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The Veterinary Quarterly Dec 2020Bluetongue (BT) is an economically important, non-contagious viral disease of domestic and wild ruminants. BT is caused by BT virus (BTV) and it belongs to the genus... (Review)
Review
Bluetongue (BT) is an economically important, non-contagious viral disease of domestic and wild ruminants. BT is caused by BT virus (BTV) and it belongs to the genus and family Reoviridae. BTV is transmitted by midges and causes clinical disease in sheep, white-tailed deer, pronghorn antelope, bighorn sheep, and subclinical manifestation in cattle, goats and camelids. BT is a World Organization for Animal Health (OIE) listed multispecies disease and causes great socio-economic losses. To date, 28 serotypes of BTV have been reported worldwide and 23 serotypes have been reported from India. Transplacental transmission (TPT) and fetal abnormalities in ruminants had been reported with cell culture adopted live-attenuated vaccine strains of BTV. However, emergence of BTV-8 in Europe during 2006, confirmed TPT of wild-type/field strains of BTV. Diagnosis of BT is more important for control of disease and to ensure BTV-free trade of animals and their products. Reverse transcription polymerase chain reaction, agar gel immunodiffusion assay and competitive enzyme-linked immunosorbent assay are found to be sensitive and OIE recommended tests for diagnosis of BTV for international trade. Control measures include mass vaccination (most effective method), serological and entomological surveillance, forming restriction zones and sentinel programs. Major hindrances with control of BT in India are the presence of multiple BTV serotypes, high density of ruminant and vector populations. A pentavalent inactivated, adjuvanted vaccine is administered currently in India to control BT. Recombinant vaccines with DIVA strategies are urgently needed to combat this disease. This review is the first to summarise the seroprevalence of BTV in India for 40 years, economic impact and pathobiology.
Topics: Animals; Bluetongue; Bluetongue virus; India; Ruminants; Seroepidemiologic Studies; Viral Vaccines
PubMed: 33003985
DOI: 10.1080/01652176.2020.1831708 -
Virus Research Oct 2017Eleven viral isolates derived mostly in albopictus C6/36 cells from mosquito pools collected in Southeast Asia and the Americas between 1966 and 2014 contained particles...
Eleven viral isolates derived mostly in albopictus C6/36 cells from mosquito pools collected in Southeast Asia and the Americas between 1966 and 2014 contained particles with electron microscopy morphology typical of reoviruses. Metagenomics analysis yielded the near complete genomes of three novel reoviruses, Big Cypress orbivirus, Ninarumi virus, and High Island virus and a new tetravirus, Sarawak virus. Strains of previously characterized Sathuvarachi, Yunnan, Banna and Parry's Lagoon viruses (Reoviridae), Bontang virus (Mesoniviridae), and Culex theileri flavivirus (Flaviviridae) were also characterized. The availability of these mosquito virus genomes will facilitate their detection by metagenomics or PCR to better determine their geographic range, extent of host tropism, and possible association with arthropod or vertebrate disease.
Topics: Animals; Asia, Southeastern; Culicidae; Flaviviridae; Genome, Viral; Nidovirales; Reoviridae; Sequence Analysis, DNA
PubMed: 28855097
DOI: 10.1016/j.virusres.2017.08.012 -
Equine Veterinary Journal Jan 2021
Topics: African Horse Sickness; African Horse Sickness Virus; Animals; Disease Outbreaks; Horse Diseases; Horses; Thailand; Vaccination; Viral Vaccines
PubMed: 33007121
DOI: 10.1111/evj.13353 -
BMC Veterinary Research Jun 2016Within the last few decades Culicoides spp. (Diptera: Ceratopogonidae) emerged Europe-wide as a major vector for epizootic viral diseases e.g. caused by Bluetongue (BT)...
