Infection with Streptococcus equi subspecies equi (S. equi) is characterised by acute disease, with about 10% of infected animals remaining persistently infected. Clinically, infection with S. equi cannot readily be distinguished from infection caused by other respiratory pathogens, including Streptococcus equi subspecies zooepidemicus (S. zooepidemicus), equine influenza virus, and equine herpes virus. Screening protocols, with appropriate quarantining facilities, are important to detect horses infected with S. equi and avoid strangles outbreaks. Virulent strains of S. zooepidemicus can also cause strangles-like presentations. To evaluate the effectiveness of the screening process implemented at a UK welfare centre to prevent the introduction of strangles and strangles-like presentations. Retrospective cross-sectional study. Clinical records of 626 equids admitted to a UK welfare centre between 2017 and 2021 and from horses that developed respiratory signs after admission were reviewed. The screening protocol, which included a clinical examination, paired serology samples (iELISA) taken 6 weeks apart, and bilateral guttural pouch endoscopy to identify abnormalities such as chondroids with lavage for qPCR and culture analysis for S. equi (and often S. zooepidemicus) was implemented during this time. There were 34 screening-positive equids. Of these, 24 (3.8%) were qPCR-positive for S. equi, 8 were qPCR/culture positive for S. zooepidemicus, and 2 were qPCR/culture negative but had chondroids. Bilateral guttural pouch endoscopy, with qPCR analysis of lavage material, was an effective method of screening equids. There were no cases of strangles or strangles-like presentations within the main herds after screening and admission of new horses. Variation in the level of detail of clinical records. The screening process resulted in the identification of screening-positive equids and maintained a strangles-free herd. Further research is required to elucidate the significance of S. zooepidemicus infection in the guttural pouch.

Equine influenza virus (EIV) H3N8 is a highly contagious respiratory pathogen that poses significant health and economic risks to equids globally. In southeastern Nigeria where equids are sold and slaughtered, limited data exist on EIV epidemiology and circulating lineages. To address this gap, an active surveillance was conducted between January 2022 and October 2023. A total of 400 nasal swabs were collected from horses and donkeys at slaughterhouses and animal markets. The swabs were screened for equine influenza virus (EIV) using quantitative Reverse-Transcription Polymerase Chain Reaction (RT-qPCR), and positive samples underwent whole-genome sequencing. A spatiotemporal Bayesian phylogeographic analysis was performed. Amino acid comparisons were carried out against the World Organization for Animal Health (WOAH) recommended Florida clade-1 (Fc-1) vaccine strains (accession numbers GU447312, DQ124192) and mutations were mapped onto 3D H3 hemagglutinin structure with protein data bank 4UO0 using PyMOL. Two samples (0.5%) from non clinical signs and deceased donkeys tested positive for the H3N8 virus. A spatiotemporal Bayesian phylogeographic analysis, which included sequences from outbreaks in Africa between 2018 and 2023, revealed multiple introductions of the virus into Africa. The introductions of Fc-1 lineage into Africa may have originated from Argentina (2018/2019) and the UK (2021), while Florida clade-2 seems to have originated from Ireland (2019). The 2022 H3N8 strains identified in this study may be a result of persistence from the 2018/2019 epizootic in northern Nigeria. Additionally, we discovered previously unreported hemagglutinin substitutions compared to the WOAH recommended Fc-1 vaccine strain, along with novel changes adjacent to antigenic sites and four distinct glycosylation profiles in the virus, which underscores their potential epidemiological significance. Our findings revealed multiple introductions of EIV probably from South America and Western Europe, rapid virus evolution, and significant transboundary spread facilitated by livestock trade, particularly involving donkeys and subclinical infections in the transmission of the virus. These results underscore the persistence and evolution of EIV H3N8 (Fc-1) in Nigeria and emphasize the need for improved genomic surveillance, control measures, and vaccination strategies against EIV in Africa. Additionally, regulating transboundary livestock trade is essential to mitigate the risk of future outbreaks.

