Search

Akabane virus is a teratogenic pathogen transmitted by Culicoides spp. to ruminants. The virus induces anomalies in the central nervous system in the developing fetus, resulting in arthrogryposis-hydranencephaly (A-H) syndrome. During three outbreaks of the disease (2002, 2013, and 2020), 77 calves were born in Varamin, Iran, with A-H syndrome. The presenting neurologic signs were categorized into three main groups, as common, less common, and uncommon signs. The common signs were unawareness of the surroundings, blindness, deep depression, partial failure of suckling, and unintelligent behavior. The less commonly noted signs were hyperexcitability, regurgitation, head pressing, compulsive walking, and kicking, while the uncommon signs comprised protrusion of the tongue, making sounds resembling barking, carnivore-like milk drinking, and deafness. Arthrogryposis, dome-shaped skull, kyphosis, torticollis, lordosis, scoliosis, and spina bifida were the diagnosed skeletal defects. Upon necropsy, hydranencephaly, hydrocephaly, and microencephaly were seen in the calves presenting neurologic signs, while astrocytosis, astrogliosis, focal gliosis, perivascular, perineuronal, and submeningeal edema, perivascular cuffing, non-suppurative meningitis, non-suppurative encephalitis and lymphoplasmacytic infiltration, and perivascular and parenchymal hemorrhage were seen in samples obtained from the brains. RT-PCR detected Akabane virus in the brain tissues of the affected calves. This is the first clinical study of Akabane disease in calves in Iran. [ABSTRACT FROM AUTHOR]

In November 2021, an investigation was conducted into an outbreak of abortion, stillbirth, and the birth of calves with congenital abnormalities (arthrogryposis and hydranencephaly) at a dairy farm in Dasht-e-Mughan city, Ardabil province. A total of 70 cows experienced these issues. To determine the cause of the outbreak, post-mortem brain tissue samples were collected from two calves affected by hydranencephaly, which occurred shortly after their birth. Polymerase chain reaction (PCR) testing was conducted for multiple viruses, including bovine viral diarrhea (BVD), border disease, Akabane, Schmallenberg, and bluetongue viruses (BTVs). The samples were positive only for Akabane virus. Serum samples were collected from a group of 60 cattle, consisting of 45 adult cows and 15 younger calves aged between 8 to 10 months. These samples were analyzed to detect the presence of antibodies against the Akabane and Schmallenberg viruses. Both of these viruses are known to be responsible for causing abortion, stillbirth, and congenital abnormalities in calves. Among 45 cows that tested by competitive enzyme-linked immunosorbent assay (cELISA), 26.66% and 33.33% exhibited antibodies against Akabane and Schmallenberg viruses, respectively. Notably, 20.00% of cows co-exhibited antibodies for both viruses. Despite PCR evidence implicating Akabane virus as the principal etiology of clinical signs observed in the affected herd, the high coseropositivity to Schmallenberg virus, warrants a thorough investigation into potential viral interactions. Further research is required to determine the source of the virus and their transmission routes. This information could facilitate the refinement of disease control strategies and improving the management of reproductive challenges in such affected herds. [ABSTRACT FROM AUTHOR]

IntroductionAkabane virus (AKAV) is a worldwide epidemic arbovirus belonging to the Bunyavirales order that predominantly infects livestock and causes severe congenital malformations. Reporter-expressing recombinant virus represents a powerful tool to characterize the viral biology in vitro and in vivo.MethodsIn this study, we have successfully established a reverse genetics system for AKAV. The recued virus possessed similar growth characteristics to the parental virus in vitro. Moreover, the recombinant AKAV reporter viruses expressing nanoluciferase (Nluc) or mWasabi were constructed by inserting into S segment, named rAKAV-Nluc and rAKAV-mWasabi, respectively.ResultsWe investigated the virological characteristics of rAKAV-Nluc and rAKAV-mWasabi and found that rAKAV-Nluc displayed similar growth kinetics as the parental virus and could stably produce the nano-luciferase even after 10 rounds of serial passages. rAKAV-mWasabi also exhibited comparable growth kinetics and genetic stability as the parental virus. We further used the two reporter viruses to test the susceptibility of different cell lines to AKAV and found that cell lines derived from various host species, including human, swine, cattle, and monkey enables AKAV replication efficiently, accelerating our understanding of the AKAV cell tropism range.DiscussionTaken together, our established reverse genetics system for AKAV provides more convenient screening tools and can be used to study AKAV virulence and tropism, and to elucidate the molecular biology of AKAV.

Akabane virus (AKAV) is known as a major teratogenic agent of ruminant fetuses. In this study, we investigated the relationship between porcine abnormal deliveries and AKAV by serology, pathology, and virology investigations using specimens from 16 stillborn fetuses delivered in southern Japan between 2013 and 2015. The major clinical manifestations in stillborn fetuses were hydranencephaly, arthrogryposis, spinal curvature, and both skeletal muscle and subcutaneous edema. Histologic examination of the specimens identified atrophy of skeletal muscle fibers accompanied by adipose replacement. Nonsuppurative encephalomyelitis and decreased neuronal density in the ventral horn of the spinal cord were shown in two separate fetuses, respectively. Neutralizing antibody titers to AKAV were detected in most of the tested fetuses (13/16). The AKAV sequences detected in the affected fetuses in 2013 and 2015 were highly identical and closely related to Japanese AKAV isolates which were isolated in 2013 and sorted into genogroup I of AKAV. Immunohistochemistry visualized AKAV antigens in the neuronal cells of the central nervous system of the fetuses. These findings indicate that AKAV was involved in the birth of abnormal piglets at the affected farm. The clinical manifestations and histopathological features in the stillborn fetuses were very similar to those in ruminant neonates affected by AKAV. To avoid misdiagnosis and to evaluate the precise impact of AKAV on pig reproduction, AKAV should be considered in differential diagnoses of reproductive failures in pigs. [ABSTRACT FROM AUTHOR]

Abstract Background Akabane virus (AKAV) is a teratogenic and neuropathogenic arbovirus that infects livestock and wild animals. AKAVs are endemic arboviruses from dairy farms in Taiwan in 1989, and the first sequence was detected in cattle with nonsuppurative encephalitis in 1992. Objectives This study aims to understand the epidemiological relationships of the akabane viruses between Taiwan and nearby places. Methods In this study, 17 specimens were identified or isolated from vector insects, and ruminant fetuses collected from 1992 to 2015 were sequenced and analysed. Results Sequence analyses revealed all Taiwanese AKAVs belonged to genogroup Ia but diverged into two clusters in the phylogenetic trees, implying that at least two invasive events of AKAV may have occurred in Taiwan. Conclusions The two clusters of AKAVs could still be identified in Taiwan in 2015, and a reassortment event was observed, indicating that the two clusters of AKAVs are already endemic in Taiwan.

