be 15.3 % (95 % C.I. 6.8-23.8 %) and the average mortality and case fatality were 4.5 % (95 % C.I. 1.5-7.6 %) and 32.0 % (95 % C.I. 18.1-42.9 %), respectively. The BTV seroprevalence and the ratio of clinical manifestations-to-infections determined in seven of these flocks, were on average 36.5 % (95 % C.I. 15.7-57.3 %) and 24.6 % (95 % C.I. 12.8-36.3 %). BTV ratio of clinical manifestations-to-infections was higher in the imported western European sheep breeds examined compared to the local ones. In dairy cattle, the average herd prevalence of viremia was 48.8 % (95 % C.I. 15.3-82.4 %) and none had signs associated with bluetongue. The results of this study indicate that the 2014 Greek BTV-4 has significant impact on the health status and the viability of sheep in affected flocks but does not cause clinical signs in cattle, despite the high prevalence of viremia.
Assuntos
Vírus Bluetongue/isolamento & purificação , Bluetongue/epidemiologia , Surtos de Doenças/veterinária , Animais , Bluetongue/mortalidade , Bluetongue/virologia , Vírus Bluetongue/classificação , Bovinos , Feminino , Grécia/epidemiologia , Reação em Cadeia da Polimerase/veterinária , Estudos Soroepidemiológicos , OvinosRESUMO
Peste-des-petits-ruminants (PPR), bluetongue (BT) and goatpox (GP) have been well recognized as causes of significant economic losses in the small ruminant population of Asia and Africa. We describe here the occurrence of these three in an outbreak noticed in non-descript goats from a subtropical region of central India. An investigation was carried out to confirm the aetiology of the heavy mortality in goats (74.6%, 112/150), with testing of samples from 12 surviving animals exhibiting mixed clinical signs indicative of PPR, BT and GP. Sandwich ELISA was used to detect PPR virus antigen and competition ELISA to detect PPR virus and BT virus antibodies. GP was confirmed on the basis of nodular lesions and an immunodiffusion assay. Eight of the 12 affected animals (66.7%) were positive for PPR virus and BT virus antibodies, and two goats (16.7%, 2/12) exhibiting clinical lesions of pox were also found positive for PPR virus/antibodies and BT virus antibodies, respectively. Although BT virus could not be identified in any sample, detection of BT virus antibodies indicated previous or possibly concurrent infection with BT virus in these goats. The N-gene-based RT-PCR was used to confirm the PPR infection in these goats, and one of the amplicons was sequenced. The sequence and phylogenetic analysis revealed close proximity to PPR virus isolates from Tibet and China, with sequence homology of up to 96.9%. The sequence homology was relatively low with the majority of other Indian isolates (72.7-93.5%). The detection of this new PPR virus sequence indicates the circulation of cross-border strains in this region of India. It is presumed that the heavy mortality observed in goats is possibly attributable to the occurrence of mixed infection of PPR and GP, or PPR, BT and GP.
Assuntos
Anticorpos Antivirais/sangue , Bluetongue/sangue , Doenças das Cabras/sangue , Doenças das Cabras/virologia , Peste dos Pequenos Ruminantes/veterinária , Infecções por Poxviridae/veterinária , Animais , Bluetongue/mortalidade , Vírus Bluetongue/imunologia , Capripoxvirus/imunologia , Bases de Dados de Ácidos Nucleicos , Surtos de Doenças , Ensaio de Imunoadsorção Enzimática/veterinária , Doenças das Cabras/mortalidade , Cabras , Índia/epidemiologia , Peste dos Pequenos Ruminantes/sangue , Peste dos Pequenos Ruminantes/mortalidade , Vírus da Peste dos Pequenos Ruminantes/genética , Vírus da Peste dos Pequenos Ruminantes/imunologia , Infecções por Poxviridae/sangue , Infecções por Poxviridae/mortalidadeRESUMO
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 dairy industry was estimated, based on this census data. Default, mortality associated with BTV-8 was estimated for the confirmed notification herds. Moreover, an additional analysis was performed to determine if mortality associated with BTV-8 infection occurred in non-notification herds located in BTV-8 infected compartments. A multivariable population-averaged model with a log link function was used for analyses. Separate analyses were conducted for the three different age groups. Confirmed notification herds had an increased cow mortality rate ratio (MRR) (1.4 (95% CI: 1.2-1.6)); calf MRR (1.3 (95% CI: 1.1-1.4)); and newborn calf MRR (1.2 (95% CI: 1.1-1.3)). Furthermore, in non-notification herds in BTV-8 infected compartments, mortality significantly increased 1.1 times (95% CI: 1.1-1.1) in cows, 1.2 times (95% CI: 1.2-1.2) in calves and 1.1 times (1.1-1.1) in newborn calves compared with BTV-8 non-infected months. Using objective census data over a 5-year period, the MRRs indicated increased mortality associated with BTV-8 infection not only in herds of which the farmer notified clinical signs but also in non-notification herds in infected compartments.