Integration of empirical network data and agent-based modelling to examine the risk of equine influenza infection in equine athletes in Ontario, Canada.

Background Equine influenza virus (EIV) can cause acute infections and outbreaks of epidemics in horses and donkeys. It is one of the most economically impactful pathogens in equine respiratory diseases globally, resulting in substantial financial losses within the farming industry. Utilizing targeted anti-viral drugs is an effective strategy. Purpose The present study analyzes the potential of herbal medicines for the treatment of equine influenza (EI) based on network pharmacology, molecular docking techniques, and in vitro anti-viral studies. Materials and Methods The construction of a “traditional Chinese medicine (TCM) component–target–disease” network was performed using Cytoscape 3.9.0. The protein–protein interaction (PPI) network is performed through the STRING system. Bioconductor software was employed to conduct gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) functional enrichment analyses of biological processes (BPs). Molecular docking techniques revealed the degree of binding of core components to key target genes. Characterization of the anti-EI effect of TCM by cytotoxicity and in vitro studies. Results Consequently, five core TCMs were screened, which had 79 core targets related to EI. PPI network analysis highlighted 10 significant targets. Molecular docking results analysis revealed binding interactions between the main core component, kaempferol, and the targets prostaglandin-endoperoxide synthase 2 (PTGS2), matrix metalloproteinase-9 (MMP9), and estimated glomerular filtration rate (EGFR), with binding energies of −9.1, −8.3, and −8.0 (kcal/mol), respectively. In vitro studies have demonstrated that the inhibitory effect of kaempferol on EI is mainly in the initial phase. Conclusion Through network pharmacology, molecular docking, and in vitro experiments, kaempferol was demonstrated to combat EI through key targets of PTGS2, MMP9, EGFR, AKT, tumor necrosis factor (TNF), and IL-6. This study provides a basis for treating EI with herbal medicine and for later drug development. Future research should integrate network pharmacology with clinical applications, focusing on large-scale clinical trials to evaluate the efficacy and safety of TCM in influenza treatment, thereby enhancing its potential role in treating the disease.

Genetic and serological analyses of equine influenza viruses isolated in Kumamoto and Hokkaido, Japan in 2025.

Equine influenza (EI) is a highly contagious respiratory disease that poses significant economic and health challenges to the global equine industry. Current diagnostic methods, such as hemagglutination inhibition (HI), are accurate but complex and impractical for widespread use, especially in regions like China where commercial kits are unavailable. This study developed a competitive ELISA (cELISA) for detecting EI virus antibodies, offering a simpler, faster, and more cost-effective alternative. The assay demonstrated higher concordance with HI than existing commercial kits and effectively monitored antibody responses in vaccinated horses. Additionally, it enabled the first large-scale serological survey of EI in China, providing critical insights into the virus's prevalence. This advancement supports timely disease detection and control, benefiting veterinary practices and the equine industry worldwide.

The Canine Influenza Virus (CIV) is a causative agent of flu in dogs and belongs to the highly mutable Type A influenza virus group, which also infects various animals and humans. Despite ongoing efforts to control it, genetic variations in Type A influenza viruses persist. This paper aims to provide practitioners, pet owners, academics, and policymakers with a concise overview of CIV to support early prevention, treatment, and containment strategies, particularly in Indonesia. The data presented in this paper are derived from scientific reports on canine flu cases caused by Type A influenza subtypes H3N8 and H3N2. The first reported case of H3N8 CIV infection occurred in the early 2000s in the United States, primarily affecting Greyhound dogs. This strain originated from an equine influenza outbreak in America. Meanwhile, the H3N2 subtype, which later emerged in dogs in the U.S., shares genetic similarities with strains isolated in China and South Korea, suggesting intercontinental transmission. Clinical signs of CIV infection are typically mild and resemble general flu symptoms but may worsen with secondary infections. As a zoonotic virus, CIV poses a potential threat to public health if left unaddressed. Thus, further investigation into canine influenza cases in Indonesia is essential, along with public education on vaccination and stricter regulations on the movement of animals from affected countries.

