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Schmallenberg virus (SBV) is a newly emerged virus responsible for an acute non-specific syndrome in adult cattle including high fever, decrease in milk production and severe diarrhea. It also causes reproductive problems in cattle, sheep and goat including abortions, stillbirths and malformations. The role of pigs in the epidemiology of SBV has not yet been evaluated while this could be interesting seen their suggested role in the epidemiology of the closely related Akabane virus. To address this issue, four 12 week old seronegative piglets were subcutaneously infected with 1 ml of SBV infectious serum (FLI) and kept into contact with four non-infected piglets to examine direct virus transmission. Throughout the experiment blood, swabs and feces samples were collected and upon euthanasia at 28 dpi different organs (cerebrum, cerebellum, brain stem, lung, liver, iliac lymph nodes, kidney and spleen) were sampled. No clinical impact was observed and all collected samples tested negative for SBV in rRT-PCR. Despite the absence of viremia and virus transmission, low and short lasting amounts of neutralizing antibodies were found in 2 out of 4 infected piglets. The limited impact of SBV infection in pigs was further supported by the absence of neutralizing anti-SBV antibodies in field collected sera from indoor housed domestic pigs ( n = 106). In conclusion, SBV infection of pigs can induce seroconversion but is ineffective in terms of virus replication and transmission indicating that pigs have no obvious role in the SBV epidemiology.

A cross-sectional survey was carried out in ten states in Sudan to determine seroprevalence and to assess risk factors associated with Akabane virus (AKAV) infection in dairy herds. Serum samples were collected from a total of 361 dairy cattle and tested for antibodies against AKAV using ELISA. The prevalence rates of AKAV antibodies in cattle varied between 69.6% in Khartoum state and 3.3% in Sennar State with an overall prevalence rate of 29.4%. The prevalence rates of AKAV antibodies were significantly associated with breed being high in crossbred (39.9%; P<0.001); female sex (33%; P<0.001), and animals in the age group of 2-3 years old (45.3%; P<0.001). Akabane virus antibodies prevalence was also highly associated with locality (P<0.001); season being high in winter season (58.1%; P<0.001); and animals raised under intensive management system (37%; P<0.001). Among 68 cases suffering from reproductive (abortion and infertility) problems the prevalence rate of AKAV antibodies in animals with infertility problem (76.2%; P<0.03) was significantly higher than in animals with abortion (48.9%). The study revealed that AKAV infection is highly prevalent in dairy cattle in Sudan and this calls for control strategy to be implemented.

The entry mechanisms of Akabane virus (AKAV), Bunyaviridae family, have not yet been determined. In this study, chemical inhibitors were used to analyze endocytic mechanisms during AKAV infection of mammalian cell lines. The analyses using drug treatments followed by quantitative measurement of viral RNA and N protein revealed that AKAV enters non-bovine-derived cell lines (Vero, HmLu-1 and BHK cells) in a manner indicative of clathrin endocytosis. By contrast, AKAV infection in bovine-derived cell lines (LB9.K and MDBK cells) is independent of this pathway. Further analyses indicated that AKAV entry into bovine cell lines involves a non-clathrin, non-caveolae endocytic pathway that is dependent on dynamin. We conclude that although both cell types require a low pH for AKAV penetration, AKAV utilizes alternative entry pathways into mammalian cell lines.

In 2011, Schmallenberg virus (SBV), a novel member of the Simbu serogroup, genus Orthobunyavirus, was identified as the causative agent of a disease in ruminants in Europe. Based on the current knowledge on arthropods involved in the transmission of Simbu group viruses, a role of both midges and mosquitoes in the SBV transmission cycle cannot be excluded beforehand. The persistence of SBV in mosquitoes overwintering at SBV-affected farms in the Netherlands was investigated. No evidence for the presence of SBV in 868 hibernating mosquitoes (Culex, Anopheles, and Culiseta spp., collected from January to March 2012) was found. This suggests that mosquitoes do not play an important role, if any, in the persistence of SBV during the winter months in northwestern Europe.

To detect Schmallenberg virus (SBV) infections in ruminants and to perform SBV epidemiological studies a cost-effective serological test is required. For these purposes an indirect whole virus Enzyme-linked Immunosorbent Assay (ELISA) for detection of SBV specific antibodies in ruminant blood samples was developed. Schmallenberg virus antigen was produced by propagation on Vero cells, partly purified and coated onto ELISA plates. The indirect ELISA procedure included the subsequent incubation of diluted samples, protein-G-HRP conjugate and TMB substrate solution. Net Optical Densities (OD) values were calculated and expressed as a sample to positive percentage (S/P%) by comparison of the average net OD with the OD of the positive control. Validation of this assay was performed using 633 samples from SBV-free sheep, goats and cattle, and 141 samples from SBV suspect ruminants. The diagnostic specificity was 98.8%. Test results of 86 ruminant serum samples using both the SBV-ELISA and an SBV virus neutralization test (VNT), designated as the gold standard serological test for SBV, showed good correlation: at an S/P cut-off of 15% only one VNT positive sample tested negative in the SBV ELISA. The diagnostic sensitivity of the ELISA, relative to the VNT, was 98.8% (95% CI: 93.3-100.0%). The ELISA showed a high repeatability (cv=6.5%) and reproducibility (100% agreement). It was concluded that this ELISA is a suitable test method for the detection of SBV antibodies in sera from cows, sheep and, possibly, goats.

Since a large number of Akabane and bovine ephemeral fever (BEF) infection occurred in the southern part of Korea in 2010, recent information about seroprevalence of Akabane virus (AKAV) and bovine ephemeral fever virus (BEFV) has been required for preventing both diseases. In this study, serological assay against AKAV and BEFV using virus neutralization assay was conducted using 1,743 bovine sera collected from Namwon, Miryang, Yeongju and Uljin which located in Southern part of Korea from March to May in 2012. The overall seropositive rates for AKAV and BEFV were found to be 49.8% and 1.2%, respectively. The regional distribution of seroprevalence for AKAV ranged from 18.1% to 63.7%. Seroprevalences of AKAV were 63.7% in Miryang, 62.3% in Uljin, 50.7% in Namwon, and 18.1% in Yeongju. The seropositive rates for AKAV in southern part of Korea were higher than the annual average at the national level. On the other hand, seropositive rates of BEFV in four regions were from 0.3 to 3.1%. In detail, regional seroprevalences were 3.1% in Miryang, 2.0% in Uljin, and 1.7% in Yeongju, and 0.3% in Namwon. Even only one year after massive outbreaks, overall seropositive rates were very low, similar to the annual average at the nation level. This result indicates that many number of cattle infected with BEFV may be replaced by new born calf or cattle in farm may not be immunized with vaccines. To prevent another epidemic, a national wide warning should be issued and more aggressive control measure must be implied. Recent global warming phenomenon could lead to more vigorous activity of haematophagous vectors and it is possible that arboviral diseases such as AKAV and BEFV are increased. Therefore, continuous sero-monitoring and extensive vaccination combined with control of haematophagous vectors are important to effectively prevent and control diseases caused by AKAV and BEFV.