Assuntos
Vírus Bluetongue/patogenicidade , Bluetongue/mortalidade , Doenças dos Bovinos/virologia , Bovinos/virologia , Epidemias/veterinária , Animais , Animais Recém-Nascidos/virologia , Bluetongue/virologia , Vírus Bluetongue/classificação , Doenças dos Bovinos/mortalidade , Países BaixosRESUMO
Língua azul (LA) é uma doença causada pelo vírus da língua azul (VLA) e transmitida por vetores do gênero Culicoides. Estudos sorológicos têm demonstrado a ampla presença do vírus no Brasil; entretanto, informações clínicas da LA na América do Sul são limitadas. Esse trabalho descreve alterações clínico-patológicas em ovinos acometidos pela LA no Sul do Brasil. Em dois surtos, em propriedades distintas, 15 ovinos apresentaram como principais sinais clínicos hipertermia, apatia, aumento de volume da face e região submandibular, dificuldade de deglutição com regurgitação, secreção nasal mucopurulenta esverdeada, alterações respiratórias, além de acentuada perda de peso e erosões na mucosa oral. Os achados de necropsia em seis ovinos afetados incluíram edema subcutâneo na face e região ventral do tórax, secreção nasal esverdeada, esôfago dilatado preenchido por grande quantidade de conteúdo alimentar, pulmões não colabados com áreas consolidadas anteroventrais, bem como luz da traquéia e brônquios preenchida por espuma misturada com conteúdo alimentar. No coração e base da artéria pulmonar, havia focos de hemorragia. Histologicamente, as principais alterações observadas ocorriam no tecido muscular cardíaco e esquelético, especialmente no esôfago e consistiam de lesões bifásicas caracterizadas por degeneração/necrose hialina e flocular de miofibras associadas com micro-calcificação e infiltrado inflamatório mononuclear. Pneumonia aspirativa associada à presença de material vegetal e bactérias na luz de brônquios também foi observada. O diagnóstico de LA foi confirmado pela detecção do genoma viral por duplex RT-PCR em amostras de sangue de animais afetados, seguido da identificação do VLA, sorotipo 12 por sequenciamento.
Bluetongue (BT) is a disease caused by bluetongue virus (BTV) and transmitted by vectors of the genus Culicoides. Serological studies have demonstrated the widespread presence of the virus in Brazil, however, clinical information of BT in South America are limited. This article describes clinical and pathological changes observed in sheep naturally infected by BTV in southern Brazil. In two outbreaks on different farms, 15 sheep showed clinical signs such as severe hyperthermia, apathy, swelling of the face and submandibular area, difficulty in swallowing with regurgitation, greenish mucopurulent nasal secretion, severe weight loss, and erosions in the oral mucosa. Necropsy findings in six sheep included subcutaneous edema of the face and ventral region of the chest, greenish nasal discharge, and dilated esophagus filled with abundant food contents, collapsed lungs with areas of anteroventral consolidation, and trachea and bronchi filled by foamy material mixed with food. In the heart and base of the pulmonary artery there were foci of hemorrhage. Histologically, the main changes were in cardiac and skeletal muscles and consisted of biphasic lesions characterized by hyaline and floccular degeneration/necrosis of myofibers associated with micro-mineralization and mononuclear cell infiltration. Pneumonia associated with the presence of organic matter and bacteria in the lumen of the bronchi was also observed. The diagnosis of BT was confirmed by detection of the viral genome by duplex RT-PCR in blood of affected animals, followed by the identification of BTV, serotype 12 by nucleotide sequencing.