Despite routine vaccination, equine influenza outbreaks occur due to disparities of virus strains between vaccine and field, and immunity gaps between vaccinations. To evaluate whether a combination of adjuvants can enhance immune responses to equine influenza virus (EIV) vaccines. In vivo experimental study. Eight mixed-breed horses were immunised intramuscularly with a recombinant canarypox-based EIV vaccine, either alone or in combination with monophosphoryl lipid A (MPL) and polyinosinic-polycytidylic acid (poly I:C). A single vaccine dose was administered, and serum samples were collected before immunisation and at 2, 8, and 24 weeks post-immunisation to assess the humoral immune response. Peripheral blood mononuclear cells (PBMCs) were isolated to evaluate immunomodulatory cytokine expression and characterise recall cellular immune responses. Additionally, bone marrow and lymph node cells were analysed to assess memory cell responses. The combination of MPL and poly I:C significantly enhanced serum IgG antibody concentrations and haemagglutination inhibition (HI) titres against H3N8 A/equine/Kyonggi/SA01/2011 (Florida sub-lineage clade 1) and maintained these for up to 24 weeks post-immunisation. This combination led to increased cytokine mRNA expression and interferon-gamma (IFN-γ) responses in PBMCs. Enhanced memory B cell responses were also observed in the bone marrow and lymph nodes at 8 weeks post-immunisation. MPL and poly I:C induced higher frequencies of CD4+ and CD8+ T cells following in vitro restimulation with H3N8 EIV. A viral challenge experiment was not included. The use of MPL and poly I:C as adjuvants in EIV vaccines significantly improved immune responses by enhancing humoral immunity, memory cell responses, and antigen-specific cellular immunity.

Tracing the 2021 equine influenza Outbreak: First characterization and phylogeographic analysis of H3N8 Florida clade 1 virus in Tunisia.

Equine influenza is a highly contagious disease caused by the equine influenza virus (EIV). The occurrence of EIV outbreaks in America is associated with low levels of vaccination coverage. In Colombia, no seroprevalence evaluation has been carried out to estimate the distribution of the virus within the country. Our aim was to perform a sero-epidemiological survey of equine influenza infections and to identify associated risk factors in horses from four departments of Colombia. Serological testing was carried out by using an ELISA for the detection of IgG antibodies against the influenza A virus. The evaluation of epidemiological variables, clinical manifestations, and vaccination history was carried out through the application of a data collection instrument. Among the 385 horses analyzed, 27% of the samples tested positive, with a higher prevalence in Study 1 from horses with respiratory symptoms (40.4%) than in Study 2 from horses without clinical signs (16.1%). Only horses housed in stables had higher odds of testing positive. The study also revealed that unvaccinated horses were 68% less likely to test positive than vaccinated horses were. This research highlights a significant gap in vaccination coverage and the presence of antibodies even in asymptomatic horses. Management factors such as activity type and housing should be considered when strategies for EIV prevention are developed.

Reverse genetics (RG) technology is useful for quickly updating influenza vaccine strains. A high-yield backbone (i.e., six segments other than hemagglutinin and neuraminidase) derived from A/Puerto Rico/8/1934 (PR8) has been developed to improve the growth of avian and human influenza viruses. However, for equine influenza virus (EIV), an EIV-derived backbone may have better growth properties due to more-natural segment combinations. We compared the growth properties in eggs between the PR8 backbone and an EIV backbone from A/equine/Ibaraki/1/2007, a vaccine strain in Japan. The results showed that the PR8 backbone was propagated more efficiently and is therefore more suitable for EIV vaccine production.

Equine influenza antigen-based particle vaccine protects mice against homologous and heterosubtypic viral challenges.