The article describes the characteristics of Schmallenberg and Akabane viruses that cause disease in cattle, sheep and goats. Сlinical symptoms of the diseases are described. The measures for the prevention, control and eradication of Schmallenberg and Akabane viruses are discussed. Despite the relationship of Schmallenberg and Akabane viruses and a similarity of the clinical picture and pathological changes, there are also differences. The first disease is more severe in sheep and goats than in bovine (cattle), with the viremia occurred at 1-4 days and 1-9 days (mostly 4-5 days) for Schmallenberg and Akabane viruses, respectively. Under Akabane virus infection, an encephalitis is observed in adult cattle, whereas such cases are not yet registered under the Schmallenberg disease. The authors have developed the test systems for detection of Akabane virus RNA by polymerase chain reaction and Schmallenberg virus genome by reverse transcription—polymerase chain reaction in real time (RT-PCR). For Akabane and Smallenberg viruses RNA detecting, a real time reverse transcriptase PCR-based tests have been developed by the authors.

The article describes the characteristics of Schmallenberg and Akabane viruses that cause disease in cattle, sheep and goats. Сlinical symptoms of the diseases are described. The measures for the prevention, control and eradication of Schmallenberg and Akabane viruses are discussed. Despite the relationship of Schmallenberg and Akabane viruses and a similarity of the clinical picture and pathological changes, there are also differences. The first disease is more severe in sheep and goats than in bovine (cattle), with the viremia occurred at 1-4 days and 1-9 days (mostly 4-5 days) for Schmallenberg and Akabane viruses, respectively. Under Akabane virus infection, an encephalitis is observed in adult cattle, whereas such cases are not yet registered under the Schmallenberg disease. The authors have developed the test systems for detection of Akabane virus RNA by polymerase chain reaction and Schmallenberg virus genome by reverse transcription—polymerase chain reaction in real time (RT-PCR). For Akabane and Smallenberg viruses RNA detecting, a real time reverse transcriptase PCR-based tests have been developed by the authors.

In 2011, Schmallenberg virus (SBV), a novel member of the Simbu serogroup, genus Orthobunyavirus, was identified as the causative agent of a disease in ruminants in Europe. Based on the current knowledge on arthropods involved in the transmission of Simbu group viruses, a role of both midges and mosquitoes in the SBV transmission cycle cannot be excluded beforehand. The persistence of SBV in mosquitoes overwintering at SBV-affected farms in the Netherlands was investigated. No evidence for the presence of SBV in 868 hibernating mosquitoes (Culex, Anopheles, and Culiseta spp., collected from January to March 2012) was found. This suggests that mosquitoes do not play an important role, if any, in the persistence of SBV during the winter months in northwestern Europe.

The embryonated chicken egg (ECE) provides a convenient, space-saving incubator for the cultivation of many kinds of animal viruses where the egg can be easily observed for viral replication throughout the development of the chicken embryo. Within the family Bunyaviridae , the embryonated egg has been used as a host system for many viruses such as Rift Valley fever virus and Akabane virus . The current study was conducted to determine the cultivation of Crimean-Congo hemorrhagic fever virus (CCHFV) in ECE. Four-day-old eggs were infected with CCHFV via the yolk sac route and harvested embryonic tissues and amino-allantoic fluid (AAF) that were used for virus passage and viral RNA (vRNA) detection. Quantification of vRNA copies was performed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Our study indicated that CCHFV caused the death of the embryonated egg in a dose-dependent manner and the 50% egg infectious dose (EID 50 ) was determined to be 6.47 × 10 5 copies/egg. CCHFV replicated and passaged well in the egg and high viral loads were detected both in embryonic tissue (10 9–10 copies/g) and AAF (10 7–9 copies/ml) of the embryonated egg. Thus, ECE could be used for viral cultivation and preservation, and as a potential host infection model for the study of the pathogenesis of CCHFV.

The aim of this study is to investigate the prevalence of some diseases in domestic livestock in two protected areas in Saudi Arabia where gazelles have been reintroduced. King Khalid Wildlife Research Centre (KKWRC) was established in 1986 to breed and undertake scientific research on Saudi wildlife for reintroduction purposes. Mountain gazelles (Gazella gazella) were reintroduced to the Ibex Reserve 150 km south of Riyadh in central Saudi Arabia, which supports viable population of wild ibex. Sand gazelles (Gazella marica), Mountain gazelles and Arabian oryx (Oryx leucoryx) were reintroduced to Uruq Bani Ma’arid (UBM) Reserve in the Al Rub al Khali desert. Domestic livestock (camels, sheep and goats) owned by local people use the Reserves and the area surrounding for grazing and there is contact between these animals and reintroduced wildlife. Two surveys have been carried out at each Reserve. Serum samples collected from 1012 camel, sheep and goats were screened for some viral, bacterial and parasitic diseases that are of particular concern in Saudi Arabia. The results show the presence of antibodies against tuberculosis, brucellosis, bluetongue virus, akabane virus, contagious pustular dermatitis and toxoplasmosis. The Suadi Wildlife Authority (SWA) coordinated with the Ministry of Agriculture and established monitoring and remedial programmes to control diseases reported in the present study. The epidemiological significance, of the study, to wildlife was discussed. Key words: Domestic livestock, serosurvaillence, Ibex Reserve, Uruq Bani Ma’arid, Saudi Arabia

A novel orthobunyavirus, named "Schmallenberg virus" (SBV), was first detected in the blood of cattle at the end of the summer in Germany in 2011, and subsequently in late autumn from the brain of a stillborn malformed lamb in The Netherlands. Full genome sequences, including 5' and 3' terminal "panhandle" sequences of the L, M, and S segments of the SBV isolated from lamb brain tissue (named HL1) were determined. In addition, a second SBV strain was isolated from the blood of a dairy cow (named F6) also in The Netherlands. This isolate was passaged on Vero cells, and its genome sequence was determined by next-generation sequencing. Alignments of the two genome sequences revealed 4, 12, and 2 amino acid differences in the open reading frames of the L, M, and S segments, respectively. Eleven of a total of 12 amino acid differences were detected in the M segment encoding the ectodomain of the putative structural glycoprotein Gc. Notably, in the HL1 isolate, positions 737-739 are occupied by isoleucine, arginine, and leucine (IRL), whereas in the majority of other sequenced SBV isolates these positions are occupied by threonine, histidine, and proline, respectively. Moreover, in all sheep, goat, and cattle SBV isolates sequenced and published so far, an IRL sequence was never found. This has brought us to the conclusion that the M segment of the HL1 isolate differed markedly from that of other lamb and cow isolates. Whether this atypical variant resulted from adaptation to the ewe, fetus, or insect vector remains to be investigated.

