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Acta Tropica Oct 2022Culicoides biting midges are well known biological vectors of several arboviruses causing more than 100 veterinary and medical diseases worldwide. In Algeria, bluetongue...
Culicoides biting midges are well known biological vectors of several arboviruses causing more than 100 veterinary and medical diseases worldwide. In Algeria, bluetongue virus, which is transmitted by Culicoides midges, is responsible for one of the most critical insect-borne diseases of sheep. For example, this disease caused clinically severe morbidity of about 2,661 confirmed cases out of 21,175 susceptible sheep in Algeria. This study compared the abundance, richness, and diversity of Culicoides species in rural and suburban environments of semi-arid regions in North Africa. It examined the potential influence of the bio-climatic factors on the variation of population sizes and the elevation distribution of biting midges. Specimen collection was carried out from June to September during two successive years (2018 and 2019) using CDC light traps installed at 15 sites in different environments. Culicoides specimens were dissected, slide-mounted, and morphologically identified using the interactive identification key IIKC and various standard morphological criteria. A total of 1,046 Culicoides specimens (1,024 females and 22 males) were trapped and classified into 22 species, belonged to nine distinct subgenera. Two new species records for Algeria and even North Africa are reported: Culicoides albicans (Winnertz, 1852) and Culicoides nubeculosus (Meigen, 1830). Culicoides newsteadi Austen, 1921 (51.6%) was the dominant species, and it was followed by Culicoides punctatus (Meigen, 1804) (16.3%) and Culicoides odiatus Austen, 1921 (11.5%). These three species, comprising 80% of the collected Culicoides, were the most abundant both outside and inside livestock stables in rural and suburban environments. Species diversity was similar in the two settings, with a slight increase in suburban environments. None of the Culicoides species encountered correlated significantly with the climatic factors (mean temperature, precipitation, and relative humidity). Elevation was the most determinant environmental parameter that affected the abundance and distribution of Culicoides midges in the semi-arid and sub-humid areas studied. The maximum distribution of Culicoides species was detected at mid elevations (400‒800 m). Using a modeling approach, we explored for the first time the variation of composition and diversity in Culicoides communities within different climatic regions, environments and livestock settings in Algeria. This survey deepens our understanding of the relationships among environmental factors, abundance, diversity, and geographic distribution of Culicoides. This is a crucial step to assess the epidemiological situation of the diseases transmitted by these biting midges and to allow mitigation of the associated risks.
Topics: Algeria; Animals; Bluetongue virus; Ceratopogonidae; Female; Insect Vectors; Livestock; Male; Sheep
PubMed: 35803337
DOI: 10.1016/j.actatropica.2022.106588 -
Vector Borne and Zoonotic Diseases... Jun 2015Bluetongue (BT) and epizootic hemorrhagic disease (EHD) are noncontagious, insect-transmitted diseases of domestic and wild ruminants caused by related but distinct... (Review)
Review
Bluetongue (BT) and epizootic hemorrhagic disease (EHD) are noncontagious, insect-transmitted diseases of domestic and wild ruminants caused by related but distinct viruses. There are significant gaps in our scientific knowledge and available countermeasures to control an outbreak of orbivirus-induced disease, whether BT or EHD. Both BT virus (BTV) and EHD virus (EHDV) cause hemorrhagic fevers in susceptible ruminants; however, BT is principally a disease of domestic livestock whereas EHD is principally a disease of certain species of wild, non-African ungulates, notably white-tailed deer. The live-attenuated (modified live virus [MLV]) vaccines available in the United States for use in small ruminant livestock do provide good protection against clinical disease following infection with the homologous virus serotype. Although there is increasing justification that the use of MLV vaccines should be avoided if possible, these are the only vaccines currently available in the United States. Specifically, MLVs are used in California to protect sheep against infection with BTV serotypes 10, 11, and 17, and a MLV to BTV serotype 10 is licensed for use in sheep throughout the United States. These MLV vaccines may need to continue to be used in the immediate future for protective immunization of sheep and goats against BT. There are currently no licensed vaccines available for EHD in the United States other than autogenous vaccines. If there is a need to rapidly develop a vaccine to meet an emerging crisis associated with either BTV or EHDV infections, development of an inactivated virus vaccine in a conventional adjuvanted formulation will likely be required. With two doses of vaccine (and in some instances just one dose), inactivated vaccines can provide substantial immunity to the epizootic serotype of either BTV or EHDV. This strategy is similar to that used in the 2006-2008 BTV serotype 8 outbreaks in northern Europe that provided vaccine to the field within 2 years of the initial incursion (by 2008). Further research and development are warranted to provide more efficacious and effective vaccines for control of BTV and EHDV infections.
Topics: Animals; Bluetongue; Bluetongue virus; Hemorrhagic Disease Virus, Epizootic; Livestock; North America; Reoviridae Infections; Ruminants; Sheep; Viral Vaccines
PubMed: 26086559
DOI: 10.1089/vbz.2014.1698 -
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 -
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 -
Transboundary and Emerging Diseases Sep 2022Bluetongue virus (BTV), a member of the genus Orbivirus in the family Reoviridae, is transmitted by biting midges and causes severe disease in domestic and wild...
