Search Results (81)

H9N2 avian influenza virus (AIV) is widely prevalent in poultry in China. To understand the genetic characteristics and evolution of H9N2 AIVs in Guangxi, southern China, the complete genomes of H9N2 AIVs from 1999–2023 were systematically analysed. Maximum likelihood (ML) trees indicated that H9N2 AIV gene sublineage diversity contributed to genotype diversity, yielding 17 genotypes (G1–G17). Since 2010, genotype G14 (also known as genotype S or G57) has become predominant in poultry in Guangxi. Phylogenetic analysis in the HA has resulted in the distancing of recent Guangxi isolates from the vaccine strains. This study also revealed that the genotypes of H9N2 AIVs infecting swine, equines and canines in Guangxi were consistent with those found in avian species at the same time, highlighting the capacity of H9N2 AIVs to be transmitted across species. The antigenic residues in the HA head region and NA protein of the Guangxi isolates from 2020–2023 changed significantly compared to the vaccine strains, suggesting possible antigenic drift in these viruses. Amino acid analysis of the HA protein revealed that 84.9% (73/86) of H9N2 AIV isolates from Guangxi, including those from live poultry markets, preferentially bound to α-2,6 sialic acid receptors. Considerable attention should be given to cross-species transmission of H9N2 AIV in the region. On the basis of these findings, strengthening the monitoring of H9N2 AIV in poultry in Guangxi is essential. Full article

Influenza D virus (IDV), belonging to the Orthomyxoviridae family, was first discovered in 2011 in pigs. Surveys in humans and animals have been carried out to decipher IDV ecology. In this seroepidemiological study, we investigated the circulation of IDV lineages across Italy in livestock and wildlife animals. A total of 1038 animal serum samples (from 246 bovines, 249 swine, 98 equines, and 445 wild boars) were tested using hemagglutination inhibition and virus neutralization assays. The results confirm bovines as the primary reservoir for IDV, with high seroprevalence for both D/660 (87%) and D/OK (80%) strains. Swine and equines demonstrated limited exposure, suggesting they are infrequent spillover hosts. Notably, wild boars showed high seroprevalence, especially for the D/660 lineage (80%), indicating their potential role in a wildlife transmission cycle. Continuous surveillance in both livestock and wildlife is essential to monitor the spread and evolution of IDV. Full article

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. Full article

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. Full article

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. Full article

In recent years, the use of non-invasive host and environmental samples for the detection and monitoring of equine respiratory pathogens has shown promise and a high overall agreement with the gold standard of nasal secretions. The present study looked at comparing nose wipes, stall sponges, and air samples with nasal swabs collected from 27 horses involved in an equine influenza (EI) outbreak. The outbreak involved 5 clinical, 6 subclinical, and 16 uninfected horses. Samples sets were collected at the onset of the index case and retested every 2–3 days thereafter until all horses tested qPCR-negative for EI virus (EIV). Nose wipes and stall sponges identified EIV in all clinical cases, and air samples identified EIV in 4/5 clinical horses. The overall agreement with all nasal swabs collected from clinical cases was 89% for nose wipes, 78% for stall sponges, and 44% for air samples. Due to the shorter shedding time in subclinical cases, nose wipes and stall sponges detected EIV in 5/6 and 4/6 subclinical horses, respectively. Only one single air sample tested qPCR-positive for EIV in a subclinical shedder. When compared to the gold standard of nasal secretions in subclinically infected horses, the overall agreement was 54% for stall sponges, 50% for air samples, and 45% for nose wipes. The collection of non-invasive contact and environmental samples is a promising alternative to nasal swabs for the detection of EIV in clinically and subclinically infected horses. However, they should always be considered as a second-choice sample type to the more accurate nasal swabs and used to test refractory horses or large populations during outbreaks. Further, the pooling of identical or different samples collected from the same horse for the qPCR testing of EIV increases the accuracy of detecting EIV, especially in subclinically infected horses. Full article

Preventing the spread of infectious diseases in horses requires breaking the chain of infection through appropriate prophylaxis. In Poland, where the horse population reached 273,006 in 2023, vaccinations are voluntary and primarily the responsibility of horse owners, with mandatory influenza vaccinations limited to sport horses. This study aimed to evaluate the vaccination status of Polish horses against infectious diseases through a survey of 980 horse owners and an analysis of 123 horse passports from slaughterhouses. Survey participants represented all provinces, predominantly owning warmblood horses (86%), but also 10% coldblood and 4% ponies or unidentified. Nearly half engaged in equestrian competitions. While over 90% of sport and pleasure horses were vaccinated against key diseases such as equine influenza and tetanus, only 2.4% of slaughter horses had similar prophylaxis. Cold-blooded horses were underrepresented in the survey (10.4%) but made up 68.3% of the analyzed slaughterhouse sample. The findings highlight a significant disparity in vaccination practices, primarily influenced by the horse’s intended use, with sport and leisure horses receiving better preventive care than slaughter horses. These results underscore the need for targeted educational efforts and policy interventions to improve the epizootiological status of Poland’s horse population and ensure a more uniform approach to disease prevention. A limitation of this study is the accuracy of vaccination records in horse passports, as some owners may not have them during vaccination, leading to discrepancies. Full article