Akabane virus (AKAV), an orthobunyavirus, is transmitted primarily by biting midges and is widely distributed throughout the world except the Europe. AKAV was first isolated from mosquitoes in Japan (Oya et al., 1961). Although pregnant cows, ewes, and goats infected with AKAV exhibit no clinical signs of disease, in utero infections result in abortion, premature birth, stillbirth, and congenital deformities such as arthrogryposis-hydranencephaly syndrome (Kurogi et al., 1976), causing economic losses in the livestock industry. The live, attenuated vaccine strain, TS-C2, was derived from the OBE-1 strain as a temperature sensitive mutant (Kurogi et al., 1979). Although vaccination has reduced the prevalence of the disease, antigenic and pathogenic variants of AKAV have been isolated (Lee et al., 2002; Ogawa et al., 2007a); for example, a variant Iriki strain was isolated from a calf with nonsuppurative encephalitis and neurological symptoms in Japan (Miyazato et al., 1989) and it shows low antigenic cross-reactivity with the reference strain in neutralization tests (Akashi and Inaba, 1997). Therefore, it is necessary to reconsider the vaccination strategy to effectively control the disease. Here we evaluated characters of a mutant virus with knockout of a nonstructural protein NSs, which acts as type I interferon antagonist and is involved in the regulation of host protein synthesis (Weber et al., 2002), by experimentally infecting pregnant goats. The pregnant goat model might be useful for AKAV studies, as suggested by previous reports of experimental transplacental infection of caprine fetuses (Kurogi et al., 1977).

International audience; AbstractAkabane 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.

ÖZETAkabane infeksiyonu gebe hayvanlarda ve yeni doğanlarda oluşturduğu bozukluklarsonucu önemli ekonomik kayıplara neden olmaktadır. Ülkemiz dahil birçok ülkedebildirilmiştir. Virus, duyarlı konaklar arasında Culicoides spp. türü kan emici sineklerle vevertikal yolla bulaşmaktadır.Bu çalışmada, Marmara bölgesinde bulunan çiftlikler ziyaret edilerek 175 sığır ve 50koyundan EDTA'lı ve antikoagülansız kan alındı. Tuzla ve Hadımköy mezbahalarından 50 sığırve 25 koyundan organ ve kan numuneleri toplandı. Pendik Veteriner Kontrol Enstitüsü'ne veİstanbul Üniversitesi Veteriner Fakültesi Viroloji Anabilim Dalı'na gelen klinik olarak Akabaneşüphesi taşıyan 25 sığır ve 25 koyunun abort ve ölü yavrulardan akciğer, karaciğer, dalak,beyin ve plesanta örnekleri alındı. Kan serumu örnekleri ile yapılan ELISA sonucunda 225 adetsığır serum örneğinden 17 tanesinde (%7,55) seropozitiflik saptandı. Marmara bölgesindebulunan 11 ilden toplanan örneklerde sığırlar için seropozitiflik % 0 ile % 15,68 arasında tespitedildi. Koyun serum örneklerinde herhangi bir seropozitiflik saptanmadı. Akabane şüpheli 25sığır ve 25 koyun abort ve ölü yavrulardan alınan akciğer, karaciğer, dalak, beyin, plasenta ileyapılan real time RT-PCR sonucunda 2 sığır numunesinde akabane virus-RNA'sı saptandı. Buörneklerden 3 kez pasajlanarak yapılan BHK-21 ve VERO hücre kültürü çalışmalarında CPEoluşumu gözlenmedi. Hücre kültürünün real time RT-PCR ve RT-PCR ile incelenmesisonucunda pozitiflik saptanmadı. Mezbahalardan alınan 50 sığır ve 25 koyun organ ve dokuörnekleri ile yapılan real time RT-PCR ve RT-PCR sonucunda da pozitiflik saptanmadı.Sonuç olarak, Akabane infeksiyonu serolojik olarak %7,55 oranında saptanmıştır veülkemiz sığırları açısından risk oluşturmaktadır. Türkiye'de tüm bölgelerde prevalansın ortayaçıkarılmasında ve vektörlerde dikkate alınarak risk analizleri yapılmasında yarar vardır. Buamaçla kolay uygulanabilirliği ve çok sayıda serumun kısa sürede incelenebileceği ELISAtestinin kullanılması ve daha sonra pozitif örneklerin teyit edilmesi için real time RT-PCR ileincelenmesini önermekteyiz. Ayrıca vektör olan sineklerde (Culicoides) virusun bulunmasıklığının da araştırılmasında yarar vardır. ABSTRACTAkabane disease causes economic losses since it triggers serious disorders in peregnantruminants and new borns. It has been reported in many countries including Turkey. TheAkabane virus is transmitted by Culicoides spp. mosquitos between susceptible hosts as weel asvertical transmission.In this study, sampling had been performed from farms in Marmara region and 175 cattleand 50 sheep blood samples both with or without EDTA were collected. Also lung, liver,spleen, brain, plecanta and blood samples were collected from 50 cattle and 25 sheep afterslaughtering in Tuzla and Hadımköy slaughterhouses. In addition, lung, liver, spleen, brain andplacenta samples were taken from 25 cattle and 25 sheep, abortions or dead newborns whichwere brought to Pendik Veterinary Control Institute and Virology Department of IstanbulUniversity, Faculty of Veterinary Medicine, suspected of Akabane disease. In ELISAperformed with collected serum samples, 17 (7.55 %) of the 225 cattle samples were found tobe seropositive. Seropositivity ratio in cattle samples achieved from 11 provinces in Marmararegion was detected between 0% - 15.68%. On the other hand, no seroposivity to Akabane viruswas detected in sheep sera. Akabane virus–RNA was detected in 2 samples (lung, liver, spleen,brain and placenta) taken from 25 cattle and 25 sheep abortions or dead newborns. No CPE wasobserved in VERO and BHK-21 cells when 2 real time RT-PCR positive samples subjected tovirus culture. Also no amplification was detected in these cells by both real time RT-PCR andRT-PCR. In addition, no positivity was detected by real time PCR and RT-PCR in lung, liver,spleen, brain, placenta and blood samples collected from 50 cattle and 25 sheep from Tuzla andHadımköy slaughterhouses.In conclusion, antibodies to Akabane virus were detected in 7.55% cattle and pose arisk to cattle in Turkey. It will be good to know overall seroprevalence in all regions in Turkeyby considering vectors in order to make risk analyses. For this, ELISA is a good technique toanalyse many samples at a time and seropositives can be analysed by real time RT-PCR fordefinitive diagnosis. Also, it will be good to know the frequency of Akabane virus in vectorssuch as Culicoides. 85

The recent outbreak of malformations in ruminants in Northern Europe caused by Schmallenberg virus induced us to analyze the genetic properties of the related orthobunyaviruses and clarify their relationship. The sequencing of three genomic RNA segments of Sathuperi, Shamonda and Douglas viruses (SATV, SHAV and DOUV) revealed that the M RNA segment of SATV and DOUV had a high degree of sequence identity with that of Schmallenberg virus, but the S and L RNA segments closely matched those of SHAV. Phylogenetic analysis of the three genomic RNA segments indicated that Schmallenberg virus is a reassortant, with the M RNA segment from SATV and the S and L RNA segments from SHAV.

