Epidemiology and control of bovine ephemeral fever

A Bayesian latent class estimation of the diagnostic accuracy of clinical examination and laboratory assays to identify bovine ephemeral fever virus infection in South African cattle

Bovine ephemeral fever (BEF) is an economically important vector-borne viral disease of cattle and water buffalo in Africa, Australia and parts of Asia. The control of BEF is centred around vaccination, and therefore accurate, early identification of disease outbreaks are key to minimize its economic and welfare impact. In Africa, control programs are hampered by limited diagnostic capabilities and poor infrastructure for rapid transportation of diagnostic specimens. The primary objective of this study was to estimate the sensitivity (Se) and specificity (Sp) of four tests, namely clinical examination by a veterinarian, virus isolation and two different conventional PCR assays, to identify an acute bovine ephemeral fever virus (BEFV) infection in diseased, naturally infected South African cattle, without the assumption of a reference standard. Samples and data were collected from cattle with clinical signs suggestive of BEF rather than a random sample of cattle. A case was categorised as clinical examination positive if the examining veterinarian considered acute BEFV-infection as the most likely aetiology. Virus isolation was performed using the buffy coat of heparin blood samples on baby hamster kidney cell cultures, evaluating cytopathic effect and confirming virus morphology by transmission electron microscopy. PCR was performed using two previously published protocols: The Ephemerovirus L-gene PCR (targeting the RNA-dependent RNA polymerase gene) and a BEFV G-gene PCR (targeting the neutralising G1 epitope of the glycoprotein). A single population, four test Bayesian latent class model with conditional dependence between the two PCR assays was implemented. The prevalence of BEFV-infection was high in this study population of clinical suspects at 67 %, (95 % Probability Interval (PI) 52 %; 81 %). Clinical examination provided a reasonable indication of acute BEFV infection (Se of 86 % (PI 77 %; 93 %) and Sp of 67 % (PI 52 %; 82 %)). Virus isolation was the most specific (99 % (PI 97 %; 100 %)), but least sensitive assay (30 % (PI 20 %; 44 %)). Of the two conventional PCRs, the L-gene PCR outperformed the G-gene PCR: The L-gene Se was 64 % (PI 51 %; 76 %) and Sp 96 % (PI 84 %; 100 %) compared to Se of 50 % (PI 38 %; 61 %) and Sp of 89 % (PI 75 %; 98 %) for the G-gene. While the laboratory assays presented excellent positive predictive values within this high disease prevalence population, the poor negative predictive values limit their usefulness to field veterinarians attempting to exclude BEF as diagnosis. Novel pen-side diagnostics should be developed due to the limitations of currently available assays and infrastructure constraints prevalent in Africa.

VAPA suppresses BEFV and VSV-induced type I IFNs signaling response by targeting JAK1 for NEDD4-mediated ubiquitin-proteasome degradation

VAMP-associated protein A (VAPA) binds to various proteins involved in multiple cellular processes, however, its role in the regulation of type I interferons (IFN-I) signaling has not been elucidated. In this study, we demonstrate that VAPA negatively regulates the IFN-I signaling during bovine epidemic fever virus (BEFV) and vesicular stomatitis virus (VSV) infection. Upon treatment with IFN-β, VAPA negatively regulates the JAK-STAT signaling pathway. Further studies show that VAPA inhibits the IFN-I signaling by promoting the degradation of JAK1 through the ubiquitin-proteasome system during BEFV and VSV infection. Mechanistically, VAPA facilitates the interaction between the E3 ubiquitin ligase NEDD4 and JAK1, thereby enhancing the ubiquitination and subsequent degradation of JAK1. Furthermore, viral titers are markedly reduced, and the promoting effect of VAPA on VSV or BEFV replication is attenuated in NEDD4-deficient cells. Taken together, our findings reveal a novel role for VAPA in negatively regulating the IFN-I signaling response and provide a molecular basis for the design of targeted antiviral agents.

A Novel Ephemero- and a New CHeRI Orbivirus Isolated from a Dead Farmed White-Tailed Deer (Odocoileus virginianus) in Florida, USA

A novel ephemeral fever rhabdovirus and a CHeRI orbivirus of a previously unidentified genetic lineage were isolated in mosquito cell line C6/36 cells as co-infecting agents from the spleen tissue of a dead farmed white-tailed deer (WTD; Odocoileus virginianus) in Florida. We designated the ephemeral fever rhabdovirus as Hardee County ephemerovirus 1, strain CHeRI ephemerovirus 1. The genetic sequences of the CHeRI orbivirus isolated in this work differ significantly from those of three previously described CHeRI orbivirus lineages. We designated this new virus as CHeRI orbivirus 4, strain CHeRI orbivirus 4-1. Whereas it remains unknown whether one, both, or none of the viruses contributed to the pathology, gross observations revealed that the dead WTD had severely congested and hemorrhagic lungs, and that its heart, kidneys, and spleen were also congested.

Identification and genetic analysis of new ephemeroviruses in wild boars in China

Ephemeroviruses (EVs) are arthropod-borne rhabdoviruses and were isolated exclusively from cattle and haematophagous arthropods until two new ephemeroviruses were first identified from domestic pigs most recently. Here we report the identification of newer EVs in wild boar by meta-transcriptomic (MTT) sequencing. Further screening by specific RT-nPCR of tissue samples of 459 free-ranging wild boars collected between 2018 and 2023 from 26 provinces across China confirmed five positive wild boars in four provinces. Interestingly, two ticks especially collected from two positive wild boars were also EV positive. Finally, four complete genome sequences of wild boar ephemeroviruses (WbEVs) were obtained with two strains belonging to a new EV species, and the rest two falling into porcine ephemerovirus 2 (PoEV2) species identified from domestic pigs. Our study has further extended EV host range and demonstrated natural circulations of divergent EVs in wild boars, in which ticks may play roles. Biological implications of EV infection in wild boars should be interesting topics for future investigations.

Development of New Probe-Based Real-Time RT-qPCR Assays for the Detection of All Known Strains of Bovine Ephemeral Fever Viruses

Bovine ephemeral fever is an arthropod-borne viral disease that affects cattle and buffalo in many regions of the world; it causes heavy economic losses in the cattle industry. To date, all BEFV-specific diagnostic molecular assays have been based on the variable glycoprotein (G-protein)-coding genome region, potentially allowing the pathogen to escape detection. We developed two new assays, based on the less variable nucleoprotein genome region, and compared them with two G-protein-based assays. For this comparison, we used 245 samples comprising positive and negative field samples from Israeli outbreaks caused by different strains, belonging to lineage I and IIIa, as well as Australian and Japanese strains (lineages IV and IIIb). The new assays showed high agreement with the previous assay (Kappa = 0.92), detecting 144 out of 147 positive samples (sensitivity of 97.96%), and detected 6 more samples as positive out of 98 samples found negative by the G-protein-based assay. All nine non-agreeing results were validated as positive using a conventional RT-PCR assay. The new assays have higher analytical sensitivity than the previous assays, can be combined with internal controls, and enable the detection of all known BEFVs. The results indicate that these two nucleoprotein-based real-time RT-qPCRs can serve as fast, sensitive, and specific assays for the sustainable detection of BEFV strains.

Rescue of bovine ephemeral fever virus through reverse genetics, but inability to propagate

Bovine ephemeral fever (BEF) is caused by BEF virus (BEFV) belonging to the Genus Ephemerovirus under the Family Rhabdoviridae. The BEFV carries a single-stranded, negative-sense RNA genome. Not much is known about the various aspects of BEFV replication, its interaction with cellular proteins or the cellular response to BEFV infection. Here, we report the rescue of BEFV through reverse genetics. A full-length cDNA copy of BEFV was assembled to be driven by the RNA polymerase I (PolI) promoter. Parallely, eukaryotic expression plasmids containing BEFV sequences encoding the helper proteins N, P and L, which form the replicase complex, were generated. The expression of N and P proteins were verified by using the in-house generated and purified polyclonal sera. Transfection of the full-length cDNA copy along with the helper plasmids rescued BEFV, as evaluated by transmission electron microscopy, reverse-transcription polymerase reaction, immunofluorescence and Western blotting. However, the virus did not produce a cytopathic effect and failed to be propagated beyond a certain number of passages. The results lay the foundation for establishment of reverse genetics for BEFV but also highlight the difficulties in studying this virus.

