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Bluetongue (BT) is a vector-borne disease affecting wild and domestic ruminants in many parts of the world. Although bluetongue virus (BTV) is widespread in ungulates in Africa, available epidemiological information on BT in this continent is limited. This systematic review and meta-analysis aimed to estimate the seroprevalence of BTV and summarize information on associated risk factors in domestic ruminants and camels in Africa. Systematic searches were conducted from the inception of the database to November 2022 on PubMed/MEDLINE, ScienceDirect, Web of Science, and Google/Google Scholar. Forty-four eligible publications were identified, published in the range from 1973 to 2020, and statistically analyzed. The pooled overall seroprevalence of BTV was 45.02% (95% confidence interval [CI]: 36.00-54.00%). The pooled seroprevalence was 49.70% (95% CI: 34.50-65.00%) in cattle, 47.00% (95% CI: 29.90-64.50%) in goats, 40.80% (95% CI: 19.60-63.90%) in camels, and 36.30% (95% CI: 29.00-44.90%) in sheep. The pooled seroprevalence decreased after 1990 and increased again after 2010. The highest pooled overall seroprevalence was found in the southeastern region, and the highest pooled overall seroprevalence was obtained by Competitive Enzyme-Linked Immunosorbent Assay. Finally, the seroprevalence in females (53.30%, 95% CI: 34.80-71.00%) was significantly higher than in males (28.10%, 95% CI: 17.40-40.30%) ( p  < 0.05). We showed that antibodies against BTV were common in African ruminants and camels. Monitoring the seroprevalence of BTV, as well as systematic and continuous surveillance of the Culicoides population, are encouraged to prevent and control the spread of BT.

Since 1998, notifiable bluetongue virus (BTV) serotypes 1-4, 6, 8, 9, 11, and 16 have been reported in Europe. In August 2006, a bluetongue (BT) outbreak caused by BTV serotype 8 began in northwestern Europe. The Netherlands was declared BT-free in February 2012, and annual monitoring continued. On September 3, 2023, typical BT clinical manifestations in sheep were notified to the Netherlands Food and Product Safety Consumer Authority. On September 6, we confirmed BTV infection through laboratory diagnosis; notifications of clinical signs in cattle were also reported. We determined the virus was serotype 3 by whole-genome sequencing. Retrospective analysis did not reveal BTV circulation earlier than September. The virus source and introduction route into the Netherlands remains unknown. Continuous monitoring and molecular diagnostic testing of livestock will be needed to determine virus spread, and new prevention strategies will be required to prevent BTV circulation within the Netherlands and Europe.

In October 2023, bluetongue virus serotype 3 (BTV-3) emerged in Germany, where Schmallenberg virus is enzootic. We detected BTV-3 in 1 pool of Culicoides biting midges collected at the time ruminant infections were reported. Schmallenberg virus was found in many vector pools. Vector trapping and analysis could elucidate viral spread.

The serological surveillance of bluetongue in bulk tank milk is an efficient and cost-effective method for the early detection of bluetongue virus incursions in unvaccinated free areas of the disease. In addition, the availability of standardized and reliable reagents and refined diagnostic procedures with high sensitivity and specificity are essential for surveillance purposes. However, no available reference materials for bluetongue virus serological surveillance in bulk tank milk exist. This study shows the production and characterization of reference material for the implementation of a commercially available bluetongue milk ELISA test in official laboratories, as well as the evaluation of a procedure to increase the sensitivity in samples with low levels of antibodies. This procedure, based on milk protein concentration, allowed us to notably increase the ELISA test's analytical sensitivity, which is useful for milk samples from farms with low within-herd prevalence or pools of bulk tank milk samples. The standardized milk reference material produced here, together with the evaluated procedure to improve analytical sensitivity, could be applied as tools to ensure an accurate diagnosis by official laboratories in bluetongue unvaccinated free areas.

Culicoides spp. (Diptera: Ceratopogonidae) are small biting midges, some of which are the vectors of arboviruses affecting livestock, i.e., African horse sickness virus (AHSV), bluetongue virus (BTV), and epizootic hemorrhagic disease virus (EHDV). Yunnan Province, located in southwestern China, has a history of high prevalence of arboviruses. The diversity and abundance of Culicoides was observed between March 2022 and March 2023 on two cattle farms in Lufeng County of Yunnan Province, China and virus isolation and PCR detection were attempted from cattle blood and Culicoides spp. collected from the farms. Light trap collections contained 19 species of Culicoides belonging to 8 subgenera and one unplaced species group and were dominated by C. oxystoma (63.4%), C. imicola (16.2%), C. arakawae (13.4%), C. sp. near newsteadi (2.3%), and C. orientalis (1.7%). A total of 8,343 Culicoides were used for statistical analysis; from these collections 997 Culicoides specimens belonging to 10 species were screened for the presence of BTV, EHDV, Yunnan Orbivirus (YUOV), and Yongshan totivirus (YSToV) using reverse transcription quantitative PCR (RT-qPCR). One strain of YUOV was isolated from cattle blood and 7 isolates of YSToV were isolated from 5 different species of Culicoides. BTV and YSToV were detected from 2 and 3 pools of parous C. imicola specimens by RT-qPCR, respectively, which is the first report of a totivirus to be associated with Culicoides. Culicoides imicola is likely to be the major vector of Culicoides-borne arboviruses in Lufeng County, which is a relatively dry locality, and adult C. imicola may play a role of BTV overwintering., (© Y.-L. Duan et al., published by EDP Sciences, 2024.)

Bluetongue (BT) is an insect-borne, non-contagious viral disease which affects domestic ruminants including camels and is transmitted by Culicoides spp. Clinical symptoms of BT are typically seen in sheep, although subclinical BT infections are mostly seen in cattle, goats, and camelids. The goal of the present study was to evaluate the sero-prevalence of Bluetongue virus (BTV) in camels from some governorates in Egypt's southern and northern regions, as well as the infection's potential risk factors. During 2020-2021, a cross sectional study was conducted to screen presence of anti-BTV antibodies in 400 serum samples, which were collected randomly from camels, examined using competitive enzyme-linked immunosorbent assay (cELISA). The sera of 102 out of 400 camels tested positive for BTV, representing a frequency of 25.5%. Moreover, the odds of sero-positivity were higher among camels living in Aswan (OR = 5.33, 95%CI: 2.35-12.11), especially in females (OR = 2.63, 95%CI = 1.44-4.09) during summer season (OR = 2.40, 95%CI = 1.20-4.81). Furthermore, the probability of getting BTV infection increased when camels were exposed to the insect vectors (OR = 1.63, 95%CI = 0.87-3.09). The high prevalence of BTV in camels in several Egyptian regions highlights the need for more epidemiological investigations of BTV infection in other ruminant species in order to better control BT disease in these regions., (© 2022. The Author(s).)

In this article, we describe the development and evaluation of a double antigen sandwich enzyme-linked immunosorbent assay (ELISA) able to detect serotype 4-specific antibodies from BTV-4 infected or vaccinated animals using a recombinant BTV-4 VP2 protein. The coding sequence of VP2 was inserted into a pVote plasmid by recombination in the Gateway ® cloning system. Vaccinia virus (VacV) was used as a vector for the expression of the recombinant VP2. After production in BSR cells, recombinant VP2 was purified by immunoprecipitation using a FLAG tag and then used both as the coated ELISA antigen and as the HRP-tagged conjugate. The performance of the ELISA was evaluated with 1186 samples collected from BTV negative, infected or vaccinated animals. The specificity and sensitivity of the BTV-4 ELISA were above the expected standards for the detection of anti-BTV-4 VP2 antibodies in animals reared in Europe or in the Mediterranean basin. Cross-reactions were observed with reference sera for serotypes 10 and 20, and to a lesser extent with serotypes 12, 17 and 24, due to their genetic proximity to serotype 4. Nevertheless, these serotypes have never been detected in Europe and the Mediterranean area. This ELISA, which requires only the production of a recombinant protein, can be used to detect BTV serotype 4-specific antibodies and is therefore an attractive alternative diagnostic method to serum neutralization.