This study investigated the equine upper respiratory tract microbiome (URTM) across Kazakhstan, aiming to identify relationships between microbiome composition and equine influenza A virus presence. URTM samples from 15 Kazakh horses (Zhabe andAdai types, age 3-8 years) in Pavlodar, Zhetysu, and Mangistau regions were analyzed using microbiological and genetic techniques. Serological analysis for equine influenza was performed on blood serum from 50 horses acrossZhambyl, Pavlodar, Zhetysu, and Mangistau regions. The findings demonstrate an influence of environmental factors on the URTM composition, overshadowing the impact of disease status. Microbial community clustering was primarily driven by environment, encompassing both content and geographical location, indicating a strong environmental shaping of the URTM. At the genus level, Nicoletella, Bacillus, Moraxella, Klebsiella, Planococcus, Lactobacillus, andPlannomicrobiumwere most abundant (>0.1%). Eleven phyla were identified, with Proteobacteria (43.85%), Firmicutes(16.82%), Actinobacteria (21.63%), and Bacteroidetes(13.24%) comprising >95% of the total abundance. Serological analysis confirmed equine influenza virus circulation in the studied regions. These findings highlight the complex structure of the equine URTM, regional variations in influenza prevalence, and the dominant role of environmental factors. Further research is needed to explore the influence of specific microbial taxa on immune responses and respiratory disease development. An integrated approach is critical for effective control of equine respiratory diseases

Equine Infectious Anemia Virus (EIAV) poses significant diagnostic challenges due to its genetic variability and the limitations of conventional nucleic acid detection methods. This study developed an antigen-capture, enzyme-linked immunosorbent assay (AC-ELISA) for the detection and quantification of the EIAV capsid protein p26. The assay utilized a monoclonal antibody (1G11) specific to the p26 protein as the capture antibody and a polyclonal antibody as the detection antibody, forming a highly specific and sensitive detection system. Under optimized conditions, the detection limit of the AC-ELISA was 1.95 ng/mL, with a good linear relationship observed between 1.95 ng/mL and 60.5 ng/mL of p26 protein. Additionally, the AC-ELISA effectively distinguished EIAV from other equine viruses, including equine herpesvirus 1 (EHV-1), equine arteritis virus (EAV), and equine influenza virus (EIV), without cross-reactivity. Importantly, the AC-ELISA demonstrated the ability to detect multiple EIAV strains, including virulent strains, attenuated strains, and strains from other countries, highlighting its broad applicability across diverse EIAV isolates. Compared to western blot and reverse transcriptase assays, the AC-ELISA exhibited higher sensitivity and strong correlation in quantifying the EIAV p26 protein. The assay is simple, rapid, and cost-effective, making it suitable for both laboratory research and clinical applications. It provides a powerful tool for EIAV detection and quantification, supporting future vaccine development and clinical trials.

Equine influenza virus (EIV) is a highly contagious and major respiratory viral disease of horses and donkeys causing severe economic impact to equine industry globally. Data on the epidemiology and lineages of EIV in circulation in Nigeria is limited. To shed more light on these, a cross-sectional survey was conducted in slaughter houses and animal markets in Ebonyi state, South East Nigeria from January 2022 to July 2023. Four hundred (400) sera samples were collected and screened for antibodies against nucleoprotein (NP) of influenza A virus using Multispecies competitive enzyme-linked immunosorbent assay (ELISA) influenza A kit, (IDEXX, France). Thirty (30) subset of positive sera samples for influenza A virus antibodies by ELISA were further screened and subtyped using HI assay. The results showed that antibodies against influenza A virus nucleoprotein were detected in 7.5% (30 of 400) of horses and donkeys examined by Multispecies competitive ELISA influenza A kit. The subtyping of the ELISA positive sera revealed EI H3 (n=2) subtypes. The presence of EI as reported in this study could be a present or a past EI infection as there was no evidence of vaccination as reported in this study. The role of transboundary trade in the transmission of EIV cannot be over emphasized, therefore proper biosafety, quarantine of imported horses and donkeys, vaccination and control of illegal animal trade should be strengthened across the country.