Bluetongue virus (BTV), a member of the genus Orbivirus in the family Reoviridae, is transmitted by biting midges and causes severe disease in domestic and wild ruminants. In the present study, a BTV strain, BTV-20/GX015/China/2013 (GX015), was isolated from sentinel cattle in Guangxi, China. Virus neutralization tests and phylogenetic analyses based on genomic segments 2 (S2) and 6 (S6) indicated that GX015 belongs to BTV serotype 20 (BTV-20) and represents a new topotype within BTV-20 strains, which makes GX015 the first BTV-20 strain isolated in China. Genomic analyses suggested that the 10 genomic segments of GX015 originated from a reassortment event, in which S2 and S6 are derived from exotic BTV-20 strains (South Africa or Australia), whereas the remaining eight genomic segments are apparently of Chinese origin and most likely share the same ancestor with a Taiwanese BTV-12 strain. Importantly, we evaluated the infectivity and pathogenicity of the BTV-20 strain in mice lacking the interferon receptor (IFNAR mice, a good animal model for studying the pathogenesis, virulence and transmission of BTVs) and sheep for the first time, and found that GX015 causes severe disease and death in IFNAR mice and clinical signs and viraemia in the natural host sheep. These results improve our understanding of the genetic characteristics, diversity and pathogenicity of BTVs, which is important for developing diagnostic methods and vaccines for the surveillance and prevention of bluetongue disease.
Topics: Animals; Bluetongue; Bluetongue virus; Cattle; Cattle Diseases; China; Mice; Phylogeny; Receptors, Interferon; Serogroup; Sheep; Sheep Diseases; Virulence
PubMed: 35403352
DOI: 10.1111/tbed.14555 -
Vector Borne and Zoonotic Diseases... Jun 2024Retrospective serological and case diagnostic data of endemic bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) provide evidence of viral...
Retrospective serological and case diagnostic data of endemic bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) provide evidence of viral transmission among livestock and wildlife from 2016 in Kansas and Nebraska. Serological testing of mature cattle in nine distinct regional zones of Kansas revealed 76% to 100% had detectable antibodies to BTV and/or EHDV. Specimens tested in the Kansas Veterinary Diagnostic Laboratory (55 submissions) were 51% test positive for antibodies to BTV and/or EHDV. Specimens tested in the Nebraska Veterinary Diagnostic Center (283 submissions) were 25% test positive for antibodies to BTV and/or EHDV. Low disease incidence in white-tailed deer and other susceptible wild ungulates was observed during 2016. However, there were no confirmed reports of disease in livestock in either state. The reasons for emergence of significant clinical disease in livestock and wildlife populations remain undefined.
Topics: Animals; Kansas; Nebraska; Reoviridae Infections; Cattle Diseases; Cattle; Hemorrhagic Disease Virus, Epizootic; Bluetongue; Bluetongue virus; Animals, Wild; Deer; Antibodies, Viral; Retrospective Studies; Orbivirus
PubMed: 38386998
DOI: 10.1089/vbz.2022.0096 -
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 -
Ticks and Tick-borne Diseases Mar 2021Wad Medani virus (WMV) belongs to the genus Orbivirus and is a poorly studied arbovirus with unclear medical significance. Presently, a limited number of WMV strains are...
Wad Medani virus (WMV) belongs to the genus Orbivirus and is a poorly studied arbovirus with unclear medical significance. Presently, a limited number of WMV strains are characterized and available in NCBI GenBank, some isolated many years ago. A new WMV strain was isolated in 2012 from Dermacentor nuttalli ticks collected from sheep in the Tuva Republic, Russia, and sequenced using high-throughput methods. Complete coding sequences were obtained revealing signs of multiple intersegment reassortments. These point to a high variability potential in WMV that may lead to the formation of strains with novel properties. These new data on WMV can promote better understanding of: ecological features of its circulation; relationships within the genus Orbivirus; and the medical significance of the virus.
Topics: Animals; Dermacentor; High-Throughput Nucleotide Sequencing; Molecular Conformation; Orbivirus; Phylogeny; Sequence Analysis, RNA; Sheep; Siberia
PubMed: 33291056
DOI: 10.1016/j.ttbdis.2020.101612 -
Emerging Infectious Diseases May 2018A virus isolated from a sick horse from India in 2008 was confirmed by next-generation sequencing analysis to be equine encephalosis virus (EEV). EEV in India is...
A virus isolated from a sick horse from India in 2008 was confirmed by next-generation sequencing analysis to be equine encephalosis virus (EEV). EEV in India is concerning because several species of Culicoides midge, which play a major role in EEV natural maintenance and transmission, are present in this country.
Topics: Animals; Ceratopogonidae; Horse Diseases; Horses; India; Orbivirus; Phylogeny; Reoviridae Infections
PubMed: 29664366
DOI: 10.3201/eid2405.171844