Environmental and Breed-Related Determinants of Bovine Ephemeral Fever Outbreaks in Southeastern Türkiye

BACKGROUND

Bovine ephemeral fever (BEF) is a biphasic febrile, vector-borne viral disease affecting cattle and buffaloes, leading to significant reductions in milk production and economic losses. BEF's episodic nature often leads to its classification as non-notifiable disease.

OBJECTIVES

This study aimed to investigate the environmental and breed-related determinants of BEF in Şanlıurfa, a region in southeastern Türkiye notable for its vulnerability to vector-borne diseases.

METHODS

We integrated temperature, precipitation and irrigation data with the occurrence of clinical BEF cases to identify critical environmental conditions associated with outbreaks. Additionally, we conducted an epidemiological analysis focused on a state-owned dairy farm to assess breed-specific morbidity, case fatality and mortality rates. A partial G-gene sequence from a positive sample was phylogenetically analysed to trace its origins.

RESULTS

Temperatures above 15°C, excessive rainfall and increased agricultural irrigation were identified as key factors associated with the emergence and spread of BEF. The cropping pattern, including maize and cotton cultivation, significantly influences irrigation practices and, consequently, vector population dynamics. Holstein-Friesian cattle showed higher morbidity (58.4%), case fatality (12.9%) and mortality (7.5%) rates compared to Simmental cattle, which exhibited lower rates (morbidity 28.1%, case fatality 5.2%, mortality 1.5%). Phylogenetic analysis linked the virus strain to a Middle Eastern clade from the 2018 to 2020 period.

CONCLUSIONS

The study highlights the importance of considering environmental conditions, crop patterns, and breed-specific health risks in managing BEF. Tailored intervention strategies are crucial for mitigating the economic and health impacts of BEF on dairy farms.

Potential of accelerometers to remotely early detect bovine ephemeral fever in cattle using pattern mining

Bovine Ephemeral Fever (BEF), caused by an arthropod-borne rhabdovirus, is widespread in tropical and subtropical regions. It affects cattle with symptoms of fever, lameness, inappetence and in some situations can result in mortality. The goal of this study is to determine if accelerometer data can be used to identify the behavior patterns that occur when cattle become ill from BEF. Eight heifers in a separate experiment were monitored with 3-axis accelerometers sensors. Movement variation (MV) was calculated from accelerometer data (25 Hz) using 1-min epochs and then averaged hourly. Two different approaches, cosine similarity (CS) and deviation from previous behavioral patterns, were developed to autonomously detect patterns and recognize the onset of sickness in cattle using accelerometer data. Analyses show that one heifer had behavioral changes one day before the manager observed BEF, and another heifer had behavioral changes on the same day the manager observed BEF. The other six heifers did not display any BEF symptoms. To validate the efficacy of our analytical approaches, we employed them on a separate commercial herd of 73 cows where 4 of the 27 monitored cows were observed with BEF symptoms. Predictions were either on the day or even the day prior to the manager's observation and diagnosis. There were likely no false positives in the first or second trials using the deviation algorithm with s u m _ d e v i a t i o n formula, but there were several false positives with the other algorithms. These case studies demonstrate the potential of accelerometer data to autonomously detect disease onset, in some cases before it was apparent to the human observer. However, more research is needed to minimize false positives that may occur from other similar diseases, abnormal weather events or cyclical changes in behavior such as estrus is required.

Multiplex reverse transcription recombinase polymerase amplification combined with lateral flow biosensor for simultaneous detection of three viral pathogens in cattle

Bovine viral diarrhea virus (BVDV), bovine epidemic fever virus (BEFV), and bovine respiratory syncytial virus (BRSV) cause respiratory symptoms in cattle. The absence of rapid, precise, and easily accessible diagnostic methods poses difficulties for herders and veterinary epidemiologists during outbreaks of major infectious animal diseases. Considering the mixed infection of viruses, a multiple-detection method, reverse transcription recombinase polymerase amplification (mRT-RPA) combined with a lateral flow biosensor (LFB), was established to simultaneously detect the three pathogens. This technique is based on the specific binding of three differently labeled RT-RPA products (DNA sequences) to antibodies on the three test lines of the LFB, achieving multiplex detection through the presence or absence of coloration on the LFB test lines. The fluorescence values of the LFB test lines are recorded by a test strip reader. The mRT-RPA-LFB assay completes detection at a constant temperature of 41 °C within 33 min. The limits of detection (LODs) for BVDV, BEFV and BRSV were 2.62 × 101, 2.42 × 101 and 2.56 × 101 copies/μL, respectively. No cross-reactivity was observed with the other six bovine viruses. The developed method showed satisfactory intra- and inter-assay precision, and the average coefficients of variation were ranged from 2.92 % to 3.99 %. The diagnostic sensitivity and specificity were 98.11 % and 100 %, respectively, which were highly consistent with the RT-qPCR assay, and the kappa value was 0.988 (95 % confidence interval, CI). In general, the mRT-RPA-LFB assay has the potential to become a powerful tool for rapid screening of cattle diseases because of its advantages such as fast detection speed, convenient operation, strong specificity, and high sensitivity.

Identification of a novel ephemerovirus in a water buffalo (Bubalus bubalis [Linnaeus, 1758])

Ephemeroviruses, belonging to the genus Ephemerovirus within the family Rhabdoviridae of the Mononegavirales, are non-segmented, negative-strand RNA viruses that infect artiodactyls and blood-sucking arthropods. Although recent advances in sequencing technology have facilitated the identification of novel ephemeroviruses, thereby expanding our understanding of this viral genus, their diversity remains elusive, as evidenced by phylogenetic gaps between currently known ephemeroviruses. In this study, we analyzed publicly available RNA-seq data and identified a novel ephemerovirus, tentatively named Punjab virus (PBV), in a water buffalo (Bubalus bubalis [Linnaeus, 1758]). We obtained two separate PBV contigs from the RNA-seq data; the first contig covers the N, P, and M genes, while the second contig covers the G, α, β, γ, and L genes. Together, these PBV contigs represent 99% of the estimated complete viral genome. Mapping analysis revealed a typical transcriptional gradient pattern commonly observed in mononegaviruses, suggesting that the water buffalo is the authentic host for PBV. Sequence comparisons with its closest relatives indicate that the newly identified virus meets the ICTV species demarcation criteria for sequence divergence. Thus, this study contributes to a deeper understanding of the diversity of ephemeroviruses.

The Current Epizootiological Situation of Three Major Viral Infections Affecting Cattle in Egypt

One of the major factors hindering efficient livestock production is the presence of high-impact infectious animal diseases, such as foot and mouth disease (FMD), lumpy skin disease (LSD), and bovine ephemeral fever (BEF), which are notable viral infections affecting cattle in Egypt, leading to significant economic losses. FMD is caused by the foot and mouth disease virus (FMDV) of the genus Aphthovirus in the Picornaviridae family. LSD is caused by lumpy skin disease virus (LSDV) of Capripox genus within the Poxviridae family, subfamily Chordopoxvirinae. BEF is caused by bovine ephemeral fever virus (BEFV) of genus Ephemerovirus in the Rhabdoviridae family. FMD is a highly contagious viral infection of domestic and wild cloven-hooved animals and can spread through the wind. On the other hand, LSD and BEF are arthropod-borne viral diseases that mainly affect domestic cattle and water buffalo. Despite government vaccination efforts, these three viral diseases have become widespread in Egypt, with several reported epidemics. Egypt's importation of large numbers of animals from different countries, combined with unregulated animal movements through trading and borders between African countries and Egypt, facilitates the introduction of new FMDV serotypes and lineages not covered by the current vaccination plans. To establish an effective control program, countries need to assess the real epizootic situation of various infectious animal diseases to develop an efficient early warning system. This review provides information about FMD, LSD, and BEF, including their economic impacts, causative viruses, global burden, the situation in Egypt, and the challenges in controlling these diseases.