Assuntos
Animais , Bluetongue/diagnóstico , Bluetongue/microbiologia , Bluetongue/mortalidade , Bluetongue/sangueRESUMO
On the 25th of July 2007, bluetongue virus (BTV) serotype 1 was detected in Andalusia, southern Spain for the first time. A total of 4436 farms infected with BTV-1 were confirmed during that year: 3162 in sheep flocks, 113 in goat flocks, 7 in cattle herds and 1154 in mixed farms (sheep, goat and/or cattle in the same farm). The most common clinical signs were: fever, depression, lethargy, facial edema, and salivation (observed in more than 70% of the infected farms). Lesions in oral mucosa, lameness and dyspnea were also frequently observed. Median morbidity rate in sheep and goat flocks were 6.3% and 2.7% respectively. Median mortality rate was 2.2% in sheep flocks and 1.2% in goat flocks. Median case fatality rate was 29.8% in sheep flocks and 45% in goat flocks. Morbidity and mortality rates were not significantly higher in sheep flocks than in goat flocks (p>0.05), whereas case fatality rate was significant higher in goat flocks compared to sheep flocks (p<0.05). Neither clinical signs nor mortality were observed in cattle herds. The spatial distribution of the risk of BTV infection over Andalusia by municipality was evaluated by means of a hierarchical Bayesian model. The results evidenced that the risk was not homogeneous over the territory, being higher in the western part of the region. The likelihood of BTV infection was increased between 1.01 and 1.16 times by an increase of 10,000 domestic ruminants, and between 1.01 and 1.69 times by the presence of red deer (Cervus elaphus) in the municipality.
Assuntos
Bluetongue/epidemiologia , Doenças dos Bovinos/epidemiologia , Doenças das Cabras/epidemiologia , Vigilância de Evento Sentinela/veterinária , Animais , Teorema de Bayes , Bluetongue/mortalidade , Bluetongue/virologia , Vírus Bluetongue/classificação , Bovinos , Doenças dos Bovinos/mortalidade , Doenças dos Bovinos/virologia , Demografia , Feminino , Doenças das Cabras/mortalidade , Doenças das Cabras/virologia , Cabras , Masculino , Morbidade , Fatores de Risco , Sorotipagem/veterinária , Ovinos , Espanha/epidemiologia , Especificidade da EspécieRESUMO
National Cattle Registers have been widely used to examine animal movements and their role in disease transmission, but less frequently for other epidemiological applications. Our study shows how routinely collected identification data can be used to evaluate the population impact of an epidemic in cattle and to derive an indirect estimate of the associated mortality. We adapted a method developed by Human health agencies, based on the modelling of historical mortality fluctuations, to analyze the evolution of mortality in a cattle population subjected to a Bluetongue serotype 8 (BT8) outbreak. Between 01/07/2007 and 01/07/2008, 21,017 cattle died in the considered population whereas 16,691 deaths were expected according to the model. 43% of the 4326 extra deaths were found in calves less than 7 days of age, but excess mortality was found in each age group. The temporal distribution of extra-deaths, described at a weekly scale, suggests that they were related to the BT8 epidemic. The presented method could be an appreciable tool for estimating the global burden of epidemics since it is based on data already routinely collected in each European Member State. This study was conducted retrospectively but considering the promptness of the notification system, the method could be used to monitor the evolution of epidemics in near-real time.
Assuntos
Vírus Bluetongue/isolamento & purificação , Bluetongue/mortalidade , Doenças dos Bovinos/mortalidade , Surtos de Doenças/veterinária , Sistema de Registros , Animais , Bluetongue/sangue , Bluetongue/transmissão , Bovinos , Doenças dos Bovinos/virologia , Métodos Epidemiológicos , Europa (Continente)/epidemiologia , Modelos EstatísticosRESUMO
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 in 2007 and 2006 was similar. The most prominent changes were a higher proportion of sheep flocks with lameness and a much higher proportion of cattle herds reporting a decrease in milk yield in 2007. BTV-8 associated morbidity and mortality incidence rates in sheep flocks and cattle herds were significantly (P<0.001) higher in 2007 than in 2006. Both in sheep flocks and cattle herds, BTV-8 associated case fatality was significantly (P<0.001) lower in 2007, which was probably due to better medical treatment of sick animals. There were significantly (P<0.001) more fertility problems associated with BTV-8 infection in outbreak cattle herds in 2007 compared to 2006.