Equine influenza (EI) is a highly contagious respiratory disease that affects horses and has significant economic consequences for the global equine industry. It has a worldwide distribution and cases must be reported to the World Organisation for Animal Health (WOAH). Understanding the epidemiology of the disease, risk factors and enabling conditions is important to prevent the introduction of equine influenza virus.

Monitoring infectious diseases is essential for safeguarding equine health and ensuring the sustainability of the horse industry. In 2019, the Royal Veterinary Association of the Netherlands (KNMvD) and Royal GD (GD Animal Health) launched SEIN (Surveillance of Equine Infectious diseases in the Netherlands), a voluntary surveillance system for laboratory-confirmed outbreaks of equid alphaherpesvirus 1 (EHV-1), equid alphaherpesvirus 4 (EHV-4), equine influenza virus (EIV), and Streptococcus equi subsp. equi. This retrospective study analyzed 364 confirmed outbreaks reported through SEIN between June 2019 and April 2023. S. equi was the most commonly reported pathogen overall (64%). Among outbreaks involving respiratory disease, S. equi accounted for 74% of cases, followed by EHV-4 (16%), EIV (6%), and EHV-1 (4%). The geographical distribution of outbreaks covered 80 of the 90 postal code regions (89%), and approximately half of all participating practices generated at least 1 alert. Vaccination data revealed low coverage against EHV-1/4, EIV, and S. equi among both affected horses and premises. Clinical signs overlapped between pathogens, but some were more pathogen-specific, e.g., coughing in EIV, and abscessation in S. equi. The SEIN system provided spatiotemporal information on confirmed outbreaks. These results underscore the importance of quick diagnostics and structured surveillance systems in guiding prevention strategies.

Influenza A viruses (IAVs) are prime examples of emerging viruses in humans and animals. IAV circulation in domestic animals poses a pandemic risk as it provides new opportunities for zoonotic infections. The recent emergence of H5N1 IAV in cows and subsequent spread over multiple states within the USA, together with reports of spillover infections in humans, cats and mice highlight this issue. The horse is a domestic animal in which an avian-origin IAV lineage has been circulating for >60 years. In 2018/19, a Florida Clade 1 (FC1) virus triggered one of the largest epizootics recorded in the UK, which led to the replacement of the Equine Influenza Virus (EIV) Florida Clade 2 (FC2) lineage that had been circulating in the country since 2003. We integrated geographical, epidemiological, and virus genetic data to determine the virological and ecological factors leading to this epizootic. By combining newly-sequenced EIV complete genomes derived from UK outbreaks with existing genomic and epidemiological information, we reconstructed the nationwide viral spread and analysed the global evolution of EIV. We show that there was a single EIV FC1 introduction from the USA into Europe, and multiple independent virus introductions from Europe to the UK. At the UK level, three English regions (East, West Midlands, and North-West) were the main sources of virus during the epizootic, and the number of affected premises together with the number of horses in the local area were found as key predictors of viral spread within the country. At the global level, phylogeographic analysis evidenced a source-sink model for intercontinental EIV migration, with a source population evolving in the USA and directly or indirectly seeding viral lineages into sink populations in other continents. Our results provide insight on the underlying factors that influence IAV spread in domestic animals.