Aim: The aim of the study was to investigate the role of Bovine herpesvirus- 1 (BHV-1), Schmallenberg virus (SBV), , Akabane virus (AKAV) and pestivirus in cattle abortion cases in the Aegean Region of Turkey between 2015 and 2019. Materials and Methods: In this study, 204 bovine abortions that occurred in the Aegean region of Turkey between the years 2015 and 2019 were investigated. While BHV-1, SBV, and pestivirus were examined with real-time PCR, AKAV was examined with nested-PCR. Results: In our study, 25 (12.3%) of the samples analyzed were positive for pestiviruses, 1 (0.5%) was positive for Akabane, and 1 (0.5%) was positive for BHV-1. SBV was not detected. According to these results, the viral agent causing most abortions in the Aegean region was found to be pestivirus. The most abortion-related material was sent to the lab in 2018, followed by 2019, 2017, 2016, and 2015. Conclusion: Based on the results of this study, future evaluations should consider the cattle abortion agents detected in the Aegean region, and control and monitoring studies should be established.

Akabane virus (AKAV) has been detected in a variety of host species in China, but there are only limited records of its occurrence in goats. However, more attention needs to be paid to understanding the diversity of viruses in this species. The aim of the study was to explore the genotype characteristics and variation trend of AKAV and their relationship with virulence in Yunnan, China.

Background: Akabane virus (AKAV) is a teratogenic and neuropathogenic arbovirus that infects livestock and wild animals. AKAVs are endemic arboviruses from dairy farms in Taiwan in 1989, and the first sequence was detected in cattle with nonsuppurative encephalitis in 1992. Objectives: This study aims to understand the epidemiological relationships of the akabane viruses between Taiwan and nearby places. Methods: In this study, 17 specimens were identified or isolated from vector insects, and ruminant fetuses collected from 1992 to 2015 were sequenced and analysed. Results: Sequence analyses revealed all Taiwanese AKAVs belonged to genogroup Ia but diverged into two clusters in the phylogenetic trees, implying that at least two invasive events of AKAV may have occurred in Taiwan. Conclusions: The two clusters of AKAVs could still be identified in Taiwan in 2015, and a reassortment event was observed, indicating that the two clusters of AKAVs are already endemic in Taiwan. [ABSTRACT FROM AUTHOR]

Abstract Background Akabane virus (AKAV) is an important insect-borne virus which is widely distributed throughout the world except the Europe and is considered as a great threat to herbivore health. Results An AKAV strain defined as TJ2016 was firstly isolated from the bovine sera in China in 2016. Sequence analysis of the S and M segments suggested that the isolated AKAV strain was closely related to the AKAV strains JaGAr39 and JaLAB39, which belonged to AKAV genogroup II. To further study the pathogenic mechanism of AKAV, the full-length cDNA clone of TJ2016 S, M, and L segment was constructed separately into the TVT7R plasmid at the downsteam of T7 promoter and named as TVT7R-S, TVT7R-M, and TVT7R-L, respectively. The above three plasmids were further transfected into the BSR-T7/5 cells simultaneously with a ratio of 1:1:1 to produce the rescued virus AKAV. Compared with the parental wild type AKAV (wtAKAV), the rescued virus (rAKAV) was proved to be with similar cytopathic effects (CPE), plaque sizes and growth kinetics in BHK-21 cells. Conclusion We successfully isolated a AKAV strain TJ2016 from the sera of cattle and established a reverse genetic platform for AKAV genome manipulation. The established reverse genetic system is also a powerful tool for further research on AKAV pathogenesis and even vaccine studies.

Copyright of Eurasian Journal of Veterinary Sciences is the property of Eurasian Journal of Veterinary Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Akabane virus (AKAV) is characterized by abortion, stillbirth, premature birth, and congenital deformities in livestock and is widely distributed throughout Australia, Southeast Asia, East Asia, the Middle East, and Africa. Gc protein is the major neutralizing target of AKAV and is often considered as an immunogen to prepare neutralizing antibodies. In this study, we prepared and characterized three monoclonal antibodies (mAbs), 4D1, 4E6, and 4F12, against the Gc protein of AKAV (TJ2016 strain). Western blot (WB) and indirect immunofluorescence assay (IFA) analysis proved that the mAbs can react with both the truncated recombinant AKAV Gc protein and the natural Gc protein produced in the AKAV-infected cells. Further research demonstrated that these mAbs possess neutralizing activity. We next defined a neutralizing epitope 1134SVQSFDGKL1142 by screening a panel of overlapping peptides spanning the truncated Gc protein (aa991∼1232) using the generated neutralizing mAbs. Bioinformatic analysis shows that the neutralizing epitope is highly conserved across different genotypes of AKAV. The newly produced neutralizing mAbs and the identified neutralizing epitope in this study enrich the antigenic epitope information of the AKAV Gc protein and could have potential applications in the development of antigen and antibody detection systems that are specific to AKAV. • Three mAbs against Gc protein of AKAV were prepared and characterized. • These mAbs possess neutralizing activity. • A neutralizing epitope 1134SVQSFDGKL1142 was identified by using these mAbs. • The epitope was highly conserved among the major genotypes (Ⅰ, Ⅱ, Ⅲ and Ⅴ) of AKAV. [ABSTRACT FROM AUTHOR]