BACKGROUND
Within the last few decades Culicoides spp. (Diptera: Ceratopogonidae) emerged Europe-wide as a major vector for epizootic viral diseases e.g. caused by Bluetongue (BT) or Schmallenberg virus. In accordance with the EU regulation 1266/2007, veterinary authorities are requested to determine vector-free periods for loosing trade and movement restrictions of susceptible livestock. Additionally, the widely used basic reproduction number [Formula: see text] is optionally applied for risk assessment of vector-borne diseases. Values of R0 < 1 indicate periods with no disease transmission risk. For the determination of vector-free period and R0 a continuously operating daily Culicoides spp. monitoring in Vienna (Austria) was established. It covered the period 2009-2013 and depicts the seasonal vector abundance indoor and outdoor. Future BT and African horse sickness (AHS) outbreak risks were estimated by projecting R0 to climate change scenarios. Therefore, temperature-dependent vector parameters were applied.
RESULTS
The vector-free period lasted about 100 days inside stables, while less than five Culicoides were trapped outdoors on 150 days per season, i.e. winter half year. Additionally, the potential outbreak risk was assessed for BT and AHS. For BT, a basic reproduction number of R0 > 1 was found each year between June and August. The periods without transmission risk, i.e. R0 < 1, were notably higher (200 days). Contrary, values of R0 < 1 were estimated for AHS during the whole period. Finally, the basic reproduction numbers were projected to the future by using temperature forecasts for the period 2014-2100. While the mean summer peak values for BT increase from of R0 = 2.3 to R0 = 3.4 until 2100 (1.1/100 years), no risk for AHS was estimated even under climate warming assumptions.
CONCLUSIONS
Restrictions to trade and movement are always associated with an economic impact during epidemic diseases. To minimize these impacts, risk assessments based on the vector-free period or the basic reproduction number R0 can essentially support veterinary authorities to improve protection and control measurements.
Topics: African Horse Sickness; Animals; Austria; Bluetongue; Bluetongue virus; Ceratopogonidae; Climate; Disease Outbreaks; Entomology; Epidemiological Monitoring; Female; Horses; Insect Vectors; Male; Orbivirus; Orthobunyavirus; Population Dynamics; Risk Assessment; Seasons
PubMed: 27259473
DOI: 10.1186/s12917-016-0710-z -
Veterinaria Italiana Mar 2018Epizootic haemorrhagic disease virus (EHDV) was detected for the first time in Tunisia and in other Northern African countries in 2006. The objective of the present...
Epizootic haemorrhagic disease virus (EHDV) was detected for the first time in Tunisia and in other Northern African countries in 2006. The objective of the present study was to investigate whether EHDV circulated in Tunisian livestock before and after the officially-reported outbreak of 2006. Thus, serum samples from cattle and dromedaries collected in different time periods (before and after 2006) and from different regions of Tunisia were screened for the presence of EHDV antibodies. Serological investigations conducted on cattle and dromedary sera collected in 2000 and 2001 demonstrated no virus circulation on these dates. However, viral circulation was evidenced in 2012 and 2013, although no EHDV cases were officially reported in these years. Serum-neutralization assessed on few ELISA positive samples, confirmed the presence of antibodies against EHDV serotype 6, which was the serotype involved in the EHDV outbreak in the Maghreb region in 2006.
Topics: Animals; Antibodies, Viral; Camelus; Cattle; Hemorrhagic Disease Virus, Epizootic; Tunisia
PubMed: 29631319
DOI: 10.12834/VetIt.973.5129.2 -
Viruses Jul 2021Bluetongue (BT) is a severe and economically important disease of ruminants that is widely distributed around the world, caused by the bluetongue virus (BTV). More than...
Bluetongue (BT) is a severe and economically important disease of ruminants that is widely distributed around the world, caused by the bluetongue virus (BTV). More than 28 different BTV serotypes have been identified in serum neutralisation tests (SNT), which, along with geographic variants (topotypes) within each serotype, reflect differences in BTV outer-capsid protein VP2. VP2 is the primary target for neutralising antibodies, although the basis for cross-reactions and serological variations between and within BTV serotypes is poorly understood. Recombinant BTV VP2 proteins (rVP2) were expressed in , based on sequence data for isolates of thirteen BTV serotypes (primarily from Europe), including three 'novel' serotypes (BTV-25, -26 and -27) and alternative topotypes of four serotypes. Cross-reactions within and between these viruses were explored using rabbit anti-rVP2 sera and post BTV-infection sheep reference-antisera, in I-ELISA (with rVP2 target antigens) and SNT (with reference strains of BTV-1 to -24, -26 and -27). Strong reactions were generally detected with homologous rVP2 proteins or virus strains/serotypes. The sheep antisera were largely serotype-specific in SNT, but more cross-reactive by ELISA. Rabbit antisera were more cross-reactive in SNT, and showed widespread, high titre cross-reactions against homologous and heterologous rVP2 proteins in ELISA. Results were analysed and visualised by antigenic cartography, showing closer relationships in some, but not all cases, between VP2 topotypes within the same serotype, and between serotypes belonging to the same 'VP2 nucleotype'.