Development of two competitive ELISAs based on monoclonal antibodies for the serological detection of Bovine ephemeral fever virus

Bovine ephemeral fever virus (BEFV) is a member of the genus Ephemerovirus in the family Rhabdoviridae. It is an arthropod-borne virus transmitted by many species of midges and mosquitoes. It can cause severe economic consequences due to losses in milk production and the general condition of cattle and water buffalo. BEF occurs in some tropical, subtropical and warm temperate regions of Africa, Australia, the Middle East and Asia with seasonal outbreaks, but its possible spread to other areas (e.g. Europe) cannot be excluded. Therefore, using and developing rapid diagnostic methods with optimal performance is essential for identifying emerging pathogens and their control. In the present study, we developed two competitive serological ELISAs based on monoclonal antibodies (mAbs), designed by using BEFV inactivated antigen and the BEF recombinant nucleoprotein (N), respectively. A panel of 77 BEF-positive and 338 BEF-negative sera was used to evaluate the two tests. With a diagnostic sensitivity of 97.4 % using the inactivated virus and 98.7 % using the recombinant N, and a diagnostic specificity of 100 % using both antigens, our results suggest that these tests are suitable for the serological diagnosis of BEF.

Bovine Ephemeral Fever Viruses in Israel 2014-2023: Genetic Characterization of Local and Emerging Strains

Bovine ephemeral fever (BEF) is an arthropod-borne viral disease, which frequently causes significant epizootics in susceptible water buffalo and cattle in Africa, Australia, Asia and the Middle East. In the current study, a two-stage protocol for BEFV viral isolation was developed. Data on the clinical signs, geographic distribution and phylogenetic analysis of BEFV strains isolated in Israel in 2015, 2018, 2021 and 2023 were summarized. It was found that during 2015-2021, all BEF outbreaks were caused by local BEFV strains, whereas the epizootic of BEFV in 2023 was caused by a new "Mayotte-like" BEFV strain. A comparison of bluetongue (BT) and BEF outbreaks during 2023 in Israel demonstrated that the incidence of BEFV was 2.21 times higher and its pathogenicity was more serious for the cattle population compared to that caused by BTVs. A phylogenetic analysis of Israeli and global BEFV revealed the emergence of non-local strains in new areas. This finding suggests that BEFV can no longer be classified based only upon geographic distribution. Considering a phylogenetic, genetic and proteomic analysis of all available BEFV strains, we suggest classifying them as a single serotype, which includes four lineages.

Would you bet on the vet? Influences on dairy farmers' vaccination choices, with a spotlight on the Veterinarian impact

Ensuring effective vaccination is crucial for epidemic control, particularly in voluntary vaccination scenarios. Though highly important for planning voluntary vaccination programs, we lack insights into the effectiveness of veterinarian communication and the impact of disease-specific traits on farmer vaccination intentions. To fill this void, our study compared five diseases affecting Israeli dairy cattle (Botulism, Bovine Ephemeral Fever (BEF), Brucellosis, Lumpy Skin Disease (LSD), and Rabies). Using questionnaires grounded in the theory of planned behavior, we surveyed 340 Israeli dairy farmers to understand their vaccination intentions for each disease.Simultaneously, veterinarians overseeing these farms provided insights into their opinions and perceived influence on vaccination decisions. Results revealed varying levels of farmer vaccination intention, with Botulism showing the highest and BEF the lowest. Social pressure significantly influenced farmers' vaccination intentions, with distinct patterns across diseases. Veterinarian opinions had the highest influence only for LSD, while other factors played crucial roles in different diseases. Intriguingly, there was no correlation between veterinarians' recommendations and farmers' perceptions of these recommendations. In conclusion, the optimization of voluntary vaccination programs necessitates tailoring interventions to the unique characteristics of each disease. Additionally, improving communication between veterinarians and farmers is essential, with an emphasis on effective risk communication training.

An outbreak of Akabane disease in a cattle herd on the Mughan plain, Iran

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 co-seropositivity 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.

Risk analysis and seroprevalence of bovine ephemeral fever virus in Punjab, Pakistan

Bovine ephemeral fever (BEF) is a vector-borne viral disease caused by the RNA virus which belongs to the genus Ephemerovirus and the family Rhabdoviridae. To evaluate the effect of the risk factors like the breed of cattle and buffaloes, age, sex, lactation, housing and region on the bovine ephemeral fever virus (BEFV) prevalence, ELISA and virus neutralisation (VN) tests (n = 600) were performed for the BEFV prevalence. The seroprevalence in cattle was 45.6% and 42% by ELISA and VN, respectively (P = 0.001). The breed-wise seropositive ratio was (55-64%) in cattle and (22.5-18.3%) in buffaloes by VN and ELISA. The sex-wise prevalence was (40-49.4%) in females and (35.8-46%) in males by VN and ELISA in cattle and a similar prevalence was reported in buffaloes. The age-wise prevalence in bovines by ELISA was 5.33, 22.66 and 17.66% in the age group < 1 year, 1-3 years and > 3 years, respectively. The disease prevalence was higher in the age group of 1-3 years. The prevalence was higher during the 3rd lactation in bovines. The region-wise prevalence was higher in the 07 districts while lower (18-21%) in Rawalpindi District by VN and ELISA, respectively (P = 0.001). Commercial dairy farms of cattle showed a higher disease prevalence (52% and 44%) than non-commercial farms (38% and 36%) by ELISA and VN, respectively (P = 0.227). Exotic cows showed higher disease prevalence (76.67% and 70%) by ELISA and VN. The mortality in bovines was 5% (7.7% and 2.3%) in the cattle and buffaloes. The case fatality of BEFV in bovines was 12.25%. There was a significant effect of the risk factors like the breed, age, sex, lactation, housing and region on the BEFV prevalence. This is the first comprehensive study of BEFV in Pakistan.

An overview of the mosquitoes of Saudi Arabia (Diptera: Culicidae), with updated keys to the adult females

Despite the fact that mosquito-borne infections have considerable consequences for public health in Saudi Arabia, there is neither a thorough review of the species that occur in the country nor updated keys for the identification of the adult females. In this study, species accounts are given for 49 Saudi Arabian mosquito species, as well as Aedes albopictus (Skuse), which is not recorded in Saudi Arabia, but is medically important and is found in some countries of the Middle East and North Africa. Taxonomic notes provide additional information for certain taxa and/or aid their identification.

Economic Aspects of Bovine Ephemeral Fever (BEF) Outbreaks in Dairy Cattle Herds

Bovine ephemeral fever virus (BEFV) is an arthropod-borne virus (arbovirus) transmitted by blood-feeding insects (mosquitoes and Culicoides biting midges). While the dispersal of arboviral diseases such as bovine ephemeral fever (BEF) into naive areas is often the result of globalization and animal movement, the endemization and local outbreaks of these diseases are mainly influenced by environmental changes. Climate change affects the activity, distribution, dynamics, and life cycles of these vectors (arthropods), the replication of viruses within their vectors, and weakens animal's immune systems. Although BEF does not currently occur in the Americas and Europe (other than in the western regions of Turkey), the risk of BEFV emergence, spread, and endemization in Europe is real. Over the past two decades, arboviruses such as the bluetongue virus (BTV) and Schmallenberg virus (SBV) have emerged in Europe without warning and caused significant losses to the dairy and meat industries. Since the European cattle population has never been exposed to BEFV, the economic losses to dairy and beef production in this continent due to the reduction in milk production, loss of valuable cows, and abortion, should BEF emerge, would probably be considerable. Moreover, arboviruses can also cause substantial financial damage due to restrictions on animal trade and transportation, like the current EHDV-8 outbreak in the Mediterranean basin. In this study, we used national data stored in the Israeli herd book to examine the economic aspects of BEF outbreaks in affected dairy cattle farms countrywide. Our results demonstrate that BEF outbreaks can have immediate and delayed effects, causing severe economic losses due to culling (loss of valuable cows) and a reduction in milk production that affects dairy farm income for months after clinical diagnosis. To our knowledge, this is the first extensive study on the impact of a BEF outbreak at a population level, enabling to conduct accurate risk assessments in future cases of BEFV emergence and re-emergence.