Akabane virus (AKAV), belonging to the genus Orthobunyavirus and family Peribunyaviridae, causes reproductive and congenital abnormalities in ruminants. Its envelope glycoprotein Gc is a neutralizing antigen, on which at least five distinct antigenic regions have been identified. We attempted to identify the domains using truncated recombinant AKAV Gc proteins expressed in Escherichia coli and monoclonal antibodies (mAbs) with AKAV-neutralizing activity. Dot blot analysis revealed that amino acid positions 1–97 and 189–397 (Gc1–97 and Gc189–397) in the truncated recombinant proteins reacted with the mAbs. Additionally, AKAV was neutralized by sera from mice immunized with these recombinant proteins. The results suggested that the two domains contain neutralizing epitopes and could be potential subunit vaccines against AKAV. [ABSTRACT FROM AUTHOR]

Objective. This study was aimed to investigate the presence of pestivirus, schmallenberg virus (SBV), akabane virus (AKAV), and determined the seasonal distribution in small ruminant abortion cases. Materials and methods. A total of 164 small ruminant aborted fetuses (39 goats and 125 sheep) were investigated in the West Turkey between the years of 2015 and 2019. While the SBV and pestivirus were examined with real-time RT-PCR, the AKAV was examined with nested-PCR. Results. In this study, while four sheep (2.3%) were found to be pestivirus positive, nine sheep and one goat (5.9%) were found to be AKAV positive. SBV was detected in none of the animals. According to the results of the studies carried out, AKAV, a vector-borne virus, was detected more than other viruses in sheep and goat abortions in West Turkey. A positive sample of akabane virus detected in sheep fetuses was sequenced based on the partial S segment. This sample showed 99-100% similarity to the Adana-15, Aksu-1, and Aksu-2 isolates previously detected in Southern Turkey. Phylogenetic analysis showed that the sequenced isolate in this study was clustered within genogroup Ib. Another important piece of data revealed in this study was the determination of the seasonal distribution of sheep and goat abortions. Abortion cases which started to increase in November reached a peak in February and declined till August. Conclusions. This is the first study in the Aegean Region (including seven provinces) in which three important viral agents were simultaneously investigated in small ruminant aborted fetuses. [ABSTRACT FROM AUTHOR]

Objective. This study was aimed to investigate the presence of pestivirus, schmallenberg virus (SBV), akabane virus (AKAV), and determined the seasonal distribution in small ruminant abortion cases Materials and Methods. A total of 164 small ruminant aborted fetuses (39 goats and 125 sheep) were investigated in West Turkey between the years of 2015 and 2019. While the SBV and pestivirus were examined with real-time RT-PCR, the AKAV was examined with nested-PCR. Results. In this study, while four sheep (2.3%) were found to be pestivirus positive, nine sheep and one goat (5.9%) were found to be AKAV positive. SBV was detected in none of the animals. According to the results of the studies carried out, AKAV, a vector-borne virus, was detected more than other viruses in sheep and goat abortions in West Turkey. A positive akabane virus sample detected in sheep fetuses was sequenced based on the partial S segment. This sample showed 99-100% similarity to the Adana-15, Aksu-1, and Aksu-2 isolates previously detected in Southern Turkey. Phylogenetic analysis showed that the sequenced isolate in this study was clustered within genogroup Ib. Another important piece of data revealed in this study was the determination of the seasonal distribution of sheep and goat abortions. Abortion cases which started to increase in November reached a peak in February and declined till August. Conclusions. This is the first study in the Aegean Region (including seven provinces) in which three important viral agents were simultaneously investigated in small ruminant aborted fetuses.

Background: Akabane virus (AKAV) is an important insect-borne virus which is widely distributed throughout the world except the Europe and is considered as a great threat to herbivore health. Results: An AKAV strain defined as TJ2016 was firstly isolated from the bovine sera in China in 2016. Sequence analysis of the S and M segments suggested that the isolated AKAV strain was closely related to the AKAV strains JaGAr39 and JaLAB39, which belonged to AKAV genogroup II. To further study the pathogenic mechanism of AKAV, the full-length cDNA clone of TJ2016 S, M, and L segment was constructed separately into the TVT7R plasmid at the downsteam of T7 promoter and named as TVT7R-S, TVT7R-M, and TVT7R-L, respectively. The above three plasmids were further transfected into the BSR-T7/5 cells simultaneously with a ratio of 1:1:1 to produce the rescued virus AKAV. Compared with the parental wild type AKAV (wtAKAV), the rescued virus (rAKAV) was proved to be with similar cytopathic effects (CPE), plaque sizes and growth kinetics in BHK-21 cells. Conclusion: We successfully isolated a AKAV strain TJ2016 from the sera of cattle and established a reverse genetic platform for AKAV genome manipulation. The established reverse genetic system is also a powerful tool for further research on AKAV pathogenesis and even vaccine studies. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Simbu serogroup of orthobunyaviruses includes several pathogens of veterinary importance, among them Schmallenberg virus (SBV), Akabane virus (AKAV) and Shuni virus (SHUV). They infect predominantly ruminants and induce severe congenital malformation. In adult animals, the intra vitam diagnostics by direct virus detection is limited to only a few days due to a short-lived viremia. For surveillance purposes the testing for specific antibodies is a superior approach. However, the serological differentiation is hampered by a considerable extent of crossreactivity, as viruses were assigned into this serogroup based on antigenic relatedness. Here, we established a glycoprotein Gc-based triplex enzyme-linked immunosorbent assay (ELISA) for the detection and differentiation of antibodies against SBV, AKAV, and SHUV. A total of 477 negative samples of various ruminant species, 238 samples positive for SBV-antibodies, 36 positive for AKAVantibodies and 53 SHUV antibody-positive samples were tested in comparison to neutralization tests. For the newly developed ELISA, overall diagnostic specificities of 84.56%, 94.68% and 89.39% and sensitivities of 89.08%, 69.44% and 84.91% were calculated for SBV, AKAV and SHUV, respectively, with only slight effects of serological cross-reactivity on the diagnostic specificity. Thus, this test system could be used for serological screening in suspected populations or as additional tool during outbreak investigations. [ABSTRACT FROM AUTHOR]