Arboviruses such as bluetongue virus (BTV) replicate in arthropod vectors involved in their transmission between susceptible vertebrate-hosts. The "classical" BTV strains infect and replicate effectively in cells of their insect-vectors ( Culicoides biting-midges), as well as in those of their mammalian-hosts (ruminants). However, in the last decade, some "atypical" BTV strains, belonging to additional serotypes (e.g., BTV-26), have been found to replicate efficiently only in mammalian cells, while their replication is severely restricted in Culicoides cells. Importantly, there is evidence that these atypical BTV are transmitted by direct-contact between their mammalian hosts. Here, the viral determinants and mechanisms restricting viral replication in Culicoides were investigated using a classical BTV-1, an "atypical" BTV-26 and a BTV-1/BTV-26 reassortant virus, derived by reverse genetics. Viruses containing the capsid of BTV-26 showed a reduced ability to attach to Culicoides cells, blocking early steps of the replication cycle, while attachment and replication in mammalian cells was not restricted. The replication of BTV-26 was also severely reduced in other arthropod cells, derived from mosquitoes or ticks. The data presented identifies mechanisms and potential barriers to infection and transmission by the newly emerged "atypical" BTV strains in Culicoides .

Transmission of bluetongue (BT) virus serotype 8 (BTV-8) via artificial insemination of contaminated frozen semen from naturally infected bulls was investigated in two independent experiments. Healthy, BT negative heifers were hormonally synchronized and artificially inseminated at oestrus. In total, six groups of three heifers received semen from four batches derived from three bulls naturally infected with BTV-8. Each experiment included one control heifer that was not inseminated and that remained BT negative throughout. BTV viraemia and seroconversion were determined in 8 out of 18 inseminated heifers, and BTV was isolated from five of these animals. These eight heifers only displayed mild clinical signs of BT, if any at all, but six of them experienced pregnancy loss between weeks four and eight of gestation, and five of them became BT PCR and antibody positive. The other two infected heifers gave birth at term to two healthy and BT negative calves. The BT viral load varied among the semen batches used and this had a significant impact on the infection rate, the time of onset of viraemia post artificial insemination, and the gestational stage at which pregnancy loss occurred. These results, which confirm unusual features of BTV-8 infection, should not be extrapolated to infection with other BTV strains without thorough evaluation. This study also adds weight to the hypothesis that the re-emergence of BTV-8 in France in 2015 may be attributable to the use of contaminated bovine semen.

Hemorrhagic disease (HD) is considered one of the most significant infectious diseases of white-tailed deer in North America. Investigations into environmental conditions associated with outbreaks suggest drought conditions are strongly correlated with outbreaks in some regions of the United States. However, during 2017, an HD outbreak occurred in the Eastern United States which appeared to be associated with a specific physiographic region, the Appalachian Plateau, and not drought conditions. The objective of this study was to determine if reported HD in white-tailed deer in 2017 was correlated with physiographic region. There were 456 reports of HD from 1605 counties across 26 states and 12 physiographic regions. Of the 93 HD reports confirmed by virus isolation, 76.3% (71/93) were identified as EHDV-2 and 66.2% (47/71) were from the Appalachian Plateau. A report of HD was 4.4 times more likely to occur in the Appalachian Plateau than not in 2017. Autologistic regression models suggested a statistically significant spatial dependence. The underlying factors explaining this correlation are unknown, but may be related to a variety of host, vector, or environmental factors. This unique outbreak and its implications for HD epidemiology highlight the importance for increased surveillance and reporting efforts in the future.

Bluetongue (BT) is an insect-borne disease affecting domestic and wild ruminants. Bluetongue virus (BTV) is the causative agent of the BT disease. BT outbreaks have been widely recorded worldwide. However, in the South American subcontinent, accurate information about the disease and molecular epidemiology is still lacking because little effort has been made to cover the region. This study comprises an exhaustive phylogenetic analysis including all BTV sequences available in databases and reports new Argentinean sequences for Seg 8 and Seg 9. Maximum-likelihood phylogenetic analyses were conducted for Seg 2, Seg 3, Seg 6, Seg 7, Seg 8, Seg 9 and Seg 10. Throughout the study, wide circulation and genetic continuity along the American continent were detected. Also, reassortment events are reported, and the historical virus introduction path into and through South America is suggested.

Bluetongue virus (BTV) is an arbovirus (genus: Orbivirus ) that occurs worldwide. It infects domestic and wild ruminant species and can cause disease in livestock, producing high economic impact. Recently, it gained extra prominence throughout Europe, with disease occurring in regions traditionally free of BTV. BTV enters Australia from Southeast Asia via wind-borne infected Culicoides spp. The first Australian isolation was 1975 (BTV-20) and further serotypes were isolated between 1979-86 (BTV-1, -3, -9, -15, -16, -21, -23). Despite increased, more sensitive, monitoring, no more were detected in over two decades, implying a stable BTV episystem of eastern ancestry. Isolations of BTV-2, -7 and -5 then occurred between 2007-15, with the latter two possessing genome segments with high sequence identity to western isolates. We report on the first isolation and genomic characterization of BTV-12, which revealed that three more novel western topotype gene segments have entered northern Australia.

Background: Culicoides (Diptera: Ceratopogonidae) are vectors for many arboviruses. At least 20 species are considered as vectors or potential vectors of bluetongue virus (BTV) which cause bluetongue disease in ruminants. A BTV prevalence of 30-50% among cattle and goats in tropical southern Yunnan Province, China, prompted an investigation of the potential BTV vectors in this area., Methods: Culicoides were collected by light trapping at three sites in the tropical region of Yunnan Province. Species were identified based on morphology and DNA sequences of cytochrome c oxidase subunit 1 (cox1). PCR and quantitative PCR following reverse transcription were used to test for the presence of BTV RNA in these specimens. Phylogenetic analysis was used to analyze the cox1 sequences of Culicoides specimens infected with BTV., Results: Approximately 67,000 specimens of Culicoides were collected, of which 748 were tested for the presence of BTV. Five specimens, including two of Culicoides jacobsoni, one of C. tainanus and two of C. imicola, were identified as infected with BTV. No specimens of C. (subgenus Trithecoides) or C. oxystoma tested were positive for BTV infection., Conclusions: To our knowledge this is the first report of C. jacobsoni as a potential BTV vector and the fourth report of an association between C. tainanus and BTV, as well as the first direct evidence of an association between BTV and C. imicola in Asia. A fourth potential cryptic species within C. tainanus was identified in this study. Further analysis is required to confirm the importance of C. jacobsoni and C. tainanus in BTV epidemiology in Asia.