Comprehensive examination on codon usage bias pattern of the Bovine Ephemeral fever virus

Bovine Ephemeral Fever Virus (BEFV) is a non-contagious virus that commonly infects cattle and water buffalo, reduces milk productivity, decreases the quality of beef, and causes an adverse economic impact on the global livestock industry. However, the evolution of BEFV is unclear, and uncertainty exists regarding its global geodynamics. Consequently, this study aims to comprehend the pattern of viral evolution and gene expression in the BEFV genes G, M, N, and P, including synonymous codons. Additionally, we performed recombination analyses, which exclusively detected recombination signals in the G- and P-genes. Subsequently, a phylogenetic tree was constructed to validate and support these findings. The codon usage bias results showed that the BEFV-selected genes were influenced by both natural and mutation pressure. Furthermore, nucleotide A is more abundant in all the selected genes. The eNC values, ranging from 42.99 to 47.10, revealed the presence of moderate codon usage bias, where gene P exhibited the highest and gene G had the lowest codon usage bias. The neutrality and PR-2 plots, specified codon usage patterns of the genes, are also being shaped by strong selectional pressure. This comprehensive analysis of BEFV genes (G, M, N, and P) sheds light on the molecular evolutionary patterns, co-adaptation, and different genes expression in diverse regions, facilitating the development of preventative programs and insights into viral pathogenesis and vaccine design.Communicated by Ramaswamy H. Sarma.

Hefer valley virus: a novel ephemerovirus detected in the blood of a cow with severe clinical signs in Israel in 2022

A novel ephemerovirus was identified in a Holstein-Friesian cow in the Hefer Valley, Israel, that showed severe and fatal clinical signs resembling an arboviral infection. A sample taken during the acute phase tested negative for important endemic arboviral infectious cattle diseases. However, sequencing from blood revealed the full genome sequence of Hefer Valley virus, which is likely to represent a new species within the genus Ephemerovirus, family Rhabdoviridae. Archived samples from cattle with comparable clinical signs collected in Israel in 2021 and 2022 tested negative for the novel virus, and therefore, the actual distribution of the virus is unknown. As this is a recently identified new viral infection, the viral vector and the prevalence of the virus in the cattle population are still unknown but will be the subject of future investigations.

Effectiveness of the strain 919 bovine ephemeral fever virus vaccine in the face of a real-world outbreak: A field study in Israeli dairy herds

Bovine ephemeral fever virus (BEFV) is a globally spread arthropod-borne RNA virus that has significant economic impacts on the cattle industry. A live attenuated commercial BEF vaccine, based on the Australian BEFV strain 919, is widely used in Israel and other countries. A previous study has suggested the high effectiveness of this vaccine (ULTRAVAC BEF VACCINE™ from Zoetis®), but anecdotal reports of high BEF morbidity among vaccinated dairy herds in Israel casted doubt on these findings. To resolve this uncertainty, a randomized controlled field vaccine effectiveness study was conducted in Israel during a BEF outbreak which occurred in 2021. Eleven dairy herds were enrolled and monitored for BEF-associated morbidity and rumination alteration patterns using electronic monitoring tags (HR Tags, SCR® Dairy, Netanya, Israel). Four of the herds were naturally infected with BEFV during the outbreak, resulting in a total of 120 vaccinated and 311 unvaccinated subjects that were included in the effectiveness study. A mixed-effect Cox proportional hazard regression model was used to calculate the overall hazard ratio between vaccinated and unvaccinated cattle. This analysis demonstrated an average vaccine effectiveness of 60 % (95 % CI = 38 %-77 %) for preventing clinical disease. In addition, a non-statistically significant trend (p = 0.1) towards protection from mortality was observed, with no observation of mortality among the vaccinated groups compared to 2.61 % mortality (7/311) among the unvaccinated subjects. One hundred and thirty vaccinated and unvaccinated calves from affected and non-affected herds and with different status of morbidity were sampled and analysed by serum-neutralization test. The highest titers of BEFV-neutralizing antibodies were found in subjects that were both vaccinated and clinically affected, indicating a booster effect after vaccination. The results of the study provide evidence for the moderate effectiveness of the ULTRAVAC BEF VACCINE™ for the prevention of BEF.

Whole genome characterization and evolutionary analysis of bovine ephemeral fever virus isolated in Iran

Bovine ephemeral fever virus (BEFV) is an economically important arthropod-borne virus of cattle and water buffaloes which is enzootic in Africa, Australia, and Asia. We characterized the entire length of BEFV BA/RZ/IR strain genome isolated in Iran and compared to the all BEFV full genomes available in the GenBank. The BEFV genomes were phylogenetically classified as 4 lineages including the Middle Eastern, East Asian, Australian, and South African lineages. The Iranian BA/RZ/IR strain, which displayed maximum sequence identity (96.72%) to the Chinese JT02L strain was clustered as a separate branch in the East Asian lineage of the virus. Using Shannon entropy analysis, amino acid variations were detected in the all proteins encoded by BEFV genomes. Particularly, the polymerase L and the accessory proteins Gns, α2 and β exhibited the highest amino acid variations suggesting their significance in the viral replication efficiency. Our bioinformatics analyses also predict the occurrence of recombination event within the East Asian lineage of BEFV genomes. Our data show that the Chinese Henan 1 may be a hybrid strain constructed of the Chinese JT02L and Iranian BA/RZ/IR BEFV strains as the major and minor parents, respectively. These computational analyses suggest that the homologous recombination may be an evolutionary mechanism for BEFV as a member of the Rhabdoviridae family.

Evaluation of antibody response to inactivated bovine ephemeral fever virus vaccine for Japanese Black calves in the field

The purpose of this study was to investigate the antibody response to the bovine ephemeral fever virus (BEFV) vaccine in Japanese Black calves. Twenty-eight Japanese Black calves, which were raised on an ordinal farm, were divided into two groups. Fifteen calves received the inactivated BEFV vaccine at 12 and 16 weeks of age (vaccination group), and 13 calves did not receive the vaccine (non-vaccination group). Blood samples were obtained at 0, 4, 8, 12, 16, 20, 24, 28, and 32 weeks of age. As the results, in the vaccination group, the antibody titers at 16, 20, 24, 28, and 32 weeks of age were significantly higher than those at 0, 4, 8, and 12 weeks of age (p < 0.01). Additionally, antibody titer in the vaccination group increased after 16 weeks of age and showed a significantly higher level than that in the non-vaccination group throughout the remaining experimental period (p < 0.01). These results might be helpful in establishing a vaccination program against BEFV in calves.

Emergence and genomic analysis of a novel sublineage of bovine ephemeral fever virus in Southwest China

Introduction

Bovine ephemeral fever virus (BEFV), belonging to the genus Ephemerovirus under the family Rhabdoviridae, is the etiological cause for the bovine ephemeral fever (BEF) in cattle and water buffalo.

Methods

In this study, we report recent BEF outbreaks in Southwest China and sequence the complete genome sequence of one BEFV isolate BEFV/CQ1/2022.

Results and Discussion

Comparative genomic analyses between BEFV/CQ1/2022 and isolates available in GenBank revealed remarkable inter-isolate divergence. Meanwhile, the sequence divergence was related to the evolutionary relationships and geographical distribution of the isolates. Phylogenetic analysis indicated that the global BEFV isolates can be divided into 4 distinct lineages. The East Asia lineage was the most diverse and could be subdivided into 4 sublineages. Notably, BEFV/CQ1/2022 and other 10 recent isolates from Mainland China were found to be clustered in sublineage 2. Additionally, recombination analysis provided evidence of BEFV recombination among East Asian isolates for the first time. Taken together, a novel sublineage of the East Asian BEFV emerged in Southwest China, and large divergence and potential recombination among BEFV strains were investigated in this study, which may improve understanding of BEFV epidemiology and evolution.