Topics: Animals; Antigens, Viral; Bluetongue; Bluetongue virus; Capsid Proteins; Cross Reactions; Enzyme-Linked Immunosorbent Assay; Female; Rabbits; Ruminants; Serogroup; Serotyping; Sheep; Nicotiana
PubMed: 34452321
DOI: 10.3390/v13081455 -
International Journal of Molecular... Apr 2023Bioinformatic analyses have predicted that orbiviruses encode an additional, small non-structural protein (NS5) from a secondary open reading frame on genome segment 10....
Bioinformatic analyses have predicted that orbiviruses encode an additional, small non-structural protein (NS5) from a secondary open reading frame on genome segment 10. However, this protein has not previously been detected in infected mammalian or insect cells. NS5-specific antibodies were generated in mice and were used to identify NS5 synthesised in orbivirus-infected BSR cells or cells transfected with NS5 expression plasmids. Confocal microscopy shows that although NS5 accumulates in the nucleus, particularly in the nucleolus, which becomes disrupted, it also appears in the cell cytoplasm, co-localising with mitochondria. NS5 helps to prevent the degradation of ribosomal RNAs during infection and reduces host-cell protein synthesis However, it helps to extend cell viability by supporting viral protein synthesis and virus replication. Pulldown studies showed that NS5 binds to ssRNAs and supercoiled DNAs and demonstrates interactions with ZBP1, suggesting that it modulates host-cell responses.
Topics: Animals; Mice; Cell Nucleus; DNA; Orbivirus; RNA, Viral; RNA-Binding Proteins; Viral Nonstructural Proteins
PubMed: 37047816
DOI: 10.3390/ijms24076845 -
Veterinaria Italiana Dec 2023Epizootic hemorrhagic disease virus serotype 8 (EHDV-8) emerged in Europe for the first time in late 2022. In this study, we investigated the kinetics of EHDV-8...
Epizootic hemorrhagic disease virus serotype 8 (EHDV-8) emerged in Europe for the first time in late 2022. In this study, we investigated the kinetics of EHDV-8 infection in cattle, sheep, and goats. Following experimental infection with EHDV-8, four out of five calves displayed fever, while another calf exhibited ulcerative and crusty lesions of the muzzle. RNAemia peaked at day 7 post infection in all calves and remained relatively stable till the end of the study, at 78 days post infection. Infectious virus was isolated up to 21 days post infection in one calf. As far as small ruminants are concerned, one sheep experienced fever and two out of five had consistent RNAemia that lasted until the end of the study. Remarkably, infectious virus was evidenced at day 7 post infection in one sheep. In goats, no RNA was observed. All infected animals seroconverted, and a neutralizing immune response was observed in all species, with calves exhibiting a more robust response than sheep and goats. Our study provides insights into the kinetics of EHDV-8 infection and the host immune responses. We also highlight that sheep may also play a role in EHDV-8 epidemiology. Altogether, the data gathered in this study could have important implications for disease control and prevention strategies, providing crucial information to policy makers to mitigate the impact of this viral disease on livestock.