In this study, blood samples collected from dromedary camels in the Algerian provinces of Laghouat and Ghardaia, which were kept in the same pastures and in the same herds with sheep and goats, were examined to detect antibodies to the Bluetongue (BT) and Akabane (AKA) viruses using enzyme linked immunosorbent assay and serum neutralization tests, respectively. Overall, 16 (14.4%) and 2 (1.8%) of 111 tested camel serum samples were seropositive for the BT virus (BTV) and the AKA virus (AKAV), respectively. The present study determined that BTV infection was prevalent in camels in Algeria, and antibodies to the AKAV were also detected for the first time in Algerian camels. [ABSTRACT FROM AUTHOR]

Aim: The study was conducted in Basrah, Iraq, to diagnose congenital arthrogryposis-hydranencephaly syndrome caused by Akabane virus (AKAV) in calves. Materials and Methods: Affected animals (42 calves) are about 2-27 days old from both sexes show signs of arthrogryposis and hydranencephaly. Eight clinically healthy newborn calves were considered as controls. Diagnosis of AKAV was confirmed using a competition enzyme-linked immunosorbent assay test. Results: Results show that all affected calves were found seropositive. Furthermore, a significant increase in total leukocyte count in diseased calves due to a significant increase in the absolute lymphocyte number indicated in affected calves than in controls. Moreover, a significant increase in sedimentation rate of erythrocytes was also encountered in diseased calves than in controls. In addition, a significant increase in haptoglobin level and fibrinogen was also detected. Conclusion: Diagnosis of AKAV infection of Basrah Governorate, Iraq, will provide useful epidemiological information for cattle and other domesticated animals. Therefore, abortion could be prevented and controlled.

Akabane virus, a member of the Orthobunyavirus genus in the family Bunyaviridae, causes congenital abnormalities and arthrogryposis with hydrocephalus or hydroencephaly in ruminants. Tis study intends to describe the clinical signs, gross and histopathological features seen in 25 afected lambs in an outbreak of congenital arthrogryposis with hydrocephalus or hydranencephaly in Al-Muthanna governorate, Iraq afer a large number of stillbirths and musculoskeletal deformities from October 2017 to May 2018. Skeletal muscle hypoplasia was seen in the limbs of the afected lambs accompanied with severe arthrogryposis and gross visible brain malformations. In addition, fetal mummifcations, stillbirths, and dead lambs were also seen. Te most histopathological features in muscle fbers were degenerative lesions and absences of cross-striation accompanied with mild infltration of neutrophils and mononuclear cells in severely afected lambs. Te meninges of afected lambs revealed fused membranes with focal areas of fbrous thickenings and necrotic debris. In conclusion, according to clinical signs, gross and histopathological investigations, Akabane virus, a member of the Orthobunyavirus genus in the family Bunyaviridae, causes congenital abnormalities and arthrogryposis with hydrocephalus or hydroencephaly in ruminants and could be the cause of this outbreak, although future studies must be performed to confrm the etiology of this outbreak. Moreover, other causes of hydrocephalus or cerebellar malformation, such as Schmallenberg virus, bluetongue virus and border disease virus and teratogenic plants that lead to arthrogryposis, have to be investigated. Also, the authorities should take prevention and control measurements to stop the replication of arthropod vectors.

Akabane virus (AKAV) is an arbovirus belonging to the family Bunyaviridae, genus Orthobunyavirus. AKAV consists of three-segment (L, M, and S RNA segments), negative single-stranded RNA. The aim of this study was to investigate an in situ hybridization method (ISH) in a Vero E6 cell line infected with Akabane virus. The 320 base pair amplicon was obtained by RT-PCR with a primer pair and labeled with digoxigenin. Akabane virus RNAs were seen as a granular pattern in the cytoplasm of infected cells. As a result, the expression of the particular Akabane virus gene area was successfully disclosed in the current investigation using the ISH method with a digoxigenin-labeled probe., Competing Interests: The authors declared no conflicts of interest in relation to the research, authorship or publication of this article., (© 2024 The Journal of Biological Methods, All rights reserved.)

Viral infectious diseases are important causes of reproductive disorders, as abortion, fetal mummification, embryonic mortality, stillbirth, and congenital abnormalities in animals and in humans. In this chapter, we provide an overview of some virus, as important agents in teratology.We begin by describing the Zika virus, whose infection in humans had a very significant impact in recent years and has been associated with major health problems worldwide. This virus is a teratogenic agent in humans and has been classified as a public health emergency of international concern (PHEIC).Then, some viruses associated with reproductive abnormalities on animals, which have a significant economic impact on livestock, are described, as bovine herpesvirus, bovine viral diarrhea virus, Schmallenberg virus, Akabane virus, and Aino virus.For all viruses mentioned in this chapter, the teratogenic effects and the congenital malformations associated with fetus and newborn are described, according to the most recent scientific publications., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

A surveillance of Culicoides biting midges with light suction traps was conducted in the northern region of Honshu, main island of Japan, during the summers and autumns of 2009 and 2010. A total of 106 trap collections across 37 cattle farms were investigated for the structure and distribution of Culicoides species. Forty-thousand and one hundred forty-nine specimens of Culicoides biting midges were identified at the species level, and ≥19 species were included in the specimens. Culicoides oxystoma, which is a known major vector of Akabane virus (AKAV), appeared not to have expanded in northern Honshu during the surveillance. Of the potential AKAV vectors suggested by a previous laboratory experiment, C. tainanus and C. punctatus widely infested cowsheds across northern Honshu. The AKAV circulation was confirmed by serological surveillance of sentinel cattle in northern Honshu during the summer and autumn of 2010 and, consequently, >200 calves affected by the virus were identified as of spring 2011. Our surveillance demonstrated that C. tainanus and C. punctatus were widely spread and often dominated at cattle farms in/around the seroconverted regions, and our results thus suggest that these species played a critical role in the AKAV transmission in 2010. Because the distribution ranges of C. tainanus and C. punctatus cover almost all of mainland Japan, a potential risk of AKAV transmission might be expected even in areas outside the range of C. oxystoma. [ABSTRACT FROM AUTHOR]