Akabane disease characterized mainly by fetal damage is a ruminant disease caused by insect-transmitted Akabane virus infection.We investigated Akabane disease using serum neutralization tests in 446 blood samples collected from 187 cattle and 259 sheep of Xinjiang province, northwest China.(1) The overall prevalence rate of neutralizing antibody was 19.06 % (85/446), (2) the prevalence rates of Akabane disease in cattle and sheep were 20.32 % (38/187) and 18.15 % (47/259), respectively, (3) the disease prevalence rates were not significantly different between cattle and sheep, but significantly different among samples collected from different sampling months, (4) the disease was most prevalent in July when mosquitoes and culicoides were most active, and (5) the disease prevalence rates were significantly different between individuals with abortion experience and without abortion experience (P0.05), suggesting that Akabane virus infection may significantly increase abortion risk in cattle and sheep.To our knowledge, this is the first report confirming that Akabane virus infection is common in cattle and sheep of Xinjiang province, northwest China and providing useful epidemiological information for cattle and sheep abortion prevention and control.

Seroprevalence was highest in the eastern part of the country, bordering Germany, where the virus was first identified., Infections with Schmallenberg virus (SBV) are associated with congenital malformations in ruminants. Because reporting of suspected cases only could underestimate the true rate of infection, we conducted a seroprevalence study in the Netherlands to detect past exposure to SBV among dairy cattle. A total of 1,123 serum samples collected from cattle during November 2011–January 2012 were tested for antibodies against SBV by using a virus neutralization test; seroprevalence was 72.5%. Seroprevalence was significantly higher in the central-eastern part of the Netherlands than in the northern and southern regions (p

In 2011, an unidentified disease in cattle was reported in Germany and the Netherlands. Clinical signs included fever, decreased milk production, and diarrhea. Metagenomic analysis identified a novel orthobunyavirus, which subsequently was isolated from blood of affected animals. Surveillance was initiated to test malformed newborn animals in the affected region.

Epizootic outbreaks of congenital malformations in sheep are rare and have, to the best of our knowledge, never been reported before in Europe. This paper describes relevant preliminary findings from the first epizootic outbreak of ovine congenital malformations in the Netherlands. Between 25 November and 20 December 2011, congenital malformations in newborn lambs on sheep farms throughout the country were reported to the Animal Health Service in Deventer. Subsequently, small ruminant veterinary specialists visited these farms and collected relevant information from farmers by means of questionnaires. The deformities varied from mild to severe, and ewes were reported to have given birth to both normal and deformed lambs; both male and female lambs were affected. Most of the affected lambs were delivered at term. Besides malformed and normal lambs, dummy lambs, unable to suckle, were born also on these farms. None of the ewes had shown clinical signs during gestation or at parturition. Dystocia was common, because of the lambs' deformities. Lambs were submitted for post-mortem examination, and samples of brain tissue were collected for virus detection. The main macroscopic findings included arthrogryposis, torticollis, scoliosis and kyphosis, brachygnathia inferior, and mild-to-marked hypoplasia of the cerebrum, cerebellum and spinal cord. Preliminary data from the first ten affected farms suggest that nutritional deficiencies, intoxication, and genetic factors are not likely to have caused the malformations. Preliminary diagnostic analyses of precolostral serum samples excluded border disease virus, bovine viral diarrhoea virus, and bluetongue virus. In December 2011, samples of brain tissue from 54 lambs were sent to the Central Veterinary Institute of Wageningen University Research, Lelystad. Real-time PCR detected the presence of a virus, provisionally named the Schmallenberg virus, in brain tissue from 22 of the 54 lambs, which originated from seven of eight farms that had submitted lambs for post-mortem examination. This Schmallenberg virus was first reported in Germany and seems to be related to the Shamonda, Aino, and Akabane viruses, all of which belong to the Simbu serogroup of the genus Orthobunyavirus of the family Bunyaviridae. These preliminary findings suggest that the Schmallenberg virus is the most likely cause of this epizootic of ovine congenital malformations, which is the first such outbreak reported in Europe

International audience; AbstractSchmallenberg virus (SBV) is an Orthobunyavirus that induces abortion, stillbirths and congenital malformations in ruminants. SBV infection induces a long lasting seroconversion under natural conditions. The persistence of the protective immunity and the isotype specific antibody response upon SBV infection of sheep has however not been studied in detail. Five sheep were kept in BSL3 facilities for more than 16 months and subjected to repeated SBV infections. Blood was regularly sampled and organs were collected at euthanasia. The presence of SBV RNA in serum and organs was measured with quantitative real-time PCR. The appearance and persistence of neutralizing and SBV nucleoprotein (N) isotype specific antibodies was determined with virus neutralization tests (VNT) and ELISAs. The primo SBV infection protected ewes against clinical signs, viraemia and virus replication in organs upon challenge infections more than 15 months later. Production of neutralizing SBV specific antibodies was first detected around 6 days post primo-inoculation with VNT and correlated with the appearance of SBV-N specific IgM antibodies. These IgM antibodies remained present for 2 weeks. SBV-N specific IgG antibodies were first detected between 10 and 21 dpi and reached a plateau at 28 dpi. This plateau remained consistently high and no significant decrease in titre was found over a period of more than 1 year. Similar results were found for the neutralising antibody response. In conclusion, the SBV specific IgM response probably eliminates SBV from the blood and the protective immunity induced by SBV infection protects sheep against reinfection for at least 16 months.

Most viral infections that affect the central nervous system of ruminants are exotic to Australia. As such, this review focuses on viruses of importance in Australian ruminants, including Akabane virus and the ruminant pestiviruses, bovine viral diarrhoea virus and border disease virus, as well as bluetongue virus. Each virus is discussed in terms of pathogenesis, clinical signs and diagnosis.

To investigate the Schmallenberg virus (SBV) in Turkey, 116 aborted fetuses from sheep (60), goats (12), and cattle (44) collected from different regions of Turkey were analyzed by real-time PCR. SBV RNA was detected in aborted fetuses of sheep and cattle from the Marmara region, which borders the European Union. In contrast, samples were found to be negative for Akabane virus by real-time PCR. The partial sequencing of the S gene of SBV confirmed the first detection of SBV in Turkey.