Finding potential inhibitors against RNA-dependent RNA polymerase (RdRp) of bovine ephemeral fever virus (BEFV): an in-silico study

The bovine ephemeral fever virus (BEFV) is an enzootic agent that affects millions of bovines and causes major economic losses. Though the virus is seasonally reported with a very high morbidity rate (80-100%) from African, Australian, and Asiatic continents, it remains a neglected pathogen in many of its endemic areas, with no proper therapeutic drugs or vaccines presently available for treatment. The RNA-dependent RNA polymerase (RdRp) catalyzes the viral RNA synthesis and is an appropriate candidate for antiviral drug developments. We utilized integrated computational tools to build the 3D model of BEFV-RdRp and then predicted its probable active binding sites. The virtual screening and optimization against these active sites, using several small-molecule inhibitors from a different category of Life Chemical database and FDA-approved drugs from the ZINC database, was performed. We found nine molecules that have docking scores varying between -6.84 to -10.43 kcal/mol. Furthermore, these complexes were analyzed for their conformational dynamics and thermodynamic stability using molecular dynamics simulations in conjunction with the molecular mechanics generalized Born surface area (MM-GBSA) scheme. The binding free energy calculations depict that the electrostatic interactions play a dominant role in the RdRp-inhibitor binding. The hot spot residues, such as Arg565, Asp631, Glu633, Asp740, and Glu707, were found to control the RdRp-inhibitor interaction. The ADMET analysis strongly suggests favorable pharmacokinetics of these compounds that may prove useful for treating the BEFV ailment. Overall, we anticipate that these findings would help explore and develop a wide range of anti-BEFV therapy.Communicated by Ramaswamy H. Sarma.

Isolation of a novel rhabdovirus and detection of multiple novel viral sequences in Culex species mosquitoes in the United States

To increase our understanding of the diversity of the mosquito virome, 6956 mosquitoes of five species (Culex erraticus, Culex pipiens, Culex restuans, Culex tarsalis, and Culex territans) collected in Iowa in the United States in 2017 and 2020 were assayed for novel viruses by performing polyethylene glycol precipitation, virus isolation in cell culture, and unbiased high-throughput sequencing. A novel virus, provisionally named "Walnut Creek virus", was isolated from Cx. tarsalis, and its genomic sequence and organization are characteristic of viruses in the genus Hapavirus (family Rhabdoviridae). Replication of Walnut Creek virus occurred in avian, mammalian, and mosquito, but not tick, cell lines. A novel virus was also isolated from Cx. restuans, and partial genome sequencing revealed that it is distantly related to an unclassified virus of the genus Phytoreovirus (family Sedoreoviridae). Two recognized viruses were also isolated: Culex Y virus (family Birnaviridae) and Houston virus (family Mesoniviridae). We also identified sequences of eight novel viruses from six families (Amalgaviridae, Birnaviridae, Partitiviridae, Sedoreoviridae, Tombusviridae, and Totiviridae), two viruses that do not belong to any established families, and many previously recognized viruses. In summary, we provide evidence of multiple novel and recognized viruses in Culex spp. mosquitoes in the United States.

Development and validation of a DIVA ELISA for differentiating BEFV infected from vaccinated animals

Inactivated vaccine is considered safe and used for prevention of bovine ephemeral fever in several endemic countries. To differentiate between BEFV-infected and vaccinated animals, we developed an ELISA capable of detecting infection-related antibodies against BEFV. Recombinant proteins, including N, P, M, L, G_NS, α2, β and γ, were expressed in E. coli and screened by Western blotting and ELISA. The results showed G_NS, α2 and β specifically reacted with sera from BEFV infected cattle but not sera from vaccinated cattle. A DIVA ELISA based on a C-terminal truncated form of G_NS was developed, with 100% sensitivity and 98.0% specificity at a sample to positive-control optical density ratio (S/P) threshold of 0.18. Specificity analysis showed that the assay has no cross-reactivity with antisera of other common bovine viruses. Anti-G_NS antibody appears at 3-4 days post infection (dpi) and persists up to 240-300 dpi in the experimentally infected cattle. Sero-epidemiological survey using sera collected from vaccinated cattle in an endemic area in Jiangsu Province revealed sero-positive rate of 2.36% (6/254), indicating that the DIVA ELISA could be used as a reliable diagnostic tool for differentiating BEFV infected from vaccinated animals.

Molecular epidemiology of Akabane virus in Taiwan

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.

North American Arboviruses and White-Tailed Deer (Odocoileus virginianus): Associated Diseases and Role in Transmission

Background: Arboviral disease is of increasing concern to human and animal health professionals as emerging and re-emerging arboviruses are more frequently recognized. Wildlife species are known to play a role in the transmission and maintenance of arboviruses and infections can result in morbidity and mortality in wildlife hosts. Materials and Methods: In this review, we detail existing evidence of white-tailed deer (Odocoileus virginianus) as an important host to a diverse collection of arboviruses and evaluate the utility of this species as a resource to better understand the epidemiology of related viral diseases. Results: Relevant veterinary and zoonotic viral pathogens endemic to North America include epizootic hemorrhagic disease virus, bluetongue virus, orthobunyaviruses, vesicular stomatitis virus, Eastern equine encephalitis virus, West Nile virus, and Powassan virus. Exotic viral pathogens that may infect white-tailed deer are also identified with an emphasis on zoonotic disease risks. The utility of this species is attributed to the high degree of contact with humans and domestic livestock and evidence of preferential feeding by various insect vectors. Conclusions: There is mounting evidence that white-tailed deer are a useful, widely available source of information regarding arboviral circulation, and that surveillance and monitoring of deer populations would be of value to the understanding of certain viral transmission dynamics, with implications for improving human and domestic animal health.

Identification of two novel ephemeroviruses in pigs infected by classical swine fever virus

Ephemeroviruses are arthropod-borne rhabdoviruses within Ephemerovirus genus and have been isolated exclusively from cattle and haematophagous arthropods (mosquitoes and biting midges) without any member detected or isolated up to date from pigs, although some serological surveys have indicated that pigs may be a silent host for ephemerovirus infection. Here, many viral reads annotated to, but genetically distinct from, the existing members within the Ephemerovirus genus have been identified in the meta-transcriptomic data of two clinical classical swine fever virus (CSFV)-infected samples (HeN10 and GDMM7). The nearly complete genome sequences of the two novel ephemeroviruses have been obtained through contig assembly, specific RT-PCR and sequencing, therefore named as porcine ephemeroviruses (PoEVs). Genome nucleotide sequence analysis showed that PoEV strains HeN10 and GDMM7 have similar genome organization and 66.5% genomic identity to each other, but both are genetically distant from all members of the Ephemerovirus genus with identity being only 51.1-59.6%. Furthermore, comparison of the most conserved ephemeroviral proteins N and L indicated that PoEV strains HeN10 and GDMM7 share a high sequence identity to each other (N: 78.1%; L: 70.7%), but are diverged from the known ephemeroviruses (N: 43.4-60.7%; L: 47.6-58.5%). The genetic distance is significantly beyond the criteria for demarcation of viruses assigned to different ephemerovirus species. Thereby, two novel viruses named as PoEV1 (strain HeN10) and PoEV2 (strain GDMM7) are identified and these appear to represent two new species within the Ephemerovirus genus. The present study showed the first genome evidence of pig ephemeroviruses, likely expanding the known host range of ephemerovirus.

Vector-Borne Viral Diseases as a Current Threat for Human and Animal Health—One Health Perspective

Over the last decades, an increase in the emergence or re-emergence of arthropod-borne viruses has been observed in many regions. Viruses such as dengue, yellow fever, or zika are a threat for millions of people on different continents. On the other hand, some arboviruses are still described as endemic, however, they could become more important in the near future. Additionally, there is a group of arboviruses that, although important for animal breeding, are not a direct threat for human health. Those include, e.g., Schmallenberg, bluetongue, or African swine fever viruses. This review focuses on arboviruses and their major vectors: mosquitoes, ticks, biting midges, and sandflies. We discuss the current knowledge on arbovirus transmission, ecology, and methods of prevention. As arboviruses are a challenge to both human and animal health, successful prevention and control are therefore only possible through a One Health perspective.

Insights on Transmission, Spread, and Possible Endemization of Selected Arboviruses in Israel—Interim Results from Five-Year Surveillance

Outbreaks of arthropod-borne (arbo) viruses that infect livestock impact the health and welfare of domestic and wild animals are often responsible for significant economic losses in livestock production. Surveillance and early warning systems effectively predict the emergence and re-emergence of arboviral disease. This paper presents the interim results of five years monitoring the exposure of sentinel naïve heifers and Culicoides biting midges (Diptera; Ceratopogonidae) to bovine ephemeral fever virus (BEFV), Simbu serogroup viruses, bluetongue viruses (BTV), and epizootic hemorrhagic disease viruses (EHDV). The data were collected from 11 dairy farms situated within eight different geographical regions in Israel. The results indicate that cattle in Israel are affected by all four viruses from the early summer onward. The investigated viruses exhibit unique site-specific profiles in both ruminants and vectors. The potential of several vectors to transmit these viruses and lack of cross-protection to re-infection with multiple serotypes (BTV and EHDV) or species (Simbu serogroup viruses) highlights some likely mechanisms that may play a role in these viruses’ maintenance cycle and possible endemization in our region.