Assuntos
Vírus Bluetongue/classificação , Bluetongue/epidemiologia , Doenças dos Bovinos/epidemiologia , Surtos de Doenças/veterinária , Aborto Animal , Animais , Bluetongue/mortalidade , Bluetongue/virologia , Bovinos , Doenças dos Bovinos/mortalidade , Doenças dos Bovinos/virologia , Países Baixos/epidemiologia , Reprodução , Ovinos , Fatores de TempoRESUMO
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.
Assuntos
Vírus Bluetongue , Bluetongue/epidemiologia , Doenças dos Bovinos/epidemiologia , Doenças das Cabras/epidemiologia , Doenças dos Ovinos/epidemiologia , Animais , Bluetongue/mortalidade , Bluetongue/prevenção & controle , Bluetongue/virologia , Vírus Bluetongue/classificação , Vírus Bluetongue/isolamento & purificação , Bovinos , Doenças dos Bovinos/mortalidade , Doenças dos Bovinos/prevenção & controle , Doenças dos Bovinos/virologia , Alemanha/epidemiologia , Doenças das Cabras/mortalidade , Doenças das Cabras/prevenção & controle , Doenças das Cabras/virologia , Cabras , Sorotipagem , Ovinos , Doenças dos Ovinos/mortalidade , Doenças dos Ovinos/prevenção & controle , Doenças dos Ovinos/virologia , Vacinação , Vacinas Virais/administração & dosagemAssuntos
Vírus Bluetongue/classificação , Bluetongue/virologia , Doenças dos Bovinos/virologia , Doenças dos Ovinos/virologia , Animais , Bluetongue/epidemiologia , Bluetongue/mortalidade , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/mortalidade , França/epidemiologia , Filogenia , Sorotipagem/veterinária , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/mortalidadeRESUMO
One of the most important steps when preparing a live attenuated vaccine is the assessment of the level of attenuation in target animals. It is costly and time consuming as it requires, on each occasion, a large number of susceptible animals and contained accommodation. This study assessed the consistency of the bovine foetal aorta endothelial (BFA) cell line and newborn mice for evaluating the attenuation level of BTV4, BTV9 and BTV16 Italian field isolates. Following serial passages in BHK(21c13) or Vero cell cultures, BTV attenuated clones demonstrated a reduced replication capability in the BFA cells compared to the homologous virulent strains. Similarly, following intracerebral inoculation, the attenuated clones were completely innocuous to newborn mice contrary to the homologous virulent strains which killed all animals within 10 days. Vaccines produced with the BTV9 or BTV4 attenuated clones were safe, immunogenic and capable of preventing clinical symptoms and viraemia in sheep following challenge with homologous virulent virus. The two assays may be valuable indicators of the gradual changes occurring in the BTV population leading to virus attenuation, they can predict the safety of a BTV attenuated vaccine and, in turn, reduce the number of sheep and cattle required to assess the level of attenuation attained.
Assuntos
Vírus Bluetongue/patogenicidade , Bluetongue/prevenção & controle , Células Endoteliais/virologia , Vacinas Atenuadas , Vacinas Virais , Animais , Animais Recém-Nascidos , Aorta/citologia , Bluetongue/mortalidade , Bluetongue/virologia , Vírus Bluetongue/fisiologia , Linhagem Celular , Chlorocebus aethiops , Cricetinae , Embrião de Mamíferos , Camundongos , Ovinos , Doenças dos Ovinos/mortalidade , Doenças dos Ovinos/prevenção & controle , Doenças dos Ovinos/virologia , Vacinas Atenuadas/administração & dosagem , Células Vero , Vacinas Virais/administração & dosagem , Virulência , Replicação ViralRESUMO
Data collected in the Netherlands during the Bluetongue serotype 8 (BTV-8) epidemic indicated that in outbreak cattle herds, predominantly dairy and nursing cows were clinically affected and not young stock, beef cattle, beef calves, or breeding animals. In outbreak sheep flocks, mainly ewes and--if present--rams, were clinically affected and not the lambs. Median morbidity rate in outbreak herds was 1.85 per 100 sheep-month at risk and 0.32 per 100 cattle-month at risk for sheep and cattle, respectively. The mean proportion of BT-affected animals in outbreak herds that recovered from clinical disease was approximately eight times higher for cattle compared to sheep in the Netherlands. Median mortality rate in outbreak herds was 0.5 per 100 sheep-month at risk of dying and 0 per 100 cattle-month at risk of dying for sheep and cattle, respectively. Median recovery time of both sheep and cattle that recovered from clinical disease in outbreak herds was 14 days. Median case fatality was 50% in sheep outbreak flocks and 0% in outbreak cattle herds. It is concluded that morbidity and mortality in outbreak cattle herds was very limited during the BTV-8 epidemic in the Netherlands in 2006. In outbreak sheep flocks, morbidity was limited, with exceptions for a few flocks. However, almost 50% of the clinically sick sheep died in outbreak sheep herds.