Topics: Sheep; Cattle; Animals; Reoviridae Infections; Goats; Serogroup; Hemorrhagic Disease Virus, Epizootic; Cattle Diseases; Ruminants; Goat Diseases; Sheep Diseases
PubMed: 38117055
DOI: 10.12834/VetIt.3433.23112.1 -
Viruses Jul 2019Bluetongue (BT) is a non-contagious animal disease transmitted by midges of the genus. The etiological agent is the BT virus (BTV) that induces a variety of clinical... (Review)
Review
Bluetongue (BT) is a non-contagious animal disease transmitted by midges of the genus. The etiological agent is the BT virus (BTV) that induces a variety of clinical signs in wild or domestic ruminants. BT is included in the notifiable diseases list of the World Organization for Animal Health (OIE) due to its health impact on domestic ruminants. A total of 27 BTV serotypes have been described and additional serotypes have recently been identified. Since the 2000s, the distribution of BTV has changed in Europe and in the Mediterranean Basin, with continuous BTV incursions involving various BTV serotypes and strains. These BTV strains, depending on their origin, have emerged and spread through various routes in the Mediterranean Basin and/or in Europe. Consequently, control measures have been put in place in France to eradicate the virus or circumscribe its spread. These measures mainly consist of assessing virus movements and the vaccination of domestic ruminants. Many vaccination campaigns were first carried out in Europe using attenuated vaccines and, in a second period, using exclusively inactivated vaccines. This review focuses on the history of the various BTV strain incursions in France since the 2000s, describing strain characteristics, their origins, and the different routes of spread in Europe and/or in the Mediterranean Basin. The control measures implemented to address this disease are also discussed. Finally, we explain the circumstances leading to the change in the BTV status of France from BTV-free in 2000 to an enzootic status since 2018.
Topics: Animals; Bluetongue; Bluetongue virus; Communicable Diseases, Emerging; Europe; France; Mediterranean Region; Public Health Surveillance; Serogroup
PubMed: 31340459
DOI: 10.3390/v11070672 -
Journal of Virology Oct 2018Arboviruses can cause a variety of clinical signs, including febrile illness, arthritis, encephalitis, and hemorrhagic fever. The recent Zika epidemic highlighted the...
Arboviruses can cause a variety of clinical signs, including febrile illness, arthritis, encephalitis, and hemorrhagic fever. The recent Zika epidemic highlighted the possibility that arboviruses may also negatively affect the male reproductive tract. In this study, we focused on bluetongue virus (BTV), the causative agent of bluetongue and one of the major arboviruses of ruminants. We show that rams that recovered from bluetongue displayed signs of testicular degeneration and azoospermia up to 100 days after the initial infection. Importantly, testicular degeneration was induced in rams experimentally infected with either a high (BTV-1)- or a low (BTV-1)-virulence strain of BTV. Rams infected with the low-virulence BTV strain displayed testicular lesions in the absence of other major clinical signs. Testicular lesions in BTV-infected rams were due to viral replication in the endothelial cells of the peritubular areas of the testes, resulting in stimulation of a type I interferon response, reduction of testosterone biosynthesis by Leydig cells and destruction of Sertoli cells and the blood-testis barrier in more severe cases. Hence, BTV induces testicular degeneration and disruption of spermatogenesis by replicating solely in the endothelial cells of the peritubular areas unlike other gonadotropic viruses. This study shows that a naturally occurring arboviral disease can cause testicular degeneration and affect male fertility at least temporarily. During the recent Zika epidemic, it has become apparent that arboviruses could potentially cause reproductive health problems in male patients. Little is known regarding the effects that arboviruses have on the male reproductive tract. Here, we studied bluetongue virus (BTV), an arbovirus of ruminants, and its effects on the testes of rams. We show that BTV was able to induce testicular degeneration in naturally and experimentally infected rams. Testicular degeneration was caused by BTV replication in the endothelial cells of the peritubular area surrounding the seminiferous tubules (the functional unit of the testes) and was associated with a localized type I interferon response, destruction of the cells supporting the developing germinal cells (Sertoli cells), and reduction of testosterone synthesis. As a result of BTV infection, rams became azoospermic. This study highlights that problems in the male reproductive tract caused by arboviruses could be more common than previously thought.
Topics: Animals; Bluetongue; Bluetongue virus; Endothelium, Vascular; Infertility, Male; Male; Sheep; Sheep Diseases; Spermatogenesis; Testis; Testosterone; Virulence; Virus Replication
PubMed: 30021901
DOI: 10.1128/JVI.01131-18