Molecular characterization and phylogenetic analysis of bovine ephemeral fever viruses in Khuzestan province of Iran in 2018 and 2020

BACKGROUND

Bovine ephemeral fever (BEF) is an arthropod-borne viral disease caused by the BEF virus (BEFV). This single-stranded RNA virus that affects cattle and water buffalo is endemic in tropical and subtropical regions including Iran. While BEF is a major disease of cattle in Iran, information regarding its agent, molecular characterization, and circulating viruses are highly limited. The current study aimed to, firstly, determine the genetic and antigenic characteristics of BEFV strains in Khuzestan province in Southwest of Iran in 2018 and 2020 and, secondly, to compare them with strains obtained from other areas.

RESULTS

By phylogenetic analysis based on the Glycoprotein gene, BEFV strains were divided into four clusters of Middle East, East Asia, South Africa, and Australia; in which the 2018 and 2020 Iranian BEFV strains were grouped in the Middle East cluster with the Turkish, Indian, and Israeli strains. Depending on the chronology and geographical area, the outbreaks of Turkey (2020), Iran (2018 and 2020), and India (2018 and 2019) are proposed to be related. These BEFVs had the highest identity matrix and the lowest evolutionary distance among the studied strains. Multiple sequence alignment of G1, G2, and G3 antigenic sites showed that these neutralizing epitopes are highly conserved among the strains of the Middle East cluster; however, the strains previously identified in Iran differed in three amino acids placed in G1 and G2 epitopes.

CONCLUSION

The findings revealed that BEFVs circulating in the Middle East are closely related phylogenetically and geographically. They also have similar antigenic structures; therefore, developing a vaccine based on these strains can be effective for controlling BEF in the Middle East.

Identification of Cytotoxic T lymphocyte (CTL) Epitope and design of an immunogenic multi-epitope of Bovine Ephemeral Fever Virus (BEFV) Glycoprotein G for Vaccine Development

Bovine ephemeral fever (BEF), a vector-borne disease of cattle and water buffalo, is enzootic in tropical and subtropical zones of Asia, Australia, and Africa. Since cytotoxic T lymphocytes (CTL) responses may play a key role in the control of bovine ephemeral fever virus (BEFV) infection, it is important to identify and characterize the CTL target epitopes of BEFV antigens. The current study has been designed to identify and characterize the potential CTL epitopes using the Immuno-informatics tools, and it helped find the potent vaccine candidates against BEF. Antigenicity, toxicity, allergenicity, and immunogenicity testing of predicted CTL epitopes was done. Total four CTL epitopes for BEFV G protein, have been identified as potential epitopes. Prediction of the 3D structure of multi-epitope (final structure) was performed using I-TASSER server. Model 1 was selected as the best model with C-Score: -3.71. The modeled G protein structure and multi-epitope structure were validated by the Ramachandran plots Prosa and Verify 3D server. Epitopic regions of 3D protein structure were identified by Chimera UCSF software. Physicochemical properties of the Multi epitope were evaluated using ProtParam server. This is the first report of CTL epitope in the G protein of BEFV. In this manner, they would play an important role in evoking the immune response as well as vaccine development. However, in vitro and in vivo experimental studies are required for suggested epitopes verification. The multi-epitope was designed from regions of the G protein sequence that lacked mutation and genomic diversity. Therefore, it can be introduced as a protein vaccine from all strains of BEFV as a vaccine candidate for design.

Genome-scale molecular and phylogenetic characterization of Middle Point orbiviruses from Australia

Middle Point orbivirus (MPOV) is an Australian arbovirus, belongs to the Yunnan orbivirus species found in China. First detected and reported from Beatrice Hill, Northern Territory (NT), MPOV has to date, only been exclusively reported from the NT, Australia. Whilst genetic characterization of MPOV has been previously described, only restricted to sequence information for segments 2 and 3 coding core protein VP2 and outer capsid protein VP3, respectively. This study presents for the first time nearly full-length genome sequences of MPOV, which represent 24 isolates collected over a span of more than 20 years from 1997 to 2018. Whilst the majority of isolates were sampled at Beatrice Hill, NT where MPOV is most frequently isolated, this report also describes the first two isolations of MPOV from Queensland (QLD), Australia. One of which is the first non-bovine isolate obtained from the mosquito vector Aedes vittiger. We further compared these MPOV sequences with known sequences of the Yunnan orbivirus and other known orbivirus sequences of mosquito origin found in Australia. The phylogenetic analyses indicate the Australian MPOV sequences are more closely related to each other than other known sequences of Yunnan orbivirus. Furthermore, MPOV sequences are closely related to sequences from the Indonesian isolate JKT-8650. The clustering of Australian sequences in the phylogenetic tree suggests the monophyletic lineage of MPOV circulating in Australia. Further, ongoing surveillance is required to assess the existence and prevalence of this or other yet undetected lineages of MPOV and other orbiviruses in Australia.

Complete genome sequencing and assessment of mutation-associated protein dynamics of the first Indian bovine ephemeral fever virus (BEFV) isolate

Background

Bovine ephemeral fever (BEF) is a re-emerging disease caused by bovine ephemeral fever virus (BEFV). Although it poses a huge economic threat to the livestock sector, complete viral genome information from any South Asian country, including India, lacks.

Aim

Genome characterization of the first Indian BEFV isolate and to evaluate its genetic diversity by characterizing genomic mutations and their associated protein dynamics.

Materials and Methods

Of the nineteen positive blood samples collected from BEF symptomatic animals during the 2018-19 outbreaks in India, one random sample was used to amplify the entire viral genome by RT-PCR. Utilizing Sanger sequencing and NGS technology, a complete genome was determined. Genome characterization, genetic diversity and phylogenetic analyses were explored by comparing the results with available global isolates. Additionally, unique genomic mutations within the Indian isolate were investigated, followed by in-silico assessment of non-synonymous (NS) mutations impacts on corresponding proteins’ secondary structure, solvent accessibility and dynamics.

Results

The complete genome of Indian BEFV has 14,903 nucleotides with 33% GC with considerable genetic diversity. Its sequence comparison and phylogenetic analysis revealed a close relatedness to the Middle Eastern lineage. Genome-wide scanning elucidated 30 unique mutations, including 10 NS mutations in the P, L and G_NS proteins. The mutational impact evaluation confirmed alterations in protein structure and dynamics, with minimal effect on solvent accessibility. Additionally, alteration in the interatomic interactions was compared against the wild type.

Conclusion

These findings extend our understanding of the BEFV epidemiological and pathogenic potential, aiding in developing better therapeutic and preventive interventions.

The Development of Dual Vaccines against Lumpy Skin Disease (LSD) and Bovine Ephemeral Fever (BEF)

Dual vaccines (n = 6) against both lumpy skin disease (LSD) and bovine ephemeral fever (BEF) were constructed, based on the BEFV glycoprotein (G) gene, with or without the BEFV matrix (M) protein gene, inserted into one of two different LSDV backbones, nLSDV∆SOD-UCT or nLSDVSODis-UCT. The inserted gene cassettes were confirmed by PCR; and BEFV protein was shown to be expressed by immunofluorescence. The candidate dual vaccines were initially tested in a rabbit model; neutralization assays using the South African BEFV vaccine (B-Phemeral) strain showed an African consensus G protein gene (Gb) to give superior neutralization compared to the Australian (Ga) gene. The two LSDV backbones expressing both Gb and M BEFV genes were tested in cattle and shown to elicit neutralizing responses to LSDV as well as BEFV after two inoculations 4 weeks apart. The vaccines were safe in cattle and all vaccinated animals were protected against virulent LSDV challenge, unlike a group of control naïve animals, which developed clinical LSD. Both neutralizing and T cell responses to LSDV were stimulated upon challenge. After two inoculations, all vaccinated animals produced BEFV neutralizing antibodies ≥ 1/20, which is considered protective for BEF.

