Characterization and reverse genetic establishment of cattle derived Akabane virus in China

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.

Antibodies to Bluetongue, Akabane and Schmallenberg viruses in native dromedary camels in Turkey

Sera from 86 Turkish native camels from seven provinces in Turkey were collected and tested for specific antibodies to Bluetongue virus (BTV), Akabane virus (AKAV) and Schmallenberg virus (SBV) using ELISA. The BTV, AKAV and SBV antibodies were found in 53.5%, 51.2% and 15.1%, respectively. Furthermore, the seropositivity for multiple infection was the highest for dual infection with AKAV and BTV (25.6%), followed by triple seropositivity (9.3%). These findings indicated that BTV, AKAV and SBV circulate in camels in Turkey at a relatively high rate, and that an active surveillance program is needed for the management and tracing the dynamics of these infections in the Turkish camel population.

Simbu Viruses’ Infection of Livestock in Israel—A Transient Climatic Land

Important lessons have been learned by the Israeli veterinary community regarding Simbu serogroup viruses infections. This serogroup of viruses might cause the births of neonatal malformation in susceptible ruminant’s populations. Until 2012, only Akabane virus was connected with the births of malformed ruminants in Israel. However, serological and genomic detection tests, coupled with viral isolations, revealed that more than a single Simbu serogroup serotype could be present concurrently in the same farm or even in the same animal. From 2012 to date, Aino, Shuni, Shamunda, Satuperi, Peaton, Schmallenberg, and Sango viruses have been found in Israel either by serological or genomic investigation. Israel is located in the Eastern Mediterranean Basin, a terrestrial and climatic bridge between the three old continents. The Eastern Mediterranean shores benefit from both the tropical/subtropical and the continental climatic conditions. Therefore, the Eastern Mediterranean basin might serve as an optimal investigatory compound for several arboviral diseases, acting as a sentinel. This review summarizes updated information related to the presence of Simbu serogroup viruses in Israel.

Characterization and Reverse Genetic Establishment of Cattle Derived Akabane Virus in China

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

Complete Genome Sequences of Two Akabane Virus Strains Causing Bovine Postnatal Encephalomyelitis in Japan

ABSTRACT Akabane virus (AKAV) (genus Orthobunyavirus, family Peribunyaviridae) is an arthropod-borne virus that causes congenital abnormalities in ruminants. Here, we report the complete genome sequences of two AKAV strains causing nonsuppurative encephalomyelitis in cattle by postnatal infection in Japan.

Comparative evaluation of two commercial ELISA kits for detection of antibodies against Akabane virus in cattle serum

Background Akabane disease (AD), a barrier to international trade for endemic areas with far economic impact on the countries, is caused by Akabane virus (AKAV). Commercial enzyme-linked immunosorbent assay (ELISA) is a commonly used diagnostic technique for AKAV infection, including the IDEXX and IDVET ELISA kits. However, the comparative evaluation of the IDEXX and IDVET ELISA kits has not been published. The object of this study was to evaluate the test performance of the two commercial ELISA kits in detecting serum anti-AKAV antibodies in cattle. Results With virus neutralization test (VNT) as the “relative gold standard”, the diagnostic sensitivity (DSe) was 80.39% (123/153) and 93.46% (143/153) for the IDEXX and IDVET ELISA kit, when suspect samples were included. The diagnostic specificity (DSp) for the IDEXX and IDVET ELISA kit was 93.48% (502/537) and 82.31% (442/537), respectively. Conclusion Both of the tested ELISA kits could be applied to detect antibodies against AKAV in cattle serum. The IDVET ELISA kit had a higher DSe. The IDEXX ELISA kit possessed the higher DSp. These results have important implications if the kits are used to screen herds or individual cattle in surveillance programs, or at border crossings for import-export inspection and quarantine.

Congenital abnormalities and arthrogryposis in newly born lambs in Al Muthanna province Iraq. Suspicion of Akabane virus infection

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.

Generation of a GFP Reporter Akabane Virus with Enhanced Fluorescence Intensity by Modification of Artificial Ambisense S Genome

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.