Equine influenza (EI) is a highly contagious respiratory disease caused by the equine influenza virus (EIV), posing a significant threat to equine populations worldwide. EIV exhibits considerable antigenic variability due to its segmented genome, complicating long-term disease control efforts. Although infections are rarely fatal, EIV’s high transmissibility results in widespread outbreaks, leading to substantial morbidity and considerable economic impacts on veterinary care, quarantine, and equestrian activities. The H3N8 subtype has undergone significant antigenic evolution, resulting in the emergence of distinct lineages, including Eurasian and American, with the Florida sublineage being particularly prevalent. Continuous genetic surveillance and regular updates to vaccine formulations are necessary to address antigenic drift and maintain vaccination efficacy. Additionally, rare cross-species transmissions have raised concerns regarding the zoonotic potential of EIV. This review provides a comprehensive overview of the epidemiology, pathogenesis, and prevention of EI, emphasizing vaccination strategies and addressing the socio-economic consequences of the disease in regions where the equine industry is vital. Full article

To identify measures that mitigate the impact of influenza in Latin America and the Caribbean, we compared the burden and detection capacity in humans and animals after the 2009 pandemic. The incidence rate in people was higher in Chile (23.72 per 100,000 people), but the impact was greater for Guatemala (503.78 disability-adjusted life years per 100,000 people). Brazil, Peru, Argentina, and Mexico built better medical testing, with typing being less frequent in Chile and Argentina, where costs for medical care were higher. The positivity rate among avian and nonhuman mammals was 5.8%, with more cases in Mexico, but constant testing in Chile. H5N1, H5N2, and H7N6 are deadly to poultry, whereas H1N1 is common in swine, and H3N8 in equines. By June 2023, H5N1 had caused severe influenza in two persons and killed millions of birds and hundreds of mammals with aquatic lifestyles. An analysis of the efforts in response to this outbreak revealed that handling of outbreaks in animals needs homogeneity and reinforcement of vaccination. Surveillance in exposed individuals requires articulation of medical and animal health authorities, and the region also demands decentralized typing and networks for genomic characterization. Full article

Influenza A is a zoonotic disease that affects dogs, pigs, horses, poultry, and birds. In this report, a meta-analysis according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) was conducted. Studies of influenza A viruses in dogs providing prevalence or seroprevalence in any location worldwide were included. The results in this study show that the seroprevalence for the H3N8 influenza subtype was 7.96% (95% CI: 2.03–16.8, p < 0.001), for the H3N2 subtype was 7.44% (95% CI: 4.51–10.5, p < 0.001), and for the H1N1 subtype was 3.10% (95% CI: 0.890–6.01, p < 0.001). In the case of the prevalence analysis, a prevalence of 0.395% (95% CI: 0.160–2.44) for the H3N8 subtype. For the H3N2 subtype, a prevalence of 17.8% (95% CI: 6.66–32.6, p < 0.001) was found. No publication bias was observed in the studies evaluating seroprevalence in the H3N2 and H1N1 subtypes. In the H3N8 subtype, Begg’s test indicated publication bias, but Egger’s test showed no bias. It is essential to know the approximate prevalence and seroprevalence worldwide of canine influenza, so this study reports the presence of influenza subtypes in dogs, placing this species as a reservoir for human, swine, equine, and avian influenza A viruses. Full article

A comparative medicine approach, whereby similarities and differences in biology between human and veterinary species are used to enhance understanding for the benefit of both, is highly relevant to the development of viral vaccines. Human and equine influenza share many similarities in pathogenesis and immune responses. The DNA vaccine approach offers potential advantages for responding rapidly and effectively to outbreaks or pandemics in both humans and animals, especially in under-resourced regions. The European and American vaccine regulatory authorities require demonstration of vaccine efficacy in animal models. However, mice, the most widely used model, are not naturally infected with influenza viruses, resulting in different pathobiology. Additionally, mice as a model for DNA vaccine testing appear to overestimate the humoral immune response compared to other mammalian species. In this review, we propose that testing of DNA vaccines against influenza type A viruses (and other shared pathogens) in the horse can provide valuable knowledge for the development of human DNA vaccines. Full article