Immunoinformatics Approach to Design Multi-Epitope- Subunit Vaccine against Bovine Ephemeral Fever Disease

Bovine ephemeral fever virus (BEFV) is an overlooked pathogen, recently gaining widespread attention owing to its associated enormous economic impacts affecting the global livestock industries. High endemicity with rapid spread and morbidity greatly impacts bovine species, demanding adequate attention towards BEFV prophylaxis. Currently, a few suboptimum vaccines are prevailing, but were confined to local strains with limited protection. Therefore, we designed a highly efficacious multi-epitope vaccine candidate targeted against the geographically distributed BEFV population. By utilizing immunoinformatics technology, all structural proteins were targeted for B- and T-cell epitope prediction against the entire allele population of BoLA molecules. Prioritized epitopes were adjoined by linkers and adjuvants to effectively induce both cellular and humoral immune responses in bovine. Subsequently, the in silico construct was characterized for its physicochemical parameters, high immunogenicity, least allergenicity, and non-toxicity. The 3D modeling, refinement, and validation of ligand (vaccine construct) and receptor (bovine TLR7) then followed molecular docking and molecular dynamic simulation to validate their stable interactions. Moreover, in silico cloning of codon-optimized vaccine construct in the prokaryotic expression vector (pET28a) was explored. This is the first time HTL epitopes have been predicted using bovine datasets. We anticipate that the designed construct could be an effective prophylactic remedy for the BEF disease that may pave the way for future laboratory experiments.

The role of wildlife in the epidemiology and control of Foot-and-mouth-disease And Similar Transboundary (FAST) animal diseases: A review

Transboundary Animal Diseases (TADs) are notifiable diseases which are highly transmissible and have the potential for rapid spread regardless of national borders. Many TADs are shared between domestic animals and wildlife, with the potential to affect both livestock sector and wildlife conservation and eventually, public health in the case of zoonosis. The European Commission for the Control of Foot-and-Mouth Disease (EuFMD), a commission of the Food and Agriculture Organization of the United Nations (FAO), has grouped six TADs as 'Foot-and-mouth disease (FMD) And Similar Transboundary animal diseases' (FAST diseases). FAST diseases are ruminant infections caused by viruses, for which vaccination is a control option. The EuFMD hold-FAST strategy aims primarily at addressing the threat represented by FAST diseases for Europe. Prevention and control of FAST diseases might benefit from assessing the role of wildlife. We reviewed the role of wildlife as indicators, victims, bridge hosts or maintenance hosts for the six TADs included in the EuFMD hold-FAST strategy: FMD, peste des petits ruminants, lumpy skin disease, sheep and goatpox, Rift Valley fever and bovine ephemeral fever. We observed that wildlife can act as indicator species. In addition, they are occasionally victims of disease outbreaks, and they are often relevant for disease management as either bridge or maintenance hosts. Wildlife deserves to become a key component of future integrated surveillance and disease control strategies in an ever-changing world. It is advisable to increase our knowledge on wildlife roles in relevant TADs to improve our preparedness in case of an outbreak in previously disease-free regions, where wildlife may be significant for disease surveillance and control.

A Senescence-Like Cellular Response Inhibits Bovine Ephemeral Fever Virus Proliferation

During industrial-scale production of viruses for vaccine manufacturing, anti-viral response of host cells can dampen maximal viral antigen yield. In addition to interferon responses, many other cellular responses, such as the AMPK signaling pathway or senescence-like response may inhibit or slow down virus amplification in the cell culture system. In this study, we first performed a Gene Set Enrichment Analysis of the whole-genome mRNA transcriptome and found a senescence-like cellular response in BHK-21 cells when infected with bovine ephemeral fever virus (BEFV). To demonstrate that this senescence-like state may reduce virus growth, BHK-21 subclones showing varying degrees of a senescence-like state were infected with BEFV. The results showed that the BHK-21 subclones showing high senescence staining could inhibit BEFV replication while low senescence-staining subclones are permissive to virus replication. Using a different approach, a senescence-like state was induced in BHK-21 using a small molecule, camptothecin (CPT), and BEFV susceptibility were examined. The results showed that CPT-treated BHK-21 is more resistant to virus infection. Overall, these results indicate that a senescence-like response may be at play in BHK-21 upon virus infection. Furthermore, cell clone selection and modulating treatments using small molecules may be tools in countering anti-viral responses.

Bta-miR-101 suppresses BEFV replication via targeting NKRF

MicroRNAs (miRNAs), as a kind of small noncoding RNAs, have been proved to play a regulatory role in virus infection. However, the role and mechanism of cellular miRNAs in bovine transient fever virus (BEFV) infection are largely unknown. In the present study, we found that bta-miR-101 was significantly up-regulated in the Madin-Darby Bovine Kidney (MDBK) cells upon BEFV infection. Notably, bta-miR-101 mimic dramatically inhibited BEFV replication, while bta-miR-101 inhibitor facilitated BEFV replication, suggesting that bta-miR-101 acted as an anti-viral host factor restraining BEFV replication. Subsequently, NF-κB repressing factor (NKRF) was identified as a target gene of bta-miR-101 by dual luciferase reporter assay, and bta-miR-101 mimic significantly down-regulated expression of NKRF, while bta-miR-101 inhibitor up-regulated its expression, respectively. Furthermore, NKRF could induce apoptosis, and favored the replication of BEFV. Finally, bta-miR-101 inhibited BEFV-induced apoptosis via targeting NKRF to suppress virus replication. In general, our study provides a novel mechanism for bta-miR-101 to exert its antiviral function, which provides a theoretical basis for the development of antiviral strategy.

Isolation and genetic characterization of bovine ephemeral fever virus from epidemic-2020 in Turkey

Bovine ephemeral fever virus (BEFV) infection occurs seasonally in many tropical and subtropical regions of Africa, Asia (including the Middle East), and Australia while it is exotic in Europe. In this study, the epidemiology of BEFV infection in Turkey that bridges southeastern Europe and Asia, geographically, was investigated according to the comparison of the nucleotide sequences of the virus caused the last epidemic in 2020 with those of the strains previously detected in Turkey as well as BEFV strains from other countries. In the phylogenetic analysis, based on an alignment of full-length G gene sequences, BEFVs from epidemic-2020 were located in Middle Eastern lineage and appear to represent most closely related BEFVs from India-2018 and 2019. The findings will contribute to a better understanding of BEFV epidemiology in Turkey.

Expression and immunogenicity of secreted forms of bovine ephemeral fever virus glycoproteins applied to subunit vaccine development

AIMS

Vaccines for bovine ephemeral fever virus (BEFV) are available but are difficult to produce, expensive or suffer from genetic instability. Therefore, we designed constructs encoding C-terminally truncated forms (transmembrane anchoring region deleted) of glycoproteins G and G_NS such that they were secreted from the cell into the media to achieve high-level antigen expression, correct glycosylation pattern and enable further simple purification with the V5 epitope tag.

METHODS AND RESULTS

In this study, synthetic biology was employed to create membrane-bound and secreted forms of G and G_NS glycoprotein. Mammalian cell culture was employed as an antigen expression platform, and the secreted forms of G and G_NS protein were easily purified from media using a highly effective, single-step method. The V5 epitope tag was genetically fused to the C-termini of the proteins, enabling detection of the antigen through immunoblotting and immunomicroscopy. Our data demonstrated that the C-terminally truncated form of the G glycoprotein was efficiently secreted from cells into the cell media. Moreover the immunogenicity was confirmed in mice test.

CONCLUSIONS

The immuno-dot blots showed that the truncated G glycoprotein was present in the total cell extract, and was clearly secreted into the media, consistent with the western blotting data and live-cell images. Our strategy presented the expression of secreted, epitope-tagged, forms of the BEFV glycoproteins such that appropriately glycosylated forms of BEFV G protein was secreted from the BHK-21 cells. This indicates that high-level expression of secreted G glycoprotein is a feasible strategy for large-scale production of vaccines and improving vaccine efficacy.

SIGNIFICANCE AND IMPACT OF THE STUDY

The antigen expression strategy designed in this study can produce high-quality recombinant protein and reduce the amount of antigen used in the vaccine.