To the Editor: The teratogenic Schmallenberg virus (SBV) (genus Orthobunyavirus) was detected in bovine semen in a recent German field study (1). Vector-borne transmission by Culicoides spp. biting midges is most common (2), but venereal transmission of SBV might contribute to the spread of this virus to previously unaffected regions. We investigated the infectivity of SBV RNA–positive semen by experimental subcutaneous injection of cattle and interferon α/β receptor–deficient (IFNAR−/−) mice (3). Commercially produced semen straws with egg yolk–based diluent were used for the injection of 6- to 9-month-old heifers. The straws originated from 6 semen batches (quantification cycle [Cq] values 26.4–36.4) collected from 6 bulls (designated A–C and E–G) during August and September 2012 (1). To increase the probability of SBV infection of injected cattle, 5 straws of semen (≈220 µL each) from 1 batch from an individual bull were pooled and diluted in minimal essential medium with antibiotics to 4 mL. Six cattle (C1–6) were subcutaneously inoculated, each with a pool from 1 of the 6 bulls. To investigate the infectivity of a single insemination dose (1 straw), 5 cattle (C7–C11) were subcutaneously injected with single straws from bull F that had been confirmed to contain infectious SBV. Serum samples were obtained on several days (Figure), and clinical signs and rectal body temperatures for the injected cattle were monitored daily. Figure Detection of Schmallenberg virus (SBV) RNA and antibodies in serum of 5 of 11 cattle (C) injected with SBV RNA–positive bovine semen (quantification cycle [Cq] values 26.4–36.4). Infectivity was measured by using reverse transcription ... In addition, 20 SBV RNA–positive semen batches (Cq 25.9 to 36.5) collected from 11 bulls (A–K) during August–November 2012 (1) were subcutaneously injected into 40 IFNAR−/− mice (4–6 weeks old). For each batch, 2 mice were each injected with half of a semen straw (80–120 µL). All mice were monitored clinically and weighed daily. Samples of serum, liver, and spleen were harvested immediately after euthanasia at 22 days postinjection (dpi). All serum samples and organ homogenates were tested for SBV RNA by using small segment–specific quantitative reverse transcription PCR (4). Serum samples were tested for SBV-specific antibodies by using the ID Screen Schmallenberg Virus Competition ELISA (IDvet, Montpellier, France), according to the manufacturer’s instructions; selected serum samples were also tested by neutralization test against an original SBV isolate from Germany, as described (5). SBV infection was confirmed in 5 of 11 injected cattle: C3, C5, and C9–C11. SBV RNA (Cq 25.0–29.3) was first detected in serum at 3 to 6 dpi and persisted for 2–4 days. Seroconversion occurred at 8–12 dpi (Figure). None of the SBV-infected animals showed obvious clinical signs or fever; this finding is in accordance with reports of subclinical SBV infection in adult cattle (5–7). Samples from the other 6 cattle and all IFNAR−/− mice had negative results (data not shown). The 2 infectious semen batches contained moderate (Cq 26.4) or low (Cq 34.2) viral loads of SBV RNA, indicating that a high sensitivity is required for reliable SBV RNA detection in semen samples (1). The onset of SBV infection in the 3 animals injected with single semen straws ranged from 3 to 5 dpi, and not every straw was infectious, although biologic and technical replicates of straws from 1 semen batch showed similar PCR results (data not shown) (1). Possible explanations for differences in the infectivity of individual straws are that the viral RNA load of an SBV-containing straw does not necessarily correlate with infectivity or that the infectivity of 1 straw is lower than the minimal cattle infectious dose for SBV. Cattle might be more susceptible than IFNAR−/− mice to infection, particularly when SBV titers are low or borderline (7, 8). Therefore, we cannot exclude the possibility that the semen batches tested only in IFNAR−/− mice might be infectious for cattle or that semen samples with higher SBV titers might be infectious in the mice. We used subcutaneous injection of SBV RNA–positive semen to demonstrate infectivity because this transmission route has a high sensitivity for proving infectivity of SBV-containing samples (7). However, the possibility of intrauterine SBV infection of dams is unknown. Oro-nasal inoculation of 2 calves did not result in SBV infection of the animals (5), which suggests that mucosal in utero infection with SBV-containing semen is unlikely. In contrast, viremia was detected in most cows that were artificially inseminated and simultaneously inoculated in the uterus with cell culture–passaged Akabane virus, a teratogenic orthobunyavirus closely related to SBV (9). Intrauterine lesions caused by insemination or breeding might therefore increase the risk for SBV infection. In conclusion, we demonstrated that SBV RNA–positive bovine semen could contain infectious SBV. However, the actual risk for transmission of SBV by insemination of dams with SBV-containing semen remains to be evaluated. Although SBV infection of the developing embryo is unlikely, venereal transmission would lead at worst to viremia of the dam, facilitating vector transmission. To prevent venereal SBV transmission, sensitive PCR testing of semen batches from SBV-infected bulls is the method of choice (1,10).

Bayesian Inference (BI) and Neighbor Joining (NJ) analyses of the phylogenetic relationships between the nucleotide sequences of the N gene of Akabane virus revealed an unclear topology among genogroups I-III, which was probably caused by genetic reassortment or recombination between these genogroups. In contrast, nucleotide and amino acid phylogenetic tree analyses of the M RNA segment agreed with the topologies obtained by using the BI and NJ methods. Therefore, distinct genogrouping of Akabane virus isolates should be performed using the M RNA segment. Four Korea isolates were classified into genogroup II together with Akabane virus strains isolated from all areas of Japan, including Okinawa Island. However, more nationwide isolates and more clinical data from Korean cattle farms will be required in the future to confirm the precise relationships between genotypes and pathogenicity.

Akabane disease, caused by the insect-transmitted Akabane virus (AKAV), affects livestock by causing life-threatening deformities or mortality of fetuses. Therefore, Akabane disease has led to notable economic losses in numerous countries, including Japan. In this short communication, a new T7 RNA polymerase-based AKAV reverse genetics system was developed. Using this system, in which three plasmids transcribing antigenomic RNAs were transfected into cells stably expressing T7 polymerase, we successfully reconstituted the live attenuated vaccine TS-C2 strain (named rTTT), and also generated a mutant AKAV (rTTTΔNSs) that lacked the gene encoding the nonstructural NSs protein, which is regarded as a virulence factor. Analysis of growth kinetics revealed that rTTTΔNSs grew at a much slower rate than the rTTT and TS-C2 virus. These results suggest that our established reverse genetics system is a powerful tool that can be used for AKAV vaccine studies with gene-manipulated viruses.