Akabane virus (AKAV) is an important insect-borne virus belonging to the genus Orthobunyavirus, the Peribunyaviridae family. An AKAV defined as GXDH 01 here, was isolated for the first time from blood from a sentinel goat in China in 2016, and its full-length open reading frames (ORFs) were sequenced in this study. Sequence analysis suggested that the isolate GXDH 01 probably had undergone a reassortment incident and acquired L segments from other strain originating from an attenuated vaccine, such as OBE-1. This study aims to provide more understanding as to the origin and epidemiology of AKAV in China. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the abundance of mosquitoes and circulation of mosquito-borne arboviruses from 16 villages in 8 cities of Hunan Province, China, in July–August of 2010 and in August of 2011. In total, 16,076 mosquitoes consisting of seven species from four genera were collected by ultraviolet-light trap. Culex quinquefasciatus was the most common species, accounting for 50.63% (8140/16,076) of the total. Anopheles sinensis (24.26%, 3900/16,076) made up the second most common species, followed by Culex tritaeniorhynchus (9.76%, 1569/16,076). The proportions of Culex pipiens pallens, Armigeres subalbatus, and Culex modestus were 6.7%, 5.2%, and 3.31%, respectively. Fourteen Aedes albopictus were detected. The mosquitoes were identified by morphologic characteristics and frozen in liquid nitrogen. The mosquitoes were pooled, triturated, and centrifuged. The clarified supernatant was used to inoculate monolayers of C6/36 and baby hamster kidney-21 cells. We obtained six virus isolates that caused cytopathic effects. Phylogenetic analysis revealed that two isolates were Akabane virus (AKAV, from A. sinensis and C. quinquefasciatus), two isolates were Japanese encephalitis virus (from C. pipiens pallens and C. quinquefasciatus), and two isolates were Tibet orbivirus (from C. quinquefasciatus and C. tritaeniorhynchus). This is the first report of AKAV isolated from A. sinensis and C. quinquefasciatus in nature in China. The detection of AKAV in these species confirms circulation of AKAV in Hunan province and suggests potential challenges to the prevention and control of arthropod-borne animal viruses in mainland China. [ABSTRACT FROM AUTHOR]

The Simbu serogroup of orthobunyaviruses includes several pathogens of veterinary importance, among them Schmallenberg virus (SBV), Akabane virus (AKAV) and Shuni virus (SHUV). They infect predominantly ruminants and induce severe congenital malformation. In adult animals, the intra vitam diagnostics by direct virus detection is limited to only a few days due to a short-lived viremia. For surveillance purposes the testing for specific antibodies is a superior approach. However, the serological differentiation is hampered by a considerable extent of cross-reactivity, as viruses were assigned into this serogroup based on antigenic relatedness. Here, we established a glycoprotein Gc-based triplex enzyme-linked immunosorbent assay (ELISA) for the detection and differentiation of antibodies against SBV, AKAV, and SHUV. A total of 477 negative samples of various ruminant species, 238 samples positive for SBV-antibodies, 36 positive for AKAV-antibodies and 53 SHUV antibody-positive samples were tested in comparison to neutralization tests. For the newly developed ELISA, overall diagnostic specificities of 84.56%, 94.68% and 89.39% and sensitivities of 89.08%, 69.44% and 84.91% were calculated for SBV, AKAV and SHUV, respectively, with only slight effects of serological cross-reactivity on the diagnostic specificity. Thus, this test system could be used for serological screening in suspected populations or as additional tool during outbreak investigations.

Highlights • A probe-based real-time RT-PCR for the complete Simbu serogroup was established. • Species identification of detected viruses by subsequent sequence analysis is enabled. • A comprehensive panel of Simbu viruses could be reliably detected. • Co-circulation of AKAV and SHUV in Israel was confirmed using the new system. Abstract Simbu serogroup viruses induce acute clinical diseases and abnormal courses of pregnancies in livestock. In Israel, two members of this serogroup, namely Akabane virus (AKAV) and Shuni virus (SHUV), were recently detected and, in Europe, Schmallenberg virus (SBV) poses a threat to ruminants. To address this emerging problem, a universal S-segment-based real-time RT-PCR assay (Uni-S) for the detection of Simbu serogroup viruses was established, which, additionally, enabled species identification of the detected viruses by subsequent sequencing. The newly developed probe-based PCR system enabled reliable detection of a comprehensive panel of Simbu viruses. Furthermore, several SBV isolates and German field samples were tested by the new Uni-S system in comparison to a SBV-specific real-time RT-PCR and both assays exhibited equally high levels of sensitivities. Finally, co-circulation of AKAV and SHUV in Israel was confirmed by analyzing field samples using the Uni-S assay followed by sequence analysis of the positive samples. To validate the test specificity, blood and tissue samples from animals negative for Simbu viruses, preparations of genetically related viruses and additional ruminant pathogens were examined and all were found to be negative. In conclusion, the new assay enabled sensitive and rapid universal molecular detection of Simbu viruses and is expected to serve as a valuable method for infection diagnosis, especially in regions where several Simbu serogroup members circulate. [ABSTRACT FROM AUTHOR]

Arthropod-borne viruses (Arboviruses) are transmitted by arthropods such as Culicoides biting midges and cause abortion, stillbirth, and congenital malformation in ruminants, apparently leading to economic losses to farmers. To monitor the distribution of Culicoides and to determine their relationship with different environmental conditions (temperature, humidity, wind speed, and altitude of the farms) on 5 cattle farms, Culicoides were collected during summer season (May-September) in 2016 and 2017, and analyzed for identification of species and detection of arboviruses. About 35% of the Culicoides were collected in July and the collection rate increased with increase in temperature and humidity. The higher altitude where the farms were located, the more Culicoides were collected on inside than outside. In antigen test of Culicoides against 5 arboviruses, only Chuzan virus (CHUV) (2.63%) was detected in 2016. The Akabane virus (AKAV), CHUV, Ibaraki virus and Bovine ephemeral fever virus (BEFV) had a positive rate of less than 1.8% in 2017. In antigen test of bovine whole blood, AKAV (12.96%) and BEFV (0.96%) were positive in only one of the farms. As a result of serum neutralization test, antibodies against AKAV were generally measured in all the farms. These results suggest that vaccination before the season in which the Culicoides are active is probably best to prevent arbovirus infections. [ABSTRACT FROM AUTHOR]