A wild population of white-tailed deer (Odocoileus virginianus) was surveyed for evidence of past or current epizootic hemorrhagic disease virus (EHDV) and current bluetongue virus (BTV) infections. We collected 121 blood samples from hunter-harvested or live-captured deer from two state-managed properties in northwest Florida, US; live captures were in support of a movement ecology study. Blood samples were tested for antibodies against titers to three EHDV serotypes (EHDV-1, EHDV-2, and EHDV-6), and multiplex quantitative reverse transcription PCR was used to identify the presence of EHDV or BTV viral RNA. Of these samples, 81% (98/121) tested seropositive for at least one of three serotypes of EHDV. Of those testing seropositive, 33% (40/121) contained antibodies for two serotypes, and 19% (24/121) contained antibodies for all three EHDV serotypes. Furthermore, results of generalized linear models indicated that the probability of infection by EHDV serotypes 1 and 6 increased with an animal's age. Our findings indicate that seroprevalence may be high for multiple serotypes in regions where these orbiviruses are endemic. These results could prove useful for managing disease risk in naïve deer populations., (© Wildlife Disease Association 2020.)

We investigate the restriction of animal movements as a method to control the spread of bluetongue, an infectious disease of livestock that is becoming increasingly prevalent due to the onset of climate change. We derive control policies for the UK that minimise the number of infected farms during an outbreak using Bayesian optimisation and a simulation-based model of BT. Two cases are presented: first, where the region of introduction is randomly selected from England and Wales to find a generalised strategy. This "national" model is shown to be just as effective at subduing the spread of bluetongue as the current strategy of the UK government. Our proposed controls are simpler to implement, affect fewer farms in the process and, in so doing, minimise the potential economic implications. Second, we consider policies that are tailored to the specific region in which the first infection was detected. Seven different regions in the UK were explored and improvements in efficiency from the use of specialised policies presented. As a consequence of the increasing temperatures associated with climate change, efficient control measures for vector-borne diseases such as this are expected to become increasingly important. Our work demonstrates the potential value of using Bayesian optimisation in developing cost-effective disease management strategies.

Recently, several so-called "atypical" Bluetongue virus (BTV) serotypes were discovered, including BTV-25 (Toggenburg virus), in Switzerland. Most "atypical" BTV were identified in small ruminants without clinical signs. In 2018, two goats from a holding in Germany tested positive for BTV-25 genome by RT-qPCR prior to export. After experimental inoculation of the two goats with the BTV-25 positive field blood samples for generation of reference materials, viremia could be observed in one animal. For the first time, the BTV-25-related virus was isolated in cell culture from EDTA-blood and the full genome of isolate "BTV-25-GER2018" could be generated. BTV-25-GER2018 was only incompletely neutralized by ELISA-positive sera. We could monitor the BTV-25 occurrence in the respective affected goat flock of approximately 120 goats over several years. EDTA blood samples were screened with RT-qPCR using a newly developed BTV-25 specific assay. For serological surveillance, serum samples were screened using a commercial cELISA. BTV-25-GER2018 was detected over 4.5 years in the goat flock with intermittent PCR-positivity in some animals, and with or without concomitantly detected antibodies since 2015. We could demonstrate the viral persistence of BTV-25-GER2018 in goats for up to 4.5 years, and the first BTV-25 isolate is now available for further characterization.

Bluetongue (BT) is an arthropod-borne viral disease of ruminants with serious trade and socio-economic implications. Although the disease has been reported in a number of countries in sub-Saharan Africa, there is currently no information on circulating serotypes and disease distribution in Zambia. Following surveillance for BT in domestic and wild ruminants in Zambia, BT virus (BTV) nucleic acid and antibodies were detected in eight of the 10 provinces of the country. About 40% (87/215) of pooled blood samples from cattle and goats were positive for BTV nucleic acid, while one hartebeest pool (1/43) was positive among wildlife samples. Sequence analysis of segment 2 revealed presence of serotypes 3, 5, 7, 12 and 15, with five nucleotypes (B, E, F, G and J) being identified. Segment 10 phylogeny showed Zambian BTV sequences clustering with Western topotype strains from South Africa, intimating likely transboundary spread of BTV in Southern Africa. Interestingly, two Zambian viruses and one isolate from Israel formed a novel clade, which we designated as Western topotype 4. The high seroprevalence (96.2%) in cattle from Lusaka and Central provinces and co-circulation of multiple serotypes showed that BT is widespread, underscoring the need for prevention and control strategies.

Peste des petits ruminants (PPR) disease was first confirmed in Tanzania in 2008 in sheep and goats in Ngorongoro District, northern Tanzania, and is now endemic in this area. This study aimed to characterise PPR disease in pastoralist small ruminant flocks in Ngorongoro District. During June 2015, 33 PPR-like disease reports were investigated in different parts of the district, using semi-structured interviews, clinical examinations, PPR virus rapid detection test (PPRV-RDT), and laboratory analysis. Ten flocks were confirmed as PPRV infected by PPRV-RDT and/or real-time reverse transcription-polymerase chain reaction (RT-qPCR), and two flocks were co-infected with bluetongue virus (BTV), confirmed by RT-qPCR. Phylogenetic analysis of six partial N gene sequences showed that the PPR viruses clustered with recent lineage III Tanzanian viruses, and grouped with Ugandan, Kenyan and Democratic Republic of Congo isolates. No PPR-like disease was reported in wildlife. There was considerable variation in clinical syndromes between flocks: some showed a full range of PPR signs, while others were predominantly respiratory, diarrhoea, or oro-nasal syndromes, which were associated with different local disease names ( olodua- a term for rinderpest, olkipiei -lung disease, oloirobi -fever, enkorotik -diarrhoea). BTV co-infection was associated with severe oro-nasal lesions. This clinical variability makes the field diagnosis of PPR challenging, highlighting the importance of access to pen-side antigen tests and multiplex assays to support improved surveillance and targeting of control activities for PPR eradication.

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., Competing Interests: The authors declare no conflict of interest.

We determined the temporal aspects of detecting bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) in postmortem bone marrow samples of white-tailed deer ( Odocoileus virginianus ) using molecular and in vitro cell culture techniques. Bone marrow samples from carcasses were collected and assayed on the day of death and at intervals up to 16 wk after death. We recovered BTV and EHDV from fresh bone marrow collected at day 0 by isolation in Vero and BHK-21 cell cultures. However, attempts to replicate the viruses from aged bone marrow in Vero and BHK-21 cell cultures failed. The real-time quantitative reverse transcriptase PCR (qRT-PCR) results confirmed that EHDV and BTV can be detected in aged bone marrow for up to 12 and 16 wk, respectively, after death. The RNA of BTV and EHDV could be detected by qRT-PCR in white-tailed deer bone marrow for extended periods of time postmortem. This technique will provide a useful tool for retrospective determination of BTV or EHDV infection of white-tailed deer at the time of death.

Background: Bluetongue virus (BTV), an emerging insect vector mediated pathogen affecting both wild ruminants and livestock, has a genome consisting of 10 linear double-stranded RNA genome segments. BTV has a severe economic impact on agriculture in many parts of the world. Current reverse genetics (RG) strategy to rescue BTV mainly rely on in vitro synthesis of RNA transcripts from cloned complimentary DNA (cDNA) corresponding to viral genome segments with the aid of helper plasmids. RNA synthesis is a laborious job which is further complicated with a need for expensive reagents and a meticulous operational procedure. Additionally, the target genes must be cloned into a specific vector to prepare templates for RNA transcription., Result: In this study, we have developed a PCR based BTV RG system with easy two-step transfection. Viable viruses were recovered following a first transfection with the seven helper plasmids and a second transfection with the 10 PCR products on the BSR cells. Further, recovered viruses were characterized with indirect immunofluorescence assays (IFA) and gene sequencing. And the proliferation properties of these viruses were also compared with wild type BTV. Interestingly, we have identified that viruses containing the segment 2 of the genome from reassortant BTV, grew slightly slower than the others., Conclusion: In this study, a convenient PCR based RG platform for BTV is established, and this strategy could be an effective alternative to the original available BTV rescue methods. Furthermore, this RG strategy is likely applicable for other Orbiviruses.