Investigation of bovine ephemeral fever virus transmission by putative dipteran vectors under experimental conditions

BACKGROUND

Bovine ephemeral fever virus (Rhabdoviridae: Ephemerovirus) (BEFV) causes bovine ephemeral fever (BEF), an economically important disease of cattle and water buffalo. Outbreaks of BEF in Africa, Australia, Asia and the Middle East are characterized by high rates of morbidity and highly efficient transmission between cattle hosts. Despite this, the vectors of BEFV remain poorly defined.

METHODS

Colony lines of biting midges (Culicoides sonorensis) and mosquitoes (Aedes aegypti, Culex pipiens and Culex quinquefasciatus) were infected with a strain of BEFV originating from Israel by feeding on blood-virus suspensions and by intrathoracic inoculation. In addition, in vivo transmission of BEFV was also assessed by allowing C. sonorensis inoculated by the intrathoracic route to feed on male 6 month-old Holstein-Friesian calves.

RESULTS

There was no evidence of BEFV replication within mosquitoes fed on blood/virus suspensions for mosquitoes of any species tested for each of the three colony lines. In 170 C. sonorensis fed on the blood/virus suspension, BEFV RNA was detected in the bodies of 13 individuals and in the heads of two individuals, indicative of fully disseminated infections and an oral susceptibility rate of 1.2%. BEFV RNA replication was further demonstrated in all C. sonorensis that were inoculated by the intrathoracic route with virus after 5, 6 or 7 days post-infection. Despite this, transmission of BEFV could not be demonstrated when infected C. sonorensis were allowed to feed on calves.

CONCLUSIONS

No evidence for infection or dissemination of BEFV (bovine/Israel/2005-6) in mosquitoes of three different species was found. Evidence was found for infection of C. sonorensis by the oral route. However, attempts to transmit BEFV to calves from infected C. sonorensis failed. These results highlight the challenge of defining the natural vector of BEFV and of establishing an in vivo transmission model. The results are discussed with reference to the translation of laboratory-based studies to inference of vector competence in the field.

Aspirin and 5-Aminoimidazole-4-carboxamide Riboside Attenuate Bovine Ephemeral Fever Virus Replication by Inhibiting BEFV-Induced Autophagy

Recent study in our laboratory has demonstrated that BEFV-induced autophagy via activation of the PI3K/Akt/NF-κB and Src/JNK pathways and suppression of the PI3K-AKt-mTORC1 pathway is beneficial for virus replication. In the current study, we found that both aspirin and 5-aminoimidazole-4-carboxamide-1-β-riboside (AICAR) siginificantly attenuated virus replication by inhibiting BEFV-induced autophagy via suppressing the BEFV-activated PI3K/Akt/NF-κB and Src/JNK pathways as well as inducing reversion of the BEFV-suppressed PI3K-Akt-mTORC1 pathway. AICAR reversed the BEFV-activated PI3K/Akt/NF-κB and Src/JNK pathways at the early to late stages of infection and induced reversion of the BEFV-suppressed PI3K-AKt-mTORC1 pathway at the late stage of infection. Our findings reveal that inhibition of BEFV-induced autophagy by AICAR is independent of AMPK. Furthermore, we found that AICAR transcriptionally downregulates the ATG related genes ULK1, Beclin 1, and LC3 and enhances Atg7 degradation by the proteasome pathway. Aspirin suppresses virus replication by inhibiting BEFV-induced autophagy. It directly suppressed the NF-κB pathway and reversed the BEFV-activated Src/JNK pathway at the early stage of infection and reversed the BEFV-suppressed PI3K/Akt/mTOR pathway at the late stage of infection. The current study provides mechanistic insights into the effects of aspirin and AICAR on BEFV replication through suppression of BEFV-induced autophagy.

Wolbachia: A tool for livestock ectoparasite control

Ectoparasites and livestock-associated insects are a major concern throughout the world because of their economic and welfare impacts. Effective control is challenging and relies mainly on the use of chemical insecticides and acaricides. Wolbachia, an arthropod and nematode-infecting, maternally-transmitted endosymbiont is currently of widespread interest for use in novel strategies for the control of a range of arthropod-vectored human diseases and plant pests but to date has received only limited consideration for use in the control of diseases of veterinary concern. Here, we review the currently available information on Wolbachia in veterinary ectoparasites and disease vectors, consider the feasibility for use of Wolbachia in the control of livestock pests and diseases and highlight critical issues which need further investigation.

Annexin A2 gene interacting with viral matrix protein to promote bovine ephemeral fever virus release

Bovine ephemeral fever virus (BEFV) causes bovine ephemeral fever, which can produce considerable economic damage to the cattle industry. However, there is limited experimental evidence regarding the underlying mechanisms of BEFV. Annexin A2 (AnxA2) is a calcium and lipid-conjugated protein that binds phospholipids and the cytoskeleton in a Ca²⁺-dependent manner, and it participates in various cellular functions, including vesicular trafficking, organization of membrane domains, and virus proliferation. The role of the AnxA2 gene during virus infection has not yet been reported. In this study, we observed that AnxA2 gene expression was up-regulated in BHK-21 cells infected with the virus. Additionally, overexpression of the AnxA2 gene promoted the release of mature virus particles, whereas BEFV replication was remarkably inhibited after reducing AnxA2 gene expression by using the small interfering RNA (siRNA). For viral proteins, overexpression of the Matrix (M) gene promotes the release of mature virus particles. Moreover, the AnxA2 protein interaction with the M protein of BEFV was confirmed by GST pull-down and co-immunoprecipitation assays. Experimental results indicate that the C-terminal domain (268-334 aa) of AxnA2 contributes to this interaction. An additional mechanistic study showed that AnxA2 protein interacts with M protein and mediates the localization of the M protein at the plasma membrane. Furthermore, the absence of the AnxA2-V domain could attenuate the effect of AnxA2 on BEFV replication. These findings can contribute to elucidating the regulation of BEFV replication and may have implications for antiviral strategy development.

Genetically modified rabies virus vector-based bovine ephemeral fever virus vaccine induces protective immune responses against BEFV and RABV in mice

Bovine ephemeral fever (BEF), caused by the bovine ephemeral fever virus (BEFV), is associated with an acute febrile infection in cattle and widespread in tropical and subtropical areas, leading to great economic losses to cattle and milk industry. However, no efficacious BEF vaccine is currently available in China. Herein, we generated a recombinant rabies virus (RABV) expressing BEFV glycoprotein (LBNSE-BG), utilizing a reverse genetics system based on the recombinant rabies virus strain LBNSE. It was found that mice immunized with LBNSE-BG produced robust neutralizing antibodies against both BEFV and RABV, and developed complete protection from lethal RABV challenge. Further studies showed that LBNSE-BG activated more dendritic cells (DCs), B cells and T cells in immunized mice than the parent virus LBNSE. Collectively, these findings demonstrate that the recombinant LBNSE-BG described here has the potential to be developed as a cost-effective and efficacious bivalent vaccine for cattle use in endemic areas of BEF and rabies.

Serosurveillance and Molecular Investigation of Wild Deer in Australia Reveals Seroprevalence of Pestivirus Infection

Since deer were introduced into Australia in the mid-1800s, their wild populations have increased in size and distribution, posing a potential risk to the livestock industry, through their role in pathogen transmission cycles. In comparison to livestock, there are limited data on viral infections in all wildlife, including deer. The aim of this study was to assess blood samples from wild Australian deer for serological evidence of exposure to relevant viral livestock diseases. Blood samples collected across eastern Australia were tested by ELISA to detect antigens and antibodies against Pestivirus and antibodies against bovine herpesvirus 1. A subset of samples was also assessed by RT-PCR for Pestivirus, Simbu serogroup, epizootic hemorrhagic disease virus and bovine ephemeral fever virus. Our findings demonstrated a very low seroprevalence (3%) for ruminant Pestivirus, and none of the other viruses tested were detected. These results suggest that wild deer may currently be an incidental spill-over host (rather than a reservoir host) for Pestivirus. However, deer could be a future source of viral infections for domestic animals in Australia. Further investigations are needed to monitor pathogen activity and quantify possible future infectious disease impacts of wild deer on the Australian livestock industry.