Diagnosing the cause of bovine congenital malformations (BCMs) is challenging for bovine veterinary practitioners and laboratory diagnosticians as many known as well as a large number of not-yet reported syndromes exist. Foetal infection with certain viruses, including bovine virus diarrhea virus (BVDV), Schmallenberg virus (SBV), blue tongue virus (BTV), Akabane virus (AKAV), or Aino virus (AV), is associated with a range of congenital malformations. It is tempting for veterinary practitioners to diagnose such infections based only on the morphology of the defective offspring. However, diagnosing a virus as a cause of BCMs usually requires laboratory examination and even in such cases, interpretation of findings may be challenging due to lack of experience regarding genetic defects causing similar lesions, even in cases where virus or congenital antibodies are present. Intrauterine infection of the foetus during the susceptible periods of development, i.e. around gestation days 60–180, by BVDV, SBV, BTV, AKAV and AV may cause malformations in the central nervous system, especially in the brain. Brain lesions typically consist of hydranencephaly, porencephaly, hydrocephalus and cerebellar hypoplasia, which in case of SBV, AKAV and AV infections may be associated by malformation of the axial and appendicular skeleton, e.g. arthrogryposis multiplex congenita. Doming of the calvarium is present in some, but not all, cases. None of these lesions are pathognomonic so diagnosing a viral cause based on gross lesions is uncertain. Several genetic defects share morphology with virus induced congenital malformations, so expert advice should be sought when BCMs are encountered. Electronic supplementary material The online version of this article (doi:10.1186/s13028-015-0145-8) contains supplementary material, which is available to authorized users.

The OBE-1 strain of Akabane virus infects the fetus via the dam, resulting in abortion or congenital abnormalities in ruminants. In contrast, the Iriki strain of Akabane virus is highly virulent and causes encephalomyelitis by post-natal infection. To clarify the difference in pathogenicity between the two strains, BALB/cAJcl mice were inoculated either intraperitoneally or intracerebrally (IC) with either strain from 3 days to 8 weeks of age. Pathological examination revealed non-suppurative encephalitis in mice inoculated by either route with the Iriki strain. Virus antigens were distributed widely throughout the brain when the virus was inoculated into newborn mice, but distribution was limited to the brainstem in mice inoculated when 8 weeks old. However, brain lesions were observed only in mice inoculated with OBE-1 by the IC route when the mice were 3 days old, but these lesions were mild. To examine the manner of viral spreading, the Iriki strain was inoculated IC or intrastriatally into 8-week-old mice. Viral antigens were distributed prominently throughout the spinal cord as well as the brainstem and various cerebral nuclei, and were present with less prominence in the connective fibres. Virus antigens were also distributed in the subventricular zone, where neuronal stem cells exist. These results show that the neuroinvasiveness of the Iriki strain diminishes with age, while neurovirulence is maintained; however, for the OBE-1 strain both neuroinvasiveness and neurovirulence diminish with age. Furthermore, Akabane virus infects neuronal cells in the brainstem and spreads to the spinal cord via an unidentified transneuronal pathway.

Schmallenberg virus (SBV) emerged across Europe in 2011 and Belgium was among the first countries affected. In this study, published findings are combined with new data from veterinary surveillance networks and the Belgian reference laboratory for SBV at the Veterinary and Agrochemical Research centre (CODA-CERVA) to reconstruct the epidemic in Belgium. First retrospective cases of SBV were reported by veterinarians that observed decreased milk yield and fever in dairy cattle in May 2011. The number of SBV suspicions subsequently increased in adult cattle in August 2011. That month, first SBV positive pools of Culicoides were detected and extensive virus circulation occurred in Belgium during late summer and autumn 2011. As a consequence, most pregnant ruminants were infected and their fetuses exposed to the virus. This resulted in an outbreak of abortions, still-births and malformed new-borns observed between January and April 2012. The number of cases drastically diminished in 2012-2013, although multiple lines of evidence obtained from cross-sectional serological surveys, analyses on aborted foetuses, sentinel herd surveillance and surveillance of SBV in vectors prove that SBV was still circulating in Belgium at that time. Virus circulation was then probably strongly reduced in 2013-2014, while increasing evidence indicates its recirculation in 2014-2015 in Belgium. Based on the experience gathered with the closely related Akabane virus, recurrent outbreaks of congenital events can be expected for a long period. Vaccination of seronegative animals before the first mating could be used to prevent the deleterious effects of SBV. During this epidemic, different surveillance approaches including syndromic surveillance, sentinel herd surveillance, cross-sectional seroprevalence studies and pathogen surveillance in vectors have proven their utility and should be considered to continue in the future.

Background: Schmallenberg virus (SBV), Akabane virus (AKAV) and Aino virus (AINV) are members of the Simbu serogroup within the genus Orthobunyavirus, family Bunyaviridae, which can cause reproductive disorders including abortion, stillbirth and congenital malformation in ruminants. Because, the clinical signs are similar, confirmatory diagnosis requires viral detection to differentiate infection between these three viruses. Methods: In this study, a one-step multiplex reverse-transcriptase quantitative PCR (one-step mRT-qPCR) was developed for the simultaneous detection and differentiation of SBV, AKAV and AINV. Results: The detection limit of the one-step mRT-qPCR for SBV, AKAV and AINV were 2.4 copies (10(0.6) TCID (50)/ml), 96.2 copies (10(1.5) TCID (50)/ml) and 52.3 copies (10(1.2) TCID (50)/ml), respectively. Various field samples such as bovine serum, bovine whole blood, bovine brain, goat serum and Culicoides were analyzed using the one-step mRT-qPCR and compared with previously published RT-qPCRs. The test results of the field samples were identical for the one-step mRT-qPCR and RT-qPCRs, which showed all samples to be negative for SBV, AKAV and AINV, except for one bovine brain sample (1/123) that was positive for AKAV. Conclusion: The one-step mRT-qPCR allows for the simultaneous detection of three viral pathogens (SBV, AKAV and AINV) that cause reproductive failure.

Characterization of the small RNA segment of the teratogenic Akabane virus was performed to define the genetic heterogeneity and molecular epidemiology of the virus. The nucleotide and amino acid sequences were highly conserved among the Akabane virus isolates, irrespective of the year of isolation and geographical origin, except for a Kenyan strain MP496. On the basis of the nucleocapsid gene sequences of the segment, 170 field isolates were grouped into four distinct phylogenetic lineages. The Japanese isolates were divided into two major clusters, one containing the prototype strain JaGAr39 and strains isolated in the 1970s, 1988-1989, 1991, and 1994-1999, and the other containing strains isolated from 1982 to 1987, 1990, 1993, 1998, and 2000 to 2003 together with the Taiwanese and Israeli strains. The Asian strains seemed to have evolved in a common gene pool. The Australian and Kenyan strains were placed in the independent third and fourth clusters of the phylogenetic tree, respectively. No consecutive mutations have occurred on the small RNA segment of the Japanese isolates, indicating that the various genotypes of the virus might invade continuously from an exotic source and that certain viruses adaptable to the Japanese environment might spread transiently.