Assuntos
Vírus Bluetongue/isolamento & purificação , Bluetongue/mortalidade , Bluetongue/virologia , Doenças dos Bovinos/mortalidade , Doenças dos Bovinos/virologia , Surtos de Doenças/veterinária , Animais , Bluetongue/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Feminino , Modelos Logísticos , Masculino , Morbidade , Países Baixos/epidemiologia , Ovinos , Inquéritos e QuestionáriosRESUMO
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 first clinical signs by the owner and reporting of a clinically suspect BT situation to the veterinary authorities was approximately 2 weeks. BTV-8-associated clinical signs were more prominent in sheep than in cattle, and the relative frequency of specific clinical signs was different in cattle and sheep. Morbidity and mortality rates were significantly higher among sheep than among cattle, and a higher proportion of cattle than sheep recovered from clinical disease.
Assuntos
Vírus Bluetongue/isolamento & purificação , Bluetongue/epidemiologia , Bluetongue/mortalidade , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/mortalidade , Animais , Bluetongue/patologia , Vírus Bluetongue/classificação , Bovinos , Doenças dos Bovinos/patologia , Surtos de Doenças/veterinária , Feminino , Masculino , Países Baixos/epidemiologia , Sorotipagem/veterinária , Ovinos , Especificidade da EspécieRESUMO
Since 2006 bluetongue disease is rapidly spreading across Europe and reached Switzerland in October 2007. In the present article a short overview about the disease and the virus is given, and the first three clinical bluetongue disease cases in cattle, and the respective laboratory findings are presented.
Assuntos
Vírus Bluetongue/isolamento & purificação , Bluetongue/epidemiologia , Doenças dos Bovinos/epidemiologia , Animais , Bluetongue/diagnóstico , Bluetongue/mortalidade , Bluetongue/patologia , Bovinos , Doenças dos Bovinos/diagnóstico , Doenças dos Bovinos/patologia , Doenças dos Bovinos/virologia , Ensaio de Imunoadsorção Enzimática , Feminino , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Suíça/epidemiologiaAssuntos
Vírus Bluetongue/patogenicidade , Bluetongue/epidemiologia , Doenças dos Bovinos/epidemiologia , Surtos de Doenças/veterinária , Animais , Bluetongue/mortalidade , Bluetongue/patologia , Bluetongue/prevenção & controle , Vírus Bluetongue/isolamento & purificação , Bovinos , Doenças dos Bovinos/mortalidade , Doenças dos Bovinos/patologia , Doenças dos Bovinos/prevenção & controle , Feminino , Política de Saúde , Vigilância da População , Reino Unido/epidemiologiaRESUMO
For the first time Bluetongue (BT) has been diagnosed in the Netherlands. The clinical symptoms of BT on five farms during the first outbreak ever in the Netherlands are described. Fever and swollen sensitive coronets leading to reluctance to stand and walk were sometimes the first symptoms. Later lesions in the mouth occurred with foamy salivation and respiratory problems. In other cases a swollen head with swollen lips and foamy salivation were the first clinical signs. Also sudden death occurred. In the first sixteen confirmed cases morbidity and mortality were lower than described in outbreaks in other countries. Good collaboration between practitioners, specialists of the Animal Health Service (GD-Deventer), and specialists of the Food and Consumer Product Safety Authority (VWA) and CIDC-Lelystad (Wageningen UR) led to a rapid notification and ultimately confirmation of the suspected diagnosis BT.