Background: Bluetongue disease of ruminants is a typical insect-borne disease caused by bluetongue virus (BTV) of the genus Orbivirus (family Reoviridae) and transmitted by some species of Culicoides (Diptera: Ceratopogonidae). Recently, the detection of BTV in yaks in high altitude meadows of the Shangri-La district of Yunnan Province, China, prompted an investigation of the Culicoides fauna as potential vectors of BTV., Methods: A total of 806 Culicoides midges were collected by light trapping at three sites at altitudes ranging from 1800 to 3300 m. The species were identified based on morphology and the DNA sequences of cytochrome c oxidase subunit 1 (cox1). PCR and quantitative PCR following reverse transcription were used to test for the presence of BTV RNA in Culicoides spp. A phylogenetic analysis was used to analyze the cox1 sequences of some specimens., Results: Four species dominated these collections and cox1 barcoding revealed that at least two of these appear to belong to species new to science. Culicoides tainanus and a cryptic species morphologically similar to C. tainanus dominated low altitude valley collections while C. nielamensis was the most abundant species in the high-altitude meadow. A species related to C. obsoletus occurred at all altitudes but did not dominate any of the collections. BTV RT-qPCR analysis detected BTV RNA in two specimens of C. tainanus, in one specimen closely related to C. tainanus and in one specimen closely related to C. obsoletus by barcode sequencing., Conclusions: This study suggests that BTV in high altitude areas of Yunnan is being transmitted by three species of Culicoides, two of which appear to be new to science. This research may be useful in improving understanding of the effects of global warming on arboviral disease epidemiology and further study is important in research into disease control and prevention.

Background: Bluetongue is a vector-borne viral disease, and bluetongue virus (BTV) outbreaks can cause substantial economic losses. Even subclinical infection may carry significant associated costs, including a loss of condition, reduced milk yield, and infertility and abortion, and indirect costs, largely due to the export restrictions and surveillance requirements imposed to limit the spread of the virus. However, the BTV epidemiology in the Far East remains incompletely understood, especially in the cattle population in South Korea. In this study, the seroprevalence of BTV antibodies and distribution of BTV serotypes in dairy cattle in South Korea were evaluated to improve the understanding of the BTV epidemiological situation in the Asia-Pacific region., Results: Between 2012 and 2013, a total of 37 out of 171 dairy cattle herds (21.6%) and 85 out of 466 dairy cattle heads (18.2%) showed antibodies against BTV. Neutralizing antibodies to BTV-1, - 2, - 3, - 4, - 7, - 15, and - 16 serotypes were identified, and the RNAs of the BTV-1, - 2, - 3, - 15, and - 16 serotypes were detected, indicating that BTV was circulating in the dairy cattle population in South Korea., Conclusions: These findings indicate that BTV is widespread and has circulated in dairy cattle in South Korea. This is the first report presenting evidence of circulating antibodies against BTV and the serotype distribution in bovine populations in South Korea.

Bluetongue virus (BTV), transmitted by midges (Culicoides sp), is distributed worldwide and causes disease in ruminants. In particular, BT can be a debilitating disease in sheep causing serious trade and socio-economic consequences at both local and global levels. Across Australia, a sentinel cattle herd surveillance program monitors the BTV activity. Prior to 2014, BTV-1, -2, -3, -7, -9, -15, -16, -20, -21 and -23 had been isolated in Australia, but no bluetongue disease has occurred in a commercial Australian flock. We routinely use a combination of serology, virus isolation, RT-PCR and next generation and conventional nucleotide sequencing technologies to detect and phylogenetically characterize incursions of novel BTV strains into Australia. Screening of Northern Territory virus isolates in 2015 revealed BTV-5, a serotype new to Australia. We derived the complete genome of this isolate and determined its phylogenetic relationship with exotic BTV-5 isolates. Gene segments 2, 6, 7 and 10 exhibited a close relationship with the South African prototype isolate RSArrrr/5. This was the first Australian isolation of a Western topotype of segment 10. Serological surveillance data highlighted the antigenic cross-reactivity between BTV-5 and BTV-9. Phylogenetic investigation of segments 2 and 6 of these serotypes confirmed their unconventional relationships within the BTV serogroup. Our results further highlighted a need for a revision of the current serologically based system for BTV strain differentiation and importantly, implied a potential for genome segments of pathogenic Western BTV strains to rapidly enter Southeast Asia. This emphasized a need for continued high-level surveillance of vectors and viruses at strategic locations in the north of Australia The expansion of routine characterization and classification of BTV to a whole genome approach is recommended, to better monitor the presence and level of establishment of novel Western topotype segments within the Australian episystem., (© 2019 The Authors. Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

Bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) have both been reported in mainland Ecuador, but their occurrence was unknown in the Galapagos Islands, an Ecuadorian province. We aimed to detect BTV or EHDV in cattle from the 3 main cattle-producing Galapagos Islands at a between-herd design prevalence of 20% and a within-herd design prevalence of 15%. Blood samples were collected from 410 cattle in 33 farms and tested for antibodies against BTV and EHDV by competitive ELISAs. All results were negative, suggesting that BTV and EHDV are not present in the Galapagos Islands.

A  serosurvey  was  conducted  to  determine  the  value  of  camels  (Camelus  dromedaries)  as sentinel animals for the detection of bluetongue virus (BTV) in Morocco. Between 2010 and 2013, camels from various localities in Morocco were randomly tested for antibodies against BTV  serotypes‑1,  ‑4,  ‑6,  ‑8,  ‑11,  ‑14,  and  ‑16.  Antibodies  against  1  or  more  serotypes  were detected in 41.8% of 537 camels tested with a competitive enzyme‑linked immunosorbent assay  (ELISA)  diagnostic  test.  Of  the  7  tested  serotypes,  only  BTV‑11  antibodies  were  not detected with serum neutralisation assays. This study not only confirms the epidemiological presence of BTV‑1, ‑4, and ‑8 in Morocco, but also presents the first evidence of BTV‑6, ‑14, and ‑16 in the country. As such, we conclude that camels would be ideal sentinel animals to determine the potential risk of BTV in Morocco.

A population of white-tailed deer ( Odocoileus virginianus) resides throughout the island of St. John, US Virgin Islands, predominately in the Virgin Islands National Park. Adult deer ( n=23), ranging from 1 yr to 8 yr old, were assessed to characterize body condition and health. Serologic samples were screened for important viral pathogens in the area, including Zika, chikungunya, bluetongue, and epizootic hemorrhagic disease viruses. Samples were collected in July 2016; males were in velvet and all females were in diestrus. Deer had recovered from a severe drought the previous year but were generally healthy, with a low-level but high incidence of tick parasitism. Marked statistically significant changes in hematocrit and hemoglobin levels were associated with the effects of the anesthetic mixture used for capture. No other statistically significant differences were observed. Serum from four deer induced reduction in Zika virus plaques, suggesting possible exposure. No serum was reactive for chikungunya virus. Bluetongue and epizootic hemorrhagic disease antibodies were present in 50% of the sampled deer, but no clinical signs associated with disease were observed during the study period. These data will be valuable for future dynamic health assessment and may help assess changes to the population, such as those induced by climate change, infectious disease, or other demographic events.