Summary: Akabane virus (AKAV) is teratogenic to the foetus of domestic ruminants and causes a significant reproduction loss in cattle in Japan. In several past epizootics in cattle, AKAV was also associated with post‐natal encephalomyelitis, mainly in calves and young stock. Previously analysed AKAV isolates in East Asia form two major clusters, genogroups I and II, with isolates involved in encephalomyelitis belonging mainly to the former. Between 2007 and 2013, AKAV epizootics were regularly observed in Japan during the summer/autumn season, and abnormal deliveries and post‐natal encephalomyelitis caused by the virus in cattle were reported. During this period, 30 AKAV isolates were obtained from diseased and sentinel cattle, a piglet and Culicoides biting midges throughout Japan and were subjected to genetic comparison and phylogenetic analysis with previous isolates. In 2007, 2011 and 2013, AKAV belonging to genogroup I was identified in the central nervous systems of calves showing neurological disorders. Notably, a total of 165 cases of bovine encephalomyelitis were reported in 2011 and the isolated viruses from affected animals shared high genetic identities with a South Korean isolate that was associated with a large outbreak in 2010, suggesting some epidemiological linkage between these epizootics. Epizootics of genogroup II were observed in 2008 and 2010, but bovine post‐natal encephalomyelitis cases rarely occurred. Our findings suggest that the frequent incursion of genogroup I isolates has increased the frequency of post‐natal encephalomyelitis cases in Japan in recent years. Infection by genogroup I virus was also identified in piglets with neurological disorders or congenital malformations in 2011 and 2013. The aetiological role of AKAV in pigs should be elucidated in the future. [ABSTRACT FROM AUTHOR]

Schmallenberg virus (SBV) and Akabane virus (AKAV) are teratogenic Simbu serogroup Orthobunyaviruses. Embryonated chicken egg models (ECE) have been used to study the pathogenicity and teratogenicity of Simbu viruses previously, however to date no such studies have been reported for SBV. Hence, the aims of this study were to investigate if ECE are susceptible to experimental SBV infection, and to evaluate the pathogenicity and teratogenicity of SBV and AKAV in ECE models. Two studies were conducted. In Study A, SBV (10 6.4 TCID 50 ) was inoculated into the yolk-sac of 6-day-old and 8-day-old ECEs. In Study B, SBV and AKAV were inoculated into 7-day-old ECEs at a range of doses (10 2.0 –10 6.0 TCID 50 ). ECE were incubated at 37 °C until day 19, when they were submitted for pathological and virological examination. SBV infection in ECE at 6, 7 and 8 days of incubation resulted in stunted growth and musculoskeletal malformations (arthrogryposis, skeletal muscle atrophy, contracted toes, distorted and twisted legs). Mortality was greater in embryos inoculated with SBV (31%) compared to AKAV (19%), ( P <  0.01), suggesting that SBV was more embryo-lethal. However, embryos infected with AKAV had a significantly higher prevalence of stunted growth ( P  < 0.05) and musculoskeletal malformations ( P  < 0.01), suggesting that AKAV was more teratogenic in this model. These studies demonstrate for the first time that the ECE model is a suitable in vivo small animal model to study SBV. Furthermore, these results are consistent with the clinico-pathological findings of natural SBV and AKAV infection in ruminants. [ABSTRACT FROM AUTHOR]

The present study was aimed at the detection and describing the lesions of akabane virus in foetal and new-born calves tissues using immunohistochemical and immunofluorescence techniques. Akabane virus lesions were evaluated in 12 foetuses and three new-born calves using serological and pathological methods and immunohistochemistry and immunofluorescence. Macroscopically, prominent arthrogryposis and hydranencephaly (A-H syndrome) were the main symptoms. At the histopathological examination, lesions were especially localised in the midbrain, pons, and medulla oblongata in the central nervous system (CNS) in calves naturally infected with akabane virus. In these areas, degenerative and necrotic neurons were observed. There was prominent mononuclear infiltration in perivascular areas. While akabane virus antigen was only detected in brain using immunofluorescence, immunohistochemistry against akabane virus yielded positive antigenic reactions in the cerebrum, cerebellum, liver, spleen and kidneys. In addition to these findings, there was a relationship between akabane virus infection and neurofilament (NF), glial fibrillary acidic protein (GFAP), and N-methyl-D-aspartate receptor (NMDAR) immunoreaction in astrocytes and neurons.

We previously generated a recombinant reporter Akabane virus expressing enhanced green fluorescence protein (eGFP-AKAV), with an artificial S genome encoding eGFP in the ambisense RNA. Although the eGFP-AKAV was able to detect infected cells in in vivo histopathological study, its fluorescent signal was too weak to apply to in vivo imaging study. Here, we successfully generated a modified reporter, eGFP/38-AKAV, with 38-nucleotide deletion of the internal region of the 5′ untranslated region of S RNA. The eGFP/38-AKAV expressed higher intensity of eGFP fluorescence both in vitro and in vivo than the original eGFP-AKAV did. In addition, eGFP/38-AKAV was pathogenic in mice at a comparable level to that in wild-type AKAV. In the mice infected with eGFP/38-AKAV, the fluorescent signals, i.e., the virus-infected cells, were detected in the central nervous system using the whole-organ imaging. Our findings indicate that eGFP/38-AKAV could be used as a powerful tool to help elucidate the dynamics of AKAV in vivo.