In response to recent increases in cases of pediatric encephalitis with unknown etiology in northern Vietnam, surveillance for arbovirus activity was conducted in four provinces surrounding the city of Hanoi during June 2002 and July-August 2004. A total of 20,615 mosquitoes consisting of 19 species in 1,122 pools were processed for virus isolation; virus isolates were obtained from 44 pools. Sagiyama virus (11 isolates), Getah virus (15 isolates), Oya virus (13 isolates), and Akabane virus (4 isolates) were identified by immunofluorescence assay and sequence analysis of reverse transcription-polymerase chain reaction fragments. Surprisingly, no isolates of Japanese encephalitis (JE) virus were obtained. Isolation of Akabane virus, Oya virus, Getah virus, and Sagiyama virus is reported for the first time from Vietnam.

Single-tube multiplex reverse transcription-polymerase chain reaction (mRT-PCR) assay was developed to detect and identify arboviruses in infected cell-culture fluids and field specimens. The technique was equally sensitive for detecting five different viruses in cell cultures, namely the Chuzan, Ibaraki, and Bluetongue viruses belonging to Orbivirus, and the Akabane virus and Peaton virus belonging to Orthobunyavirus, and was less sensitive than former viruses for detecting Aino virus belonging to Orthobunyavirus. The mRT-PCR reliably detected 0.6-10(3.1) median tissue culture infective doses. The mRT-PCR readily identified viruses by discriminating the size of their amplified gene products. The technique was as sensitive as virus isolation in detecting single infected plasma in five plasmas from sentinel cattle and in detecting two infectious homogenates in eight homogenates of Culicoides biting midges. The mRT-PCR may be a sensitive and rapid assay for surveillance of bovine arboviruses in field specimens.

Akabane (AKA) virus is considered a pathogen of herbivores in nature. However, we found that pig populations in fields were infected in Taiwan. An isolate (NT-14) of AKA virus was obtained from pigs. The NT-14 virus was able to infect pigs by the oronasal route. Subsequently, low levels of infectious virus particles were excreted into the oronasal discharge during the stage of viremia but they were not sufficient to infect new porcine hosts via contact transmission. The prevalence of serum neutralizing antibodies to AKA virus in pig populations was investigated, indicating that approximately 75% of pigs in Taiwan were seropositive. Sows and newborn piglets have the highest titers of neutralizing antibodies. Contrarily, fattening pigs aged at approximately 20 weeks old contained the lowest titers of specific antibodies. Our results suggest that pigs in natural situations are part of the AKA virus transmission cycle.

A novel virus, Schmallenberg virus (SBV), was discovered in Europe in October 2011, and since then, cases of SBV infection have been reported in sheep, cattle, and goats in several European countries (1–4). Preliminary phylogenetic analyses revealed that SBV is a member of the genus Orthobunyavirus within the family Bunyaviridae and is related to Simbu serogroup viruses (1). Similar to Akabane virus (AKAV), another Simbu serogroup virus, SBV can cause fatal congenital defects by infection of fetuses during a susceptible stage in pregnancy (2). Vaccines for SBV are not available. Thus, SBV poses a serious threat to naive populations of ruminant livestock in Europe. Orthobunyaviruses are arthropod-borne viruses with a negative-stranded tripartite RNA genome comprising large (L), medium (M), and small (S) segments. Genetic reassortment occurs naturally among these viruses, which results in the emergence of new virus strains that have altered biologic properties (5). The L segment encodes the RNA-dependent RNA polymerase; antigenic determinants are the M-encoded viral surface glycoproteins Gn and Gc, which are responsible for viral attachment, cell fusion, hemagglutination, and the induction of neutralizing antibodies, and the S-encoded nucleocapsid protein N, which plays a role in complement fixation (6). In the pregenomics era, orthobunyavirus relationships were determined solely by serologic cross-reactivity analyses (7), but since DNA sequencing became available, phylogenetic relationships have additionally been assessed by comparison of partial genome sequences (8,9). However, published full-length genome sequence information is sparse, which makes in-depth phylogenetic analysis difficult. Therefore, a detailed taxonomic classification of SBV could not be made initially when the virus emerged. The first report of SBV showed highest similarities of M- and L-segment sequences to partial Aino virus and AKAV sequences, whereas the N gene was most closely related to Shamonda virus (SHAV) (1). Additionally, results of recent investigations on complete N and M genes and partial L genes of SHAV, Douglas virus (DOUV), and Sathuperi virus (SATV) suggested that SBV is a reassortant consisting of the M segment from SATV and the S and L segments from SHAV (9). Conversely, in 2001, SHAV was described as a reassortant virus comprising the S and L segments of SATV and the M segment from the unclassified Yaba-7 virus (8). To clarify the phylogenetic relationships and classification of SBV within the Simbu serogroup, we conducted genetic and serologic investigations of its relationship to 9 other Simbu serogroup viruses.