Background: Culicoides biting midges (Diptera: Ceratopogonidae) are responsible for the biological transmission of arboviruses of international importance between ruminant livestock. These arboviruses include bluetongue virus (BTV) and Schmallenberg virus (SBV), which have emerged in unprecedented outbreaks in northern Europe. The impact of breed and shearing of sheep on Culicoides: host contact rates has not been investigated in detail and has the potential to influence arbovirus transmission and control measures employed to limit spread., Methods: Attraction of Culicoides to Hartline and Hartline/Suffolk cross-breed sheep was compared using 224 drop trap collections over 22 nights and 181 catches from sheared or unsheared Hartline/Suffolk ewes were made over 17 nights to compare Culicoides activity and rates of blood engorgement., Results: A total of 31,314 Culicoides was collected in the two trials and females of the subgenus Avaritia represented over 96.9% of individuals collected. Attraction to breed was dependent upon species of Culicoides and physiological status, with a significantly greater number of individuals collected on the cross-breed sheep. Shearing of sheep did not significantly increase or decrease the number of Culicoides attracted but increased the rate of successful engorgement., Conclusions: Both breed and shearing were shown to influence Culicoides biting rate on sheep. These data are useful in a direct context in understanding the likely impact of control measures against arboviruses including BTV and SBV and additionally in providing data from field-based studies to enable modelling exercises of arbovirus transmission and spread.

Background: Following the emergence of Schmallenberg virus (SBV) in Ireland in 2012, a sentinel herd surveillance program was established in the south of Ireland with the primary aim of investigating the species composition and abundance of Culicoides on livestock farms in the region., Methods: Ultraviolet-light trapping for Culicoides was carried out on 10 sentinel farms. Each site was sampled fortnightly over 16 weeks (21st July to 5th November 2014). One Onderstepoort Veterinary Institute UV light trap was run overnight at each site and catches were transferred immediately into 70% ethanol. Culicoides were morphologically identified to species level. Collection site habitats were characterised using the Phase 1 habitat survey technique (Joint Nature Conservation Committee)., Results: A total of 23,929 individual Culicoides from 20 species was identified, including one species identified in Ireland for the first time, Culicoides cameroni. The most abundant species identified were Culicoides obsoletus/Culicoides scoticus (38%), Culicoides dewulfi (36%), Culicoides pulicaris (9%), Culicoides chiopterus (5%) and Culicoides punctatus (5%), comprising 93% of all Culicoides specimens identified. Collection site habitats were dominated by improved grassland and a combination of broadleaf woodland and native woodland species., Conclusions: The most abundant species of Culicoides identified were the putative vectors of bluetongue virus (BTV) and SBV in northern Europe. Their presence and abundance demonstrates the potential for future transmission of arboviruses among livestock in this region.

Background: In Senegal, the last epidemic of African horse sickness (AHS) occurred in 2007. The western part of the country (the Niayes area) concentrates modern farms with exotic horses of high value and was highly affected during the 2007 outbreak that has started in the area. Several studies were initiated in the Niayes area in order to better characterize Culicoides diversity, ecology and the impact of environmental and climatic data on dynamics of proven and suspected vectors. The aims of this study are to better understand the spatial distribution and diversity of Culicoides in Senegal and to map their abundance throughout the country., Methods: Culicoides data were obtained through a nationwide trapping campaign organized in 2012. Two successive collection nights were carried out in 96 sites in 12 (of 14) regions of Senegal at the end of the rainy season (between September and October) using OVI (Onderstepoort Veterinary Institute) light traps. Three different modeling approaches were compared: the first consists in a spatial interpolation by ordinary kriging of Culicoides abundance data. The two others consist in analyzing the relation between Culicoides abundance and environmental and climatic data to model abundance and investigate the environmental suitability; and were carried out by implementing generalized linear models and random forest models., Results: A total of 1,373,929 specimens of the genus Culicoides belonging to at least 32 different species were collected in 96 sites during the survey. According to the RF (random forest) models which provided better estimates of abundances than Generalized Linear Models (GLM) models, environmental and climatic variables that influence species abundance were identified. Culicoides imicola, C. enderleini and C. miombo were mostly driven by average rainfall and minimum and maximum normalized difference vegetation index. Abundance of C. oxystoma was mostly determined by average rainfall and day temperature. Culicoides bolitinos had a particular trend; the environmental and climatic variables above had a lesser impact on its abundance. RF model prediction maps for the first four species showed high abundance in southern Senegal and in the groundnut basin area, whereas C. bolitinos was present in southern Senegal, but in much lower abundance., Conclusions: Environmental and climatic variables of importance that influence the spatial distribution of species abundance were identified. It is now crucial to evaluate the vector competence of major species and then combine the vector densities with densities of horses to quantify the risk of transmission of AHS virus across the country.

Background: Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) exert a significant impact on animal agriculture worldwide because they transmit bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) to ruminants. Without effective vaccines, BTV/EHDV vector management strategies are needed, particularly in commercial white-tailed deer (WTD) facilities. However, detailed information on the ecology of midge immatures in/around cervid operations is currently lacking. Towards filling this knowledge gap, we conducted two-choice oviposition experiments with field-collected Culicoides stellifer Coquillett (a suspected vector of BTV/EHDV in the USA) under laboratory conditions to examine which natural source from the larval habitat is relatively more attractive for midge oviposition., Methods: Field-collected C. stellifer females (CDC-UV light traps) were given a blood meal from live chicken and examined for their oviposition preferences for individual (or mixed) potential larval habitat oviposition stimuli in two-choice bioassays. Substrates included mud from C. stellifer habitat, mud from allopatric site, vegetation (Sphagnum spp. mosses), field water, WTD manure and de-ionized water (control)., Results: The majority of midges (91%) oviposited in only one dish, with few females (9%) ovipositing in both the dishes. Gravid females demonstrated an overall oviposition preference for substrates with mud and vegetation from the larval habitat, depositing a significantly higher proportion of eggs on mud (52.3%) and vegetation (81.8%) than on controls (≤ 18.2%) (P ≤ 0.0320). Moreover, greater number of eggs per female were deposited on mud (29.5-40.7 depending on trial) and vegetation (38.2) than on controls (≤ 5.8). WTD manure, field water and mud from allopatric site were not found to be more attractive than controls for oviposition. Combining individual substrates (mud + WTD manure; mud + moss + WTD manure + field water) did not elicit greater oviposition responses than mud or moss alone., Conclusions: Management strategies to discourage C. stellifer oviposition in/around commercial cervid facilities should likely focus on mud and/or vegetation, rather than WTD manure. However, further studies are needed to examine whether the spatial distributions of C. stellifer and Sphagnum spp. moss are correlated, and to determine whether targeting vegetation in/around cervid facilities can contribute to reductions in local midge densities.