Culicoides biting midges, small hematophagous dipterans, are the demonstrated or putative vectors of multiple arboviruses of veterinary and public health importance. Despite its relevance in disease spread, the ceratopogonid genus Culicoides is still a largely neglected group of species, predominantly because the major human-affecting arboviruses are considered to be transmitted by mosquitoes. However, when a pathogen is detected in a certain vector species, a thorough search for further vectors often remains undone and, therefore, the relevant vector species may remain unknown. Furthermore, for many hematophagous arthropods, true vector competence is often merely suspected and not experimentally proven. Therefore, we aim to illuminate the general impact of Culicoides biting midges and to summarize the knowledge about biting midge-borne disease agents using the order Bunyavirales, the largest and most diverse group of RNA viruses, as an example. When considering only viruses evidentially transmitted by Culicoides midges, the Simbu serogroup (genus Orthobunyavirus) is presumably the most important group within the virus order. Its members are of great veterinary importance, as a variety of simbuviruses, e.g., the species Akabane orthobunyavirus or Schmallenberg orthobunyavirus, induces severe congenital infections in pregnant animals. The major zoonotic representative of this serogroup occurs in South and Central America and causes the so-called Oropouche fever, an acute febrile illness in humans.

This study was carried out to explore serological and molecular features of Akabane virus (AKAV) in sheep flocks with abortion problems and determine the potential role of Culicoides spp. in the transmission of AKAV. For this purpose, EDTA whole blood (n = 301), sera (n = 301) and aborted foetuses samples (n = 87) were obtained from epidemiologically independent flocks (n = 87) in the Mediterranean region of Turkey during the months of October 2015 and January 2016. Culicoides spp. were trapped from October to November 2015. A commercial competitive ELISA kit was used for the detection of AKAV anti-G1 antibodies in the sera samples. Real-time reverse-transcriptase PCR was used to detect viral RNA in EDTA whole blood, aborted foetuses and Culicoides samples. Genetic characterization of the local AKAV field isolates was conducted by sequencing the S segment of AKAV. Antibodies against AKAV were detected in 135 (44.9%) of 301 animals. Among the 87 flocks, 68 (78.2%) had one or more seropositive animals. Viral RNA was detected in 11 of the 87 aborted foetuses. Furthermore, real-time RT-PCR detected positive viral RNA in Culicoides midges. AKAV RNA was not detected in EDTA whole blood samples. Phylogenetic analysis showed that the field isolates of AKAV obtained in this study clustered within genogroup Ib. The sequence analysis of the mitochondrial cytochrome oxidase subunit I gene of Culicoides spp. showed that the species of Culicoides in AKAV-positive pools was Culicoides imicola . The results of this study showed that AKAV infection plays a role in abortion cases of sheep in the Mediterranean region of Turkey. Therefore, a control program is needed against to AKAV infection. [ABSTRACT FROM AUTHOR]

Aim: The study was conducted in Basrah, Iraq, to diagnose congenital arthrogryposis-hydranencephaly syndrome caused by Akabane virus (AKAV) in calves. Materials and Methods: Affected animals (42 calves) are about 2-27 days old from both sexes show signs of arthrogryposis and hydranencephaly. Eight clinically healthy newborn calves were considered as controls. Diagnosis of AKAV was confirmed using a competition enzyme-linked immunosorbent assay test. Results: Results show that all affected calves were found seropositive. Furthermore, a significant increase in total leukocyte count in diseased calves due to a significant increase in the absolute lymphocyte number indicated in affected calves than in controls. Moreover, a significant increase in sedimentation rate of erythrocytes was also encountered in diseased calves than in controls. In addition, a significant increase in haptoglobin level and fibrinogen was also detected. Conclusion: Diagnosis of AKAV infection of Basrah Governorate, Iraq, will provide useful epidemiological information for cattle and other domesticated animals. Therefore, abortion could be prevented and controlled. [ABSTRACT FROM AUTHOR]

Akabane disease is a viral disease transmitted by biting midges and can cause teratogenic malformations in cattle, sheep and goats. Abortion outbreaks associated with arthrogryposis and cerebellar hypoplasia in two epidemiologically independent flocks were reported in the Mediterranean region of Turkey in 2015. Phylogenetic analysis based on nucleocapsid (N) gene sequences showed that the field isolates presented here belong to the genogroup Ib. The akabane virus (AKAV) field isolates analysed in this study displayed 6 new amino acid substitutions in N and non-structural protein chains compared with those of AKAV strains belonging to genogroup Ib. To the best of our knowledge, this is the first report on the presence of the AKAV genogroup Ib in Turkey. [ABSTRACT FROM AUTHOR]

Akabane virus (AKAV) is a member of the Simbu serogroup, classified in the genus Orthobunyavirus , family Bunyaviridae . AKAV infection can cause abortion, stillbirth, and congenital arthrogryposis and hydranencephaly in cattle and sheep. The distribution and prevalence of AKAV infection in China is still unknown. A total of 2731 sera collected from 2006 to 2015 in 24 provinces of China from cattle, sheep, goats and yak were examined by serum neutralisation test. The overall seroprevalence rates for AKAV antibodies were 21.3% in cattle (471/2215) and 12.0% (17/142) in sheep or goats, and 0% in yak (0/374). The results indicated widespread AKAV infection in China among cattle and sheep but yak appear to have a low risk of infection. Using a selection of 50 AKAV-positive and 25 AKAV-negative cattle sera, neutralisation tests were also conducted to detect antibodies to several other Simbu serogroup bunyaviruses and closely related Leanyer virus. Although inconclusive, the data suggest that both Aino virus and Peaton virus, which have been reported previously in Japan and Korea, may also be present in cattle in China. [ABSTRACT FROM AUTHOR]

To identify the causative agents in 3 large-scale outbreaks of encephalitis and death among farmed bamboo rats ( Rhizomys pruinosus ). The routine bacterial culture and identification were performed. There were no significant pathogenic bacteria isolated from the brain, heart, liver, spleen, lung, or kidney of diseased bamboo rats. Using PCR-based methods, we excluded the following as causative agent: pox virus, herpesvirus, adenovirus, lymphocytic choriomeningitis virus, rabies virus, and sendai virus. Furthermore, the homogenate from the diseased bamboo rats was subjected to viral metagenomic analysis which revealed 48506 filtered viral reads annotated to Akabane virus (AKAV) with >75% nucleotide identity, suggesting the presence of AKAVs in bamboo rats. Five novel AKAV isolates were successfully isolated and characterized. Furthermore the newly isolated AKAV isolate was used to demonstrate that it can reproduce the severe encephalitic and pneumonic disease in bamboo rats and mice. The findings add to the better understanding of AKAV epidemiology and to the prevention and control of Akabane diseases in China. [ABSTRACT FROM AUTHOR]