To the Editor: Viruses in the Simbu serogroup are arboviruses that cause abortion, stillbirth, and congenital abnormalities in domestic ruminants. Akabane virus (AKAV), Aino virus (AINV), and Schmallenberg virus are the most studied in this serogroup; Shuni, Sabo, Shamonda, and Sango viruses (1,2) are examined less frequently. Until 2012, only AKAV had been associated with congenital abnormalities in Israel, although AINV had been identified serologically in dairy cow herds with no clinical signs in 2003 (3). Moreover, of 15 brain samples collected during February–October 2012 from adult cows with central nervous system manifestations, 6 were positive for AKAV by PCR. In late December 2014, the Israeli Veterinary Field Services was notified of the appearance of arthrogryposis-hydranencephaly syndrome (1) in 2 herds of sheep in the villages of Yokneam and Sde Ya’akov, respectively; both villages are located in the Izre’el Valley, in Israel’s northern valleys (Technical Appendix Figure 1), where several arboviral infections have occurred in recent decades. From our past experience (3), ≥1 virus of the Simbu serogroup was suspected to have infected the ruminants, probably during August–October 2014. We collected 27 samples of brain, placenta, spleen, lung, and blood (mixed with EDTA to prevent coagulation) from 15 sheep, goats, and cattle. Most samples were from the 2 affected flocks in the northern valley; a few were from ruminants in additional locations: Avadon, near Israel’s border with Lebanon; Ein Hachoresh, near central Israel; and Hura, close to the Negev desert (Technical Appendix Figure 1). Of the 27 samples, 23 (85%) were positive for Shuni virus (SHUV) by PCR (Table). SHUV, which had not been reported in Israel, was isolated from the brain and placenta of 1 malformed lamb (strain 2504/3/14; sample 11 in the Table). Moreover, partial nucleotide sequences of the small, medium, and large DNA segments (580/850, 4,320/4,326, and 285/6,880 bp, respectively) were identified from 3 samples (strains Yokneam 2417/2/14 and 2504/3/14 and Hura 273/14 from samples 2, 11, and 9, respectively, in the Table; Technical Appendix Figure 2). Sequence data obtained by conventional PCR in this study have been deposited into GenBank (accession nos. {"type":"entrez-nucleotide","attrs":{"text":"KP900863","term_id":"940795874","term_text":"KP900863"}}KP900863–5, {"type":"entrez-nucleotide","attrs":{"text":"KP900873","term_id":"940795878","term_text":"KP900873"}}KP900873–5, {"type":"entrez-nucleotide","attrs":{"text":"KP900879","term_id":"940795892","term_text":"KP900879"}}KP900879–80, and {"type":"entrez-nucleotide","attrs":{"text":"KP900884","term_id":"940795926","term_text":"KP900884"}}KP900884). Phylogenetic analysis of the samples showed that they were isolates of SHUV (Technical Appendix Figure 2). Additional SHUV RNA-specific fragments were detected in pathologic samples from kids, lambs, and calves (Table). Full-genome sequences were not performed, although sequencing should be done when possible to determine precise origin of isolates. Table Summary of diagnostic and laboratory findings, animal species, sample materials, and region where samples were collected in the study of Shuni virus infection in ruminants, Israel, 2014–15* For further testing, we inoculated homogenate material from 7 distinct malformations (samples 1, 2, 6, 8, 11, 12, and 15 in the Table) into baby mice; only 1 family of baby mice inoculated intracerebrally with the SHUV isolate (sample 11 in the Table) exhibited characteristic neurologic signs of nervousness. PCR confirmed that SHUV caused the cerebral infections in these mice. The isolate was also suitable for further propagation in the Vero cell line (Table). Our results showed the presence of SHUV in sheep in Israel during the winter of 2014–15 and suggest a northward expansion of SHUV from sub-Saharan Africa. Although SHUV was first isolated in the 1960s (2), its role as a pathogen has been shown only recently in its involvement in encephalitis in horses (4). We isolated SHUV from the pathologic fetal brain of a malformed lamb, an unusual laboratory finding because, although Simbu viruses are readily isolable from vectors or exposed animals during the 3 or 4 days of viremia, they are seldom isolable from pathologic specimens collected for study of congenital malformations. We deduce from the clinical evidence that malformations appear up to 6 months after infection with SHUV and after the virus has been eliminated from the host after immune activity. Thus, isolation of SHUV from malformed brains may indicate strong neurotropism of this putative pathogen. The possibility of its replication in the fetal nervous system should also be considered because an affected fetus that is born alive is likely a reservoir. Indeed, AKAV was identified in the hippocampus (only) of adult lactating cows (data not shown), and similar epidemiologic evidence might result from other Simbu virus infections. A serologic survey conducted in Israel during the 2001–2003 outbreaks of AHS showed reactivity of AINV to serum samples of ruminants in Israel’s southern regions (3). Because AINV and SHUV are known to have a strong serologic cross-reaction, SHUV has likely previously infiltrated Israel. However, whether the seroreactivity results from AINV or SHUV remains unresolved. The emergence and reemergence of arboviruses should interest medical practitioners, particularly epidemiologists. The appearance of exotic viruses in unexpected locations might result in more severe pathology in newly invaded regions than in the original arbovirus-endemic areas. Furthermore, SHUV has been detected in a child with febrile illness (2), a finding that suggests a potential zoonotic problem. Technical Appendix. Map showing locations where Shuni viruses were detected in ruminants in Israel, 2014–15, and phylogenetic trees of Simbu serogroup viruses. Click here to view.(333K, pdf)

To investigate the possible circulation of arboviruses in South Korea, nationwide surveillance of five arbovirues was conducted in sentinel calves during 2009−2012. We used serum neutralization tests to investigate the presence of antibodies for the Aino virus, Akabane virus, bovine ephemeral fever virus, Chuzan virus and Ibaraki virus. In 2009, 2011 and 2012, the seropositive rates for these five arboviruses were all less than 14.1%. In 2010, however, the seropositive rates for Aino virus and Akabane virus were 33.2% and 40.2%, respectively. High seropositive rates were also associated with a large-scale outbreak of Akabane viral encephalomyelitis in cattle in southern Korea in 2010. Continued seroprevalence surveillance will be useful for monitoring natural arboviral diseases.

In 2011, Schmallenberg virus (SBV), a novel member of the Simbu serogroup, genus Orthobunyavirus, was identified as the causative agent of a disease in ruminants in Europe. Based on the current knowledge on arthropods involved in the transmission of Simbu group viruses, a role of both midges and mosquitoes in the SBV transmission cycle cannot be excluded beforehand. The persistence of SBV in mosquitoes overwintering at SBV-affected farms in the Netherlands was investigated. No evidence for the presence of SBV in 868 hibernating mosquitoes (Culex, Anopheles, and Culiseta spp., collected from January to March 2012) was found. This suggests that mosquitoes do not play an important role, if any, in the persistence of SBV during the winter months in northwestern Europe.

During the Schmallenberg virus (SBV) epidemic, the European Food Safety Authority (EFSA) collected data on SBV occurrence across Europe in order to provide an assessment of spread and impact. By May 2013, twenty-nine countries were reporting to EFSA and twenty-two countries had reported cases of SBV. The total number of SBV herds reported was 13,846 and the number of SBV laboratory confirmed herds was 8730. The surveillance activities were based on the detection of SBV clinical cases (either adults or newborns). Malformation in newborns was the most commonly reported clinical sign of SBV-infection. All countries were able to provide the date when the first suspicion of SBV in the herd was reported and nineteen could report the location of the herd at a regional level. This allowed the spread of SBV in Europe to be measured both temporally and spatially. The number of SBV confirmed herds started to increase in December 2011 and two peaks were observed in 2012 (February and May). Confirmed herds continued to be reported in 2012 and into 2013. An increase during winter 2012 and spring 2013 was again observed, but the number of confirmed herds was lower than in the previous year. SBV spread rapidly throughout Europe from the initial area of detection. SBV was detected above the latitude of 60° North, which exceeds the northern expansion observed during the bluetongue virus serotype 8 epidemic in 2006-2009. The impact of SBV was calculated as ratio of the number of herds with at least one malformed SBV positive foetus and the total number of herds in this region. The 75th percentile of the malformations ratio in the various affected countries for the whole reporting period was below 1% and 3% for cattle and sheep herds, respectively. International data collection on emerging diseases represents a challenge as the nature of available data, data quality and the proportion of reported cases may vary widely between affected countries. Surveillance activities on emerging animal diseases are often structured only for case detection making the estimation of infection/diseases prevalence and the investigation of risk factors difficult. The impact of the disease must be determined to allow risk managers to take appropriate decisions. Simple within-herd impact indicators suitable for emerging disease outbreaks should be defined that could be measured as part of routine animal health surveillance programmes and allow for rapid and reliable impact assessment of emerging animal health diseases.