Background: Microclimatic temperatures provide better estimates of vector-borne disease transmission parameters than standard meteorological temperatures, as the microclimate represent the actual temperatures to which the vectors are exposed. The objectives of this study were to quantify farm-level geographic variations and temporal patterns in the extrinsic incubation period (EIP) of Schmallenberg virus transmitted by Culicoides in Denmark through generation of microclimatic temperatures surrounding all Danish cattle farms., Methods: We calculated the hourly microclimatic temperatures at potential vector-resting sites within a 500 m radius of 22,004 Danish cattle farms for the months April to November from 2000 to 2016. We then modeled the daily EIP of Schmallenberg virus at each farm, assuming vectors choose resting sites either randomly or based on temperatures (warmest or coolest available) every hour. The results of the model output are presented as 17-year averages., Results: The difference between the warmest and coolest microhabitats at the same farm was on average 3.7 °C (5th and 95th percentiles: 1.0 °C to 7.8 °C). The mean EIP of Schmallenberg virus (5th and 95th percentiles) for all cattle farms during spring, summer, and autumn was: 23 (18-33), 14 (12-18) and 51 (48-55) days, respectively, assuming Culicoides select resting sites randomly. These estimated EIP values were considerably shorter than those estimated using standard meteorological temperatures obtained from a numerical weather prediction model for the same periods: 43 (39-52), 21 (17-24) and 57 (55-58) days, respectively. When assuming that vectors actively select the coolest resting sites at a farm, the EIP was 2.3 (range: 1.1 to 4.1) times longer compared to that of the warmest sites at the same farm., Conclusions: We estimated a wide range of EIP in different microclimatic habitats surrounding Danish cattle farms, stressing the importance of identifying the specific resting sites of vectors when modeling vector-borne disease transmission. We found a large variation in the EIP among different farms, suggesting disease transmission may vary substantially between regions, even within a small country. Our findings could be useful for designing risk-based surveillance, and in the control and prevention of emerging and re-emerging vector-borne diseases.

Since 1999, 11 serotypes of bluetongue virus (BTV) similar to Central American or Caribbean strains have been isolated in the southeastern United States, predominantly in Florida. The majority of the incursive serotypes have remained restricted to the southeastern US. In recent years, BTV serotype 3 (BTV-3) has been isolated in areas increasingly distant from Florida. The current study uses whole genome sequencing of recent and historical BTV-3 isolates from the US, Central America and the Caribbean with additional sequences from GenBank to conduct phylogenetic analyses. The individual segments of the BTV genome were analysed to determine if recent BTV-3 isolates are reassortants containing genomic segments from endemic US serotypes or if they retain a majority of Central American/Caribbean genotypes. The analyses indicate that BTV-3 isolates Mississippi 2006, Arkansas 2008 and Mississippi 2009 are closely related reassortants that contain five to six genomic segments that are of US origin and two to three segments of Central American/Caribbean origin. In contrast, the BTV-3 South Dakota 2012 isolate contains seven genomic segments that are more similar to isolates from Central American and the Caribbean. These different evolutionary histories of the BTV-3 isolates suggest that there are at least two different lineages of BTV-3 that are currently circulating in the US.

Bluetongue virus serotype 3 has been detected in a sheep in the Western part of the island of Sicily (Italy). This area is 150 km away from the peninsula of Cap Bon (Tunisia), where recent activities included in the Bluetongue National Surveillance plan demonstrated the widespread circulation of the same BTV strain.

Bluetongue virus (BTV) and Epizootic haemorrhagic disease virus (EHDV) are double-stranded RNA orbiviruses of the Reoviridae family. Bluetongue virus and EHDV infect domestic and wild ruminants and they are transmitted by biting midges of the genus Culicoides (Diptera: Ceratopogonidae). Since 1999, BTV outbreaks have occurred in Tunisia and 4 serotypes, BTV2, BTV1, BTV4 and BTV3, were involved in 2000, 2006, 2009, and 2016, respectively. Epizootic haemorrhagic disease was detected for the rst time in Tunisia and in other Northern African countries in 2006. These incursions have caused considerable economic losses. Our study had the goal to describe diversity, distribution, and seasonal dynamics of Culicoides. Fourteen sampling sites were chosen throughout the country and 2-night trapping of midges was performed monthly from June 2006 to July 2008. A total of 11,582 Culicoides specimens were collected from 336 light traps, comprising 25 species, of which 7 were identi ed for the rst time in Tunisia, increasing to 35 the total number of Culicoides species now reported in this country. Twenty-three pools of parous females belonging to the Culicoides imicola and Culicoides kingi were tested for detection of BTV and EHDV by molecular assays. Both BTV1 and BTV4 were detected in C. imicola.

A convenience sample of sheep and cattle herds around the cities of Harare, Kwekwe and Bulawayo, located in the Highveld region of Zimbabwe, was used to estimate the seroprevalence and sero-incidence of bluetongue virus (BTV) and epizootic haemorrhagic disease virus (EHDV) antibodies. A competitive enzyme-linked immunosorbent assay was used to identify serum antibodies against BTV and EHDV across three rainy seasons. The median sero-prevalence of BTV and EHDV antibodies in cattle was 62% (interquartile range [IQR]: 30-89) and 56% (IQR: 5-77), respectively. In sheep, the median sero-prevalence of BTV and EHDV was 41% (IQR: 19-63) and 0% (IQR: 0-21), respectively. Median sero-incidences of BTV and EHDV antibodies in cattle of 43% (IQR: 22-67) and 27% (IQR: 9-57) respectively were recorded. The median sero-incidence of BTV in sheep was 14% (IQR: 6-23). Based on these preliminary findings, animal health workers in Zimbabwe should continue to monitor the exposure rates of cattle and sheep to BTV and consider the possibility of strains emerging with increased pathogenicity. There are no previous published reports of antibodies against EHDV in Zimbabwe so the possibility of epizootic haemorrhagic disease existing in domestic livestock should now be considered by Zimbabwean animal health officials. Seroconversions to BTV and EHDV occurred predominantly at the end of each rainy season (March and April), which generally corresponds to high numbers of the Culicoides vectors. BTV isolations were made from three individual cows in two of the sentinel herds and all three were identified as serotype 3. This is the first time BTV serotype 3 has been recorded in Zimbabwe, although its presence in neighbouring South Africa is well documented.

Hemorrhagic disease in North America is caused by multiple serotypes of epizootic hemorrhagic disease virus (EHDV) and bluetongue virus (BTV). Diagnostic tests for detection of EHDV and BTV include virus isolation (VI), reverse transcriptase (RT)-PCR, and real-time RT-PCR (rRT-PCR). Our objective was to compare the diagnostic capabilities of three rRT-PCR protocols for detection of EHDV and BTV from naturally infected white-tailed deer (Odocoileus virginianus). We compared the effectiveness of these assays to traditional viral detection methods (e.g., VI) for historic and current clinical cases. Because of the variable nature of tissue collection and storage before diagnostic testing, an evaluation of viral persistence on multiple freeze-thaw events was also conducted. Two of the rRT-PCR assays provided for reliable detection of EHDV and BTV from 100% of clinically affected and VI-confirmed infected animals. Additionally, no significant change in viral titer was observed on multiple freeze-thaw events.

Background: Bluetongue virus (BTV) is transmitted by Culicoides biting midges and causes bluetongue (BT), a clinical disease observed primarily in sheep. BT has a detrimental effect on subsistence farmers in India, where hyperendemic outbreaks impact on smallholdings in the southern states of the country. In this study, we establish a reliable method for testing the toxic effects of deltamethrin on Culicoides and then compare deltamethrin with traditional control methods used by farmers in India., Results: Effects of deltamethrin were initially tested using a colonised strain of Culicoides nubeculosus Meigen and a modified World Health Organisation exposure assay. This method was then applied to field populations of Culicoides spp. in India. The field population of C. oxystoma in India had a greater LC 50 (0.012 ± 0.009%) for deltamethrin than laboratory-reared C.nubeculosus (0.0013 ± 0.0002%). Exposure of C. nubeculosus to deltamethrin at higher ambient temperatures resulted in greater rates of knockdown but a lower mortality rate at 24 h post-exposure. Behavioural assays with C. nubeculosus in WHO tubes provided evidence for contact irritancy and spatial repellence caused by deltamethrin. The field experiments in India, however, provided no evidence for repellent or toxic effects of deltamethrin. Traditional methods such as the application of neem oil and burning of neem leaves also provided no protection., Conclusions: Our study demonstrates that field-collected Culicoides in India are less susceptible to deltamethrin exposure than laboratory-bred C. nubeculosus and traditional methods of insect control do not provide protection to sheep. These low levels of susceptibility to deltamethrin have not been recorded before in field populations of Culicoides and suggest resistance to synthetic pyrethrioids. Alternative insect control methods, in addition to vaccination, may be needed to protect Indian livestock from BTV transmission.