Akabane virus (AKAV) and Schmallenberg virus (SBV) are members of the genus Orthobunyavirus, which are transmitted by arthropod vectors with a broad cellular tropism in vitro as well as in vivo. Both AKAV and SBV cause arthrogryposishydranencephaly syndrome in ruminants. The main cellular receptor and attachment factor for entry of these orthobunyaviruses are unknown. Here, we found that AKAV and SBV infections were inhibited by the addition of heparin or enzymatic removal of cell surface heparan sulfates. To confirm this finding, we prepared heparan sulfate proteoglycan (HSPG)-knockout (KO) cells by using a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 system and measured the quantities of binding of these viruses to cell surfaces. We observed a substantial reduction in AKAV and SBV binding to cells, limiting the infections by these viruses. These data demonstrate that HSPGs are important cellular attachment factors for AKAV and SBV, at least in vitro, to promote virus replication in susceptible cells. [ABSTRACT FROM AUTHOR]

Summary In 2010, there was a large-scale outbreak of bovine encephalomyelitis in Korea, and 15 new strains of Akabane virus (AKAV) were isolated. To identify the pathogenicity of one of these strains, we infected adult goats with AKAV-7 via different routes. Twenty-five female goats were used in this study and were divided into five groups: intracerebral (IC) and intrasubarachnoid (IS) viral inoculation ( n = 8 each), intravenous (IV) inoculation ( n = 4), and vaccinated before IV inoculation ( n = 4), in addition to a negative control animal. All animals inoculated with AKAV-7 had AKAV-neutralizing antibodies at 6–8 days post infection (dpi). During the experimental period, infected animals showed no clinical signs. In the IC group, 5/8 goats had non-suppurative encephalomyelitis affecting the cerebrum. Virus S RNA segments were detected in nearly all areas of the brain. In the IS group, 3/8 goats had encephalomyelitis affecting the cerebrum, cerebellum and spinal cord. At 7 and 21 dpi, virus S RNA segments were found mostly in the spinal cord, especially around the area of injection (L5–L6). Antibody titres in the serum of the vaccinated group had an early onset and slightly increased titre compared with the IV group. Histopathologically, there were no obvious lesions in the central nervous tissues in the vaccinated group, while one of four goats in the IV group showed encephalomyelitis in the parietal lobe of the cerebrum. The newly isolated AKAV-7 can cause encephalomyelitis in goats after experimental injection. The attenuated AKAV vaccine currently used in Korea may provide partial protective immunity against AKAV-7 infection, but the real effect of the vaccine requires further investigation in goats. [ABSTRACT FROM AUTHOR]

We isolated an arbovirus from bovine blood in Indonesia. The arbovirus was obtained from the plasma of a cow showing no clinical symptoms in West Java in February 2014, and was identified as Akabane virus (AKAV) by AKAV-specific RT-PCR and subsequent sequence analysis. Phylogenetic analysis based on partial S segment indicated the AKAV isolate, WJ-1SA/P/2014, was most closely related with two isolates from Israel and Turkey reported in 2001 and 2015, respectively, and that WJ-1SA/P/2014 isolate belongs to AKAV genogroup Ib. This is the first isolation of AKAV from Indonesia. [ABSTRACT FROM AUTHOR]

The biological function of a nonstructural protein, NSm, of Akabane virus (AKAV) is unknown. In this study, we generated a series of NSm deletion mutant viruses by reverse genetics and compared their phenotypes. The mutant in which the NSm coding region was almost completely deleted could not be rescued, suggesting that NSm plays a role in virus replication. We next generated mutant viruses possessing various partial deletions in NSm and identified several regions critical for virus infectivity. All rescued mutant viruses produced smaller plaques and grew inefficiently in cell culture, compared to the wild-type virus. Interestingly, although the pathogenicity of NSm deletion mutant viruses varied in mice depending on their deletion regions and sizes, more than half the mice died following infection with any mutant virus and the dead mice exhibited encephalitis as in wild-type virus-inoculated mice, indicating their neuroinvasiveness. Abundant viral antigens were detected in the brain tissues of dead mice, whereas appreciable antigen was not observed in those of surviving mice, suggesting a correlation between virus growth rate in the brain and neuropathogenicity in mice. We conclude that NSm affects AKAV replication in vitro as well as in vivo and that it may function as a virulence factor. [ABSTRACT FROM AUTHOR]

Akabane virus (AKAV), an arthropod-transmitted bunyavirus, is a major cause of congenital abnormalities and encephalomyelitis in ruminants. In 2010, there was a major outbreak of encephalomyelitis in Korea and fifteen AKAV strains, including AKAV-7, were isolated from cows. To identify the neuropathogenicity of AKAV-7, we performed experimental infection of cows. Six-month-old female Korean Holstein dairy cattle were inoculated with AKAV-7 by various routes, including intracerebral (IC), intrasubarachnoid space (IS), subcutaneous (SC) and intravenous (IV); a separate group was vaccinated before intravenous infection. Five of the six cows in the IC group and two of the six cows in the IS group showed clinical signs such as locomotor ataxia and paralysis of the hind limbs. Three of six cows died after IC infection 9-12 days post infection (dpi). Histopathologic changes such as nonsuppurative encephalomyelitis were confirmed in various parts of the central nervous system in the IC, IS and SC groups. Early onset of neutralizing antibodies in the serum and lower viral mRNA levels in the peripheral blood mononuclear cells (PBMCs) and various tissues in the vaccinated group was noticeable compared to the unvaccinated group (IV group). We suggest that the AKAV vaccine currently used in Korea may be partially effective for protection against AKAV-7 in cows. [ABSTRACT FROM AUTHOR]