The quality of equine colostrum is typically defined by refractometry or the concentration of maternal antibodies. However, the activity of other equine colostral bioactive molecules has not yet been investigated. This study analyzed whether the administration of a Saccharomyces cerevisiae fermentation product (SCFP) influences the biological activity of mare colostrum and whether the biological activity of colostrum has a lasting immunomodulating effect for foals. A total of fourteen pregnant mares received 20 g/day of a SCFP for a period of twelve weeks prior to the calculated date of birth (SCFP-group). Twelve pregnant mares without supplementation served as controls (CON). Colostral Brix values were determined within three hours after parturition. The concentration of IgG in blood sera and colostrum samples was determined with an ELISA. The biological activity was determined in a cell growth assay with a porcine epithelial cell line (IPEC-J2). Mares (at three weeks before the calculated date of birth) and foals (at the age of 5–8 months) received a parenteral active vaccination against influenza and tetanus. The administration of SCFP did not alter the mare’s serum and colostrum IgG concentrations and did not exert a significant influence on the mares’ early response to the vaccination. Growth and diarrhea episodes were comparable between foals of supplemented mares (SCFP) and foals of mares without supplementation (CON). Colostrum samples from SCFP-supplemented mares exhibited heightened biological activity. While SFCP and CON foals did not differ in their early response to vaccination, the vaccination-induced alterations in circulating neutrophilic granulocyte numbers were significantly correlated with the biological colostrum activity. These findings suggest that the supplementation of mares in late gestation with SCFP can enhance the biological activity of colostrum, which subsequently influences the innate immune responses of their offspring in later life. Full article

The prevalence and impact of Getah virus (GETV) are significant concerns in China. GETV can infect a wide range of animals, including horses, pigs, sheep, cattle, birds, and humans, resulting in substantial losses in the livestock and agricultural industries. GETV infection can cause the development of ulcers and inflammation in the mouth and gums of horses, which result in pain and discomfort and lead to symptoms such as reduced appetite, drooling, and difficulty chewing. As a result, there is a pressing need for efficient and rapid disease diagnosis methods. However, the currently available diagnostic methods have limitations in terms of operational time, equipment, and the experience of the individuals using them. In this study, a rapid, specific, and sensitive detection method was developed using a colloidal gold-based immunochromatographic strip (ICS) for the detection of antibodies against GETV in horses. To prepare the ICS, the antigen domain of the E2 glycoprotein of GETV was expressed using the Escherichia coli expression system after analysis with DNAstar v7.1 software. The nitrocellulose membrane was coated with rE2 protein or SPA to form the test line and control line, respectively. After optimizing the reaction conditions, the sensitivity, specificity, and repeatability of the strip were verified. The results showed that the test strip had a detection limit of up to 1:320 dilutions for GETV-positive serum, with no cross-reactivity observed with other equine-susceptible pathogens such as equine arteritis virus (EAV), equine herpesvirus-1 (EHV-I), equine infectious anemia virus (EIAV), equine influenza virus (EIV), African horse sickness virus (AHSV), and Japanese encephalitis virus (JEV). Furthermore, the ICS exhibited a concordance rate of 94.0% when testing 182 clinical serum samples compared to the virus neutralization test. Overall, this ICS diagnosis method will be an effective tool for the rapid detection of GETV in the field. Full article

Equine influenza is a viral disease caused by the equine influenza virus (EIV), and according to the WOAH, it is mandatory to report these infections. In Latin America and Colombia, EIV risk factors have not been analyzed. The objective of this research is to perform an epidemiological and molecular analysis of the EIV in horses with respiratory symptoms from 2020 to 2023 in Colombia. Molecular EIV detection was performed using RT–qPCR and nanopore sequencing. A risk analysis was also performed via the GEE method. A total of 188 equines with EIV respiratory symptoms were recruited. The positivity rate was 33.5%. The descriptive analysis showed that only 12.8% of the horses were vaccinated, and measures such as the quarantine and isolation of symptomatic animals accounted for 91.5% and 88.8%, respectively. The variables associated with the EIV were the non-isolation of positive individuals (OR = 8.16, 95% CI (1.52–43.67), p = 0.014) and sharing space with poultry (OR = 2.16, 95% CI (1.09–4.26), p = 0.027). In conclusion, this is the first EIV investigation in symptomatic horses in Colombia, highlighting the presence of the virus in the country and the need to improve preventive and control measures. Full article

Background: Equine influenza (EI) is a highly contagious viral disease of equids characterized by pyrexia and respiratory signs. Like other influenza A viruses, antigenic drift or shift could lead to a vaccine-induced immunity breakdown if vaccine strains are not updated. The aim of this study was to genetically characterize EIV strains circulating in Italy, detected in PCR-positive samples collected from suspected cases, especially in the absence of formal active surveillance. Methods: Between February and April 2019, blood samples and nasal swabs collected from each of the 20 symptomatic horses from North and Central Italy were submitted to the National Reference Centre for Equine Diseases in Italy to confirm preliminary analysis performed by other laboratories. Results: None of the sera analysed using haemagglutination inhibition and single radial haemolysis presented a predominant serological reactivity pattern for any antigen employed. All nasal swabs were positive with IAV RRT-PCR. Only one strain, isolated in an embryonated chicken egg from a sample collected from a horse of a stable located in Brescia, Lombardy, was identified as H3N8 Florida lineage clade 1 (FC1). In the constructed phylogenetic trees, this strain is located within the FC1, together with the virus isolated in France in 2018 (MK501761). Conclusions: This study reports the first detection of H3N8 FC1 in Italy, highlighting the importance of monitoring circulating EIV strains to verify the vaccine composition appropriateness for maximum efficacy. Full article