In January 2013, an outbreak of Bluetongue (BT) a ecting a Lacaune sheep ock occurred in Vassouras, Rio de Janeiro state, Brazil. From March to August 2013, blood samples collection and clinical examination were performed monthly, in order to monitor the epidemiological pro le of Bluetongue virus (BTV) circulation and clinical disease in the ock. Agar gel immunodi usion (AGID) and reverse transcription polymerase chain reaction (RT-PCR) targeting BTV segment 10 were used as diagnostic assays. Additionally, insect trapping was conducted in the farm from May to July 2013. The ock serological prevalence to BTV was 80% since the rst month of monitoring, with a variation in the serological rate depending on the sheep age categories. The number of susceptible lambs increased with time, probably due to the decrease of passive immunity. Viral RNA was detected in blood samples, demonstrating viral circulation, prolonged viraemia, and potential source for virus transmission in the region, even in a dry and cool season. The presence of Culicoides pusillus and Culicoides insignis was con rmed in the farm. The emergence of this outbreak in a Brazilian endemic area for BTV emphasises an urgent need of animal surveillance and BTV epidemiological studies.

Tamil Nadu is located in the South-Eastern part of Indian peninsula, between 8.087° and 13.09°N and 76.50° and 80.27°E. Bluetongue (BT) was first reported in this region in sheep during 1982 with regular occurrence thereafter. In 1989-1990, 1997-1998 and 2005-2006, there was wide spread occurrence of BT resulting in huge mortality of sheep. The present study had the goal of isolating the BTV from outbreaks in sheep occurred in Tamil Naadu between 2003-2011 and comparing the VP2 gene sequences of the BTV isolates involved in such outbreaks. Serotypes 1, 2, 16, and 23 of the Bluetongue virus (BTV) have been isolated from sheep during BT outbreaks. BTV-16 has also been isolated in goats and cattle in the region; BTV-2 isolated in Tamil Nadu has homology with BTV-2 isolated in Africa; whereas the BTV-23 isolated in this area has homology with BTV-23 from South East Asia, indicating that both Eastern and Western topotypes of BTV are circulating in ruminant population in Tamil Nadu.

Bluetongue (BT), an arthropod-borne viral disease of ruminants, a ects sheep most severely than other domestic animals. Bluetongue virus serotype 24 (BTV-24) is one of 26 known Bluetongue virus (BTV) serotypes. In this article, we present data of phylogenetic analysis of 9 viral genes (Seg1, Seg2, Seg3, Seg4, Seg5, Seg6, Seg8, Seg9, and Seg10) from 8 Israeli BTV-24 isolates and relate the genotype of the BTV-24 isolates to their phenotype with regard to clinical manifestations. The high level of genetic identity (> 99.6%) between Seg2, Seg4 and Seg5 in all 8 BTV-24 isolates indicated that these segments shared the same viral ancestor. Phylogenetic analysis of Seg1, Seg3, Seg5, Seg8, Seg9, and Seg10 revealed that the Israeli BTV-24 strains comprised 4 variants. Five of the viruses revealed high identity among all 9 segments, and represented variant 1. A second variant (BTV24/3027/6/10), isolated in 2010, showed signi cant variation from variant 1 in 3 gene segments (VP-1, VP-3, and NS-3 genes). A third variant (BTV24/3027/1/10) showed signi cant variation from variant 1 in 6 segments (VP-1, VP-3, VP-6 and NS-1, NS-2 and NS-3 genes), while a fourth variant (BTV24/2214/1/10) showed signi cant variation from variant 1 in 4 segments (VP-1, NS-1, NS-2 and NS-3 genes). These marked di erences in sequence identity indicate that a high level of genetic reassortment is occurring between co-circulating BTV strains in Israel.

High sheep population density, congenial climatic conditions for Culicoides propagation, and susceptible sheep breeds may be contributing to the higher incidence of Bluetongue (BT) in Southern states of India. Sheep farming in this part of the country is nomadic in nature and BT is one of the major infectious diseases inflicting huge losses. Andhra Pradesh is one of the Southern states with high sheep population in India. Although isolation studies in this region were started in 1993, concerted efforts only began in 2002. More than 50 isolates were obtained in the last decade, and 7 Bluetongue virus (BTV) serotypes (1, 2, 9, 10, 12, 16 and 21) were isolated. Among them, BTV-10, BTV-12, and BTV-21 were reported for the first time from India and the genome analysis of these viruses revealed that BTV-10 and BTV-12 have high sequence identity with the modified live virus (MLV) vaccines used in USA and South Africa, respectively. At the same time, BTV-21 has probably originated from Southeast Asia. Furthermore, some of the BTV isolated from Europe have high sequence identity with viruses isolated from Andhra Pradesh indicating common ancestry. The analysis of different isolates involved in outbreaks revealed that more than 1 BTV serotype is involved and that mixed infections with different serotypes is not uncommon. In a limited study conducted during 2005-2009, it was observed that most of the sheep seroconverted to more than 1 serotype, which further supports circulation of multiple serotypes and mixed infections in Andhra Pradesh. Based on the virus isolation data, in this study it was observed that a few serotypes dominate for 3-4 years followed by domination of others. Continuous monitoring of circulating serotypes is essential to understand the distribution and spread BTV in endemic areas and for devising suitable control measures.

Bluetongue (BT) is a non‑contagious arthropod‑borne viral disease of domestic and wild ruminants. It is endemic to India and clinical outbreaks of disease have been reported mainly in sheep, although BT is often asymptomatic in other ruminant species. In the present serological survey, a total of 576 serum samples, comprising of 416 cattle and 160 sheep, covering different agro‑climatic zones of Rajasthan, Uttar Pradesh, and Karnataka states, were screened for the presence of Bluetongue virus (BTV) specific antibodies using competitive enzyme‑linked immunosorbent assay (c‑ELISA). Overall 73.08% (304/416) of the cattle and 53.30% (87/160) of the sheep serum samples were positive for BTV antibodies. The prevalence of BTV antibodies in cattle in different agro‑climatic zones ranged between 60‑80% in Rajasthan and 66‑70% in Uttar Pradesh. During the study, a nested polymerase chain reaction (PCR) based on the BTV NS1 gene (genome segment 5) was optimized for detection of BTV's nucleic acid from a cell adapted strain of BTV‑23, and field derived clinical blood samples. In the present study, 19/70 of cattle and 9/30 of sheep blood samples tested positive for BTV RNA by the nested PCR, which amplified specific products of 274 bp and 101 bp sizes, respectively. From this study, it can be concluded that cattle showed higher percentage of sero‑positivity in comparison to sheep. The improved sero‑surveillance system for BTV in endemic areas will be of great help to understand the epidemiology of BTV and to formulate effective control and preventive strategies.

