Virus akabane

Vaccines are used to control disease due to Akabane virus in Japan and Schmallenberg virus in Europe. Akabane and some of the related Simbu serogroup viruses, including Schmallenberg, are insect-transmitted viruses that cause congenital abnormalities of the CNS and musculoskeletal system in ruminants.

Disease due to Akabane virus has been recognized in Australia, Israel, Japan, and Korea, usually at the margins of endemic areas. Schmallenberg virus caused an outbreak of disease associated with congenital defects across the European continent when it first emerged in The disease affects fetuses and neonates of cattle, sheep, and goats, mostly after in utero exposure.

The causal agent of Akabane infection, Akabane virus, is an orthobunyavirus and member of the Simbu serogroup of the family Peribunyaviridae , order Bunyavirales. It is spread by biting midges Biting Midges Culicoides sensitivity in a horse.

The most common biting midges are Culicoides spp. They are associated with Infections with the Simbu serogroup viruses have been identified in all domestic ruminant species cattle, sheep, goats , horses, buffalo, deer, camelids, and pigs in endemic areas. In Africa, antibodies have been detected in a wide range of native wildlife.

Akabane virus has been widely detected in the tropical, subtropical, and adjacent temperate regions of Africa, the Middle East, throughout Asia, and south to Australia. A number of other viruses belonging to the Simbu serogroup have not usually been associated with disease but have a similar distribution.

Schmallenberg virus was first discovered in when it emerged in Western Europe, spreading throughout Europe, to the UK, and to the Scandinavian countries. None of the Simbu serogroup viruses that affect animals have been detected in North America, although Oropouche virus , which causes a febrile illness in humans, is found in South America and the Caribbean.

Akabane and Schmallenberg virus are members of the Simbu antigenic group in the Orthobunyavirus genus of the family Peribunyaviridae , order Bunyavirales. The Simbu serogroup viruses are usually transmitted very efficiently by their insect vectors, which are predominantly Culicoides spp. They are true arboviruses—that is, after the insect takes a blood meal from its mammalian host, the virus replicates in the insect and, after an incubation period of about 8—10 days, is excreted in the saliva when the insect takes another blood meal.

Although there can be limited animal to animal transmission of some of these viruses, they are mostly dependent on spread by their insect vectors. Consequently, the geographic distribution of these viruses is exclusively defined by the habitat and range of the biting midge. In these endemic areas, most herbivores become infected at an early age and develop a long-lasting immunity by the time of breeding.

Thus, congenital abnormalities are seldom seen. However, under favorable environmental conditions, such as an extended, humid summer, the vector and hence the virus may spread beyond its usual range into new areas, and outbreaks of congenital infection may be expected.

These outbreaks usually occur at the northern or southern limits of the vector distribution or in areas of higher altitude. Similarly, pregnant ruminants from virus- and vector-free areas that are moved to virus-infected areas are at risk. The midges that have been associated with the transmission of Schmallenberg virus in Europe have a greater tolerance to cooler temperatures, resulting in more northern limits to spread of the virus and detection of low-level transmission as temperatures rise soon after winter.

The incidence of disease induced by Akabane and Schmallenberg viruses, is influenced by the time of gestation at which infection occurs and by the strain of virus. Some strains of Akabane virus produce a very low incidence of abnormalities In sheep and goats, disease is seen after infection of susceptible, pregnant animals, but the distinct sequential manifestation of different abnormalities seen in cattle does not occur because of the shorter period of gestation and the shorter period of susceptibility.

Most abnormalities develop after infection between days 28—56 of gestation. Few, if any, abnormalities are seen after infection at other times. However, it is not known whether infection in large or small ruminants very early in gestation results in lethal infection, with abortion of the fetus. The clinical signs and pathology of Akabane virus infection depend on the species of animal and time of infection. In a herd of cattle with an extended or year-round calving period, the full range of abnormalities may be seen.

Calves infected late in pregnancy may be born alive but unable to stand and may have a flaccid paralysis of the limbs, or may be uncoordinated. Those infected earlier — days of gestation have rigid fixation of limbs, usually in flexion arthrogryposis , and sometimes also torticollis, kyphosis, and scoliosis. These abnormalities usually cause dystocia and can result in severe obstetric complications, sometimes resulting in infertility and even death of cows. The GXDH 01 strain was avirulent or, at most, caused slightly transient weight loss in mice.

Jeong et al performed experimental inoculation of AKAV-7 on goats via different routes. During the experimental period, infected goats showed no clinical signs, but some animals showed encephalomyelitis on histopathological examination after IC and IV inoculation and lesions in the brain and spinal cord after IS inoculation [ 9 ]. The pathogenicity of reassortment AKAV cause attenuate in infection mice or goats.

Since GXDG 01 was isolated from asymptomatic sentinel goats of 8 months old, its pathogenicity in sheep and cattle remains unknown. Thus, further study is necessary to evaluate the pathogenicity. The strain was further determined to be a reassortant virus that contained L segments from an isolate of OBE-1 originating from Japan. Further experimental studies should be performed to confirm the biological characteristics of GXDH 01, especially its pathogenicity in sheep and cattle.

The animal experiments were approved and performed in accordance with the animal ethics guidelines and approved procedures of Guangxi Veterinary Research Institute. We are grateful to Associate Prof. National Center for Biotechnology Information , U. J Vet Med Sci. Published online Aug 5. Author information Article notes Copyright and License information Disclaimer. Received Oct 11; Accepted Jul This article has been cited by other articles in PMC.

Associated Data Supplementary Materials Supplement table. Keywords: Akabane virus, complete open reading frame, goat, phylogenetic analysis. Table 1. Distributions of the seroprevalence of Akabane virus in Guangxi province. Open in a separate window. Table 2. The primers amplification the S, M and L segments of Akabane virus isolated from goat, China used in this study. Supplementary Material Supplement table: Click here to view. Acknowledgments We are grateful to Associate Prof. Al-Busaidy S.

Prevalence of neutralising antibodies to Akabane virus in the Arabian peninsula. Neutralising antibodies to Akabane virus in free-living wild animals in Africa. Health Prod. EIhassan A. A serological survey of akabane virus infection in cattle in Sudan. ISRN Vet.

Forman S. Climate change impacts and risks for animal health in Asia. Gard G. Bluetongue virology and serology. Haughey K. Akabane disease in sheep. Inaba Y. Letter: Akabane disease: epizootic abortion, premature birth, stillbirth and congenital arthrogryposis-hydranencephaly in cattle, sheep and goats caused by Akabane virus. It is spread by biting midges Culicoides spp. Akabane virus infection is associated with abortion, stillbirth and congenital abnormalities such as arthrogryposis and hydranencephaly however, the severity of clinical signs and pathology are variable depending on the species of animal and time of infection.

Disease due to Akabane virus is mostly observed in cattle due to the long period of gestation and breeding throughout the year. For specific information about your submission please contact Customer Service. Home Services Laboratory services Veterinary testing.