Donkeys are routinely vaccinated with protocols developed for horses, yet species-specific data on their immune responses are limited. We hypothesized that donkeys exhibit robust T-cell-mediated immunity and regulatory adaptation after vaccination, comparable to horses. Thirty-six healthy, seronegative donkeys (34 mares, 2 stallions), aged 0.5-23 years (median 8 years), from two farms with similar housing and management conditions. Prospective study. Animals were selected based on clinical health assessment and confirmed seronegativity for tetanus and equine influenza. All received a multivalent vaccine containing tetanus toxoid and equine influenza antigens. Blood samples were collected at baseline, 1 month, and 2 months after vaccination. Flow cytometry assessed CD4+, CD8+, and CD4 + FoxP3+ T cells (primary outcomes), and monocyte subsets and B lymphocytes (PanB/CD21+) with intracellular IL-10, IL-17, and Ki67 (secondary outcomes). ANOVA with Bonferroni correction (p < 0.05) was used for statistical analysis. CD4+ T cells increased from 25.1% ± 1.4% to 37.3% ± 0.7% at month 1, CD8+ from 20.6% ± 1.5% to 32.2% ± 0.9% at month 2 (p < 0.001). CD4 + FoxP3+ peaked at 11.7% ± 0.6% at month 1 (baseline 6.8% ± 0.8%), then returned to baseline. CD14 + MHCII+ and CD14 + MHCII- monocytes declined; CD14 - MHCII+ increased (p < 0.01). PanB/CD21+ cells decreased from 41.5% ± 1.8% to 29.0% ± 1.0%, with significant reductions in IL-10+, IL-17+, and Ki67+ subsets (p < 0.001). Donkeys exhibit strong T-cell and regulatory immune responses after vaccination, supporting the clinical relevance of applying equine vaccination protocols to donkeys.

Since December 2019, the COVID-19pandemic has spread globally, prompting governments in many countries to implement lockdowns to control the transmission of the virus. Outbreaks of emerging infectious diseases, such as COVID-19, and the associated government lockdowns may have significant negative impacts on mental health. A comprehensive review of the available evidence on this topic can provide useful information for policymakers. This review aimed toassess the effects of government lockdowns on the mental health of the general population during emerging infectious disease outbreaks. On April 11, 2022, we conducted a systematic search of CENTRAL, MEDLINE, PsycINFOOvid, and two clinical trial registries, supplemented by reference checking and citation searching. We included non-randomized studies of interventions (NRSIs) involving adults and adolescents, regardless of comorbidities, that examined the effects of government-imposed lockdowns compared to no lockdown during outbreaks of emerging infectious diseases, including SARS, MERS, COVID-19, H1N1, equine influenza, avian influenza, and Ebola virus disease. Critical outcomes assessed were depressive symptom severity and suicide, while important outcomes included anxiety symptom severity, post-traumatic stress disorder (PTSD) symptom severity, insomnia symptom severity, and substance use. We used the ROBINS-I tool to assess the risk of bias and conducted a meta-analysis using a random-effects model. The certainty of evidence was evaluated using theGRADEapproach. We included 42 NRSIs, all conducted during the COVID-19 pandemic. Of the 27 studies reporting depressive symptoms, we pooled effect sizes from eight studies. The findings suggest that government lockdowns may have little to no effect on depressive symptom severity within the 12-month follow-up; however, the evidence was very uncertain (standardized mean difference (SMD) 0.00, 95% CI -0.08 to 0.09; I2 = 70%; 11,278 participants). Two studies reported on suicide outcomes, but both had an overall critical risk of bias due to confounding; therefore, we did not synthesize results and judged the evidence as very low certainty. For anxiety symptom severity, we pooled data from five of 20 studies and found that government lockdowns may have little to no effect within the 12-month follow-up (SMD 0.08, 95% CI -0.10 to 0.26; I2 = 91%; 11,006 participants). Regarding PTSD symptom severity, pooled data from one of two studies suggested that government lockdowns may increase the symptom severity within the 12-month follow-up (MD0.18, 95% CI 0.08-0.28; 1,754 participants). We pooled data from two of eight studies on insomnia symptom severity and found that government lockdowns may increase the symptom severity within the 12-month follow-up (MD 1.28, 95% CI 0.62-1.94; I2 = 91%; 5,142 participants). In terms of alcohol use, data pooled from five of nine studies on alcohol use showed that government lockdowns may have little to no effect on alcohol consumption within the 12-month follow-up (SMD 0.03, 95% CI -0.05 to 0.11; I2 = 66%; 8,261 participants). Overall, the evidence regarding all important outcomes was of very low certainty. At present, the impact of government lockdowns during emerging infectious disease outbreaks on mental health in the general population remains very uncertain. Future research should prioritize well-designed studies to better assess the mental health effects of lockdown measures during novel outbreaks.