Bluetongue (BT) is considered endemic in several regions of Brazil. The State of Sao Paulo was divided into 7 cattle production regions (circuits) according the different systems of breeding, operational and logistical capacity of the state veterinary service. At least 1 animal from each property (a total of 1,716 farms) was tested by competitive ELISA for the presence of antibodies against BTV. Sero‑positive sera were subsequently also tested by virus neutralization tests (VNT) using serial dilutions from 1:10 (cutoff) up to 1:640 (in MEM). BTV‑4 neutralizing antibodies were detected in 86% (1,483/1,716) of the animals tested. These results show that BTV‑4 is endemic and widespread in the State of San Paulo and indirectly confirm that in the State there are favourable conditions for the multiplication of competent vectors. However, as no clinical signs have ever been reported in cattle in the region, BTV‑4 infection is likely to occur silently in the State of Sao Paulo.

Bluetongue virus (BTV) was sporadically isolated over a four year period (2010-2014) from several alpaca carcasses that were presented for necropsy at the Western Cape Provincial Veterinary Laboratory, South Africa. Typically, the a ected animals had a history of acute dyspnoea and progressive weakness before death. Consistent hydrothorax and severe lung oedema in all lead to a preliminary diagnosis of Bluetongue, despite the absence of ulceration and hyperaemia of the oral mucosa which is characteristic of this viral infection in sheep. The diagnosis was con rmed by virus isolation in embryonated eggs and subsequent sequencing of the extracted RNA. Assembled sequences were subjected to Blast analysis and two of the isolates could be veri ed as BTV 3. These cases, originating from the Western Cape Province of South Africa, represents the rst o cial report of BTV infection in alpacas in Africa and demonstrates the susceptibility of the species to this disease when maintained in BTV endemic areas.

During the compulsory vaccination programme against bluetongue virus serotype 1 (BTV-1) in Corsica (France) in 2014, a BTV strain belonging to a previously uncharacterized serotype (BTV-27) was isolated from asymptomatic goats. The present study describes the detection and molecular characterization of two additional distinct BTV-27 variants found in goats in Corsica in 2014 and 2015. The full coding genome of these two novel BTV-27 variants show high homology (90-93 % nucleotide/93-95 % amino acid) with the originally described BTV-27 isolate from Corsican goats in 2014. These three variants constitute the novel serotype BTV-27 ('BTV-27/FRA2014/v01 to v03'). Phylogenetic analyses with the 26 other established BTV serotypes revealed the closest relationship to BTV-25 (SWI2008/01) (80 % nucleotide/86 % amino acid) and to BTV-26 (KUW2010/02) (73-74 % nucleotide/80-81 % amino acid). However, highest sequence homologies between individual segments of BTV-27/FRA2014/v01-v03 with BTV-25 and BTV-26 vary. All three variants share the same segment 2 nucleotype with BTV-25. Neutralization assays of anti-BTV27/FRA2014/v01-v03 sera with a reassortant virus containing the outer capsid proteins of BTV-25 (BTV1VP2/VP5 BTV25) further confirmed that BTV-27 represents a distinct BTV serotype. Relationships between the variants and with BTV-25 and BTV-26, hypotheses about their origin, reassortment events and evolution are discussed.

Background: Bluetongue (BT) epidemics have affected the Mediterranean island of Sardinia since 2000. While Culicoides imicola represents the main bluetongue virus (BTV) vector, other European Culicoides biting midges, possibly implicated in virus transmission, have been detected here. Understanding their distribution, seasonal abundance, and infection rates is necessary to predict disease incidence and spread across coastal and inland areas, and to define their role in virus overwintering., Methods: Biting midge abundance was determined by light traps on selected farms representing diverse climatic conditions of Sardinia. Livestock-associated Culicoides species were morphologically and molecularly identified. Infection rates in prevailing midge species captured in 2013 during a BTV-1 outbreak were determined using RT-qPCR based virus detection in insect body pools, supplemented by specific body region analyses. The seasonal infection prevalence in Culicoides samples collected in 2001 in a BTV-2 affected farm was also determined., Results: The Newsteadi complex (C. newsteadi species A and species B) prevailed among all biting midge species (47.7 %), followed by C. imicola (27.8 %) and the Obsoletus complex (C. obsoletus and C. scoticus) (17.6 %). Whilst Culicoides imicola was more abundant along the coast, the Newsteadi complex was frequently collected at higher altitude and the Obsoletus complex was notably associated to cattle farms. Culicoides pulicaris and C. punctatus abundance was found to be marginal in all farms. BTV was detected in parous female samples of all these species, and the full dissemination of the virus within the body of C. imicola, C. obsoletus, C. scoticus, and Newsteadi complex species was confirmed by analyses of thorax and head, containing salivary glands. Higher infection rates were associated with C. scoticus, C. newsteadi species A and species B, compared to C. imicola. The virus was detected in C. newsteadi species A and C. obsoletus in winter and spring, whereas it was mainly found in summer and autumn in C. imicola., Conclusions: In Sardinia, bluetongue virus is transmitted by multiple Culicoides vectors, including C. imicola and the Newsteadi complex being the most important. The Newsteadi complex and other midge species can play an important role in internal areas and are likely to be directly involved in virus overwintering.

This communication reports full genome sequencing of the bluetongue virus-1 (BTV-1) isolate MKD20/08/Ind from goat in northern India. The total BTV-1 genome size was found to be 19,190bp. A comparison study between the Indian isolate and other global isolates revealed that it belongs to the 'Eastern' BTV topotype. The full genome sequence of BTV-1 will provide vital information on its geographical origin and it will also be proved useful for comparing the Indian isolate with global isolates from other host species., (Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.)

Vesicular diseases are of high importance for livestock, primarily because of foot-and-mouth disease (FMD), which is a high-morbidity disease that generates direct losses caused by low milk production, weight loss, and indirect losses because of the need for sanitary barriers. Other vesicular diseases are also of importance for livestock because of direct impacts or because their clinical signs may be confused with those of FMD. We report herein the detection of multiple infections in cattle with suspected vesicular disease in the Brazilian states of Amazonas (AM), Mato Grosso (MT), and Roraima. Thirty-seven epithelial samples from cattle and 1 sample from a buffalo were sent to the laboratory for testing for FMDV and similar disease agents. All samples from MT were positive for parapoxvirus (Pseudocowpox virus and Bovine papular stomatitis virus). In addition, 3 samples were positive for Bluetongue virus, and 5 samples were positive for Bovine herpesvirus 1 Among these samples, 1 was positive for all of these 3 agents. Only 2 samples from AM were negative for parapoxvirus. The molecular tests conducted in this study detected multiple infections, with a high prevalence of parapoxvirus., (© 2016 The Author(s).)

Bluetongue virus (BTV) is an economically important arbovirus of ruminants that is transmitted by Culicoides spp. biting midges. BTV infection of ruminants results in a high viraemia, suggesting that repeated sharing of needles between animals could result in its iatrogenic transmission. Studies defining the risk of iatrogenic transmission of blood-borne pathogens by less invasive routes, such as subcutaneous or intradermal inoculations are rare, even though the sharing of needles is common practice for these inoculation routes in the veterinary sector. Here we demonstrate that BTV can be transmitted by needle sharing during subcutaneous inoculation, despite the absence of visible blood contamination of the needles. The incubation period, measured from sharing of needles, to detection of BTV in the recipient sheep or cattle, was substantially longer than has previously been reported after experimental infection of ruminants by either direct inoculation of virus, or through blood feeding by infected Culicoides. Although such mechanical transmission is most likely rare under field condition, these results are likely to influence future advice given in relation to sharing needles during veterinary vaccination campaigns and will also be of interest for the public health sector considering the risk of pathogen transmission during subcutaneous inoculations with re-used needles.