#India - #Equine #influenza #H3N8 virus (Inf. with) - Immediate notification

 Domestic equidae species in Uttarakhand State.

Source: WOAH, https://wahis.woah.org/#/in-review/6441

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Multiple introductions of #equine #influenza virus into the #UK resulted in widespread #outbreaks and #lineage #replacement

Abstract

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.

Author summary

Influenza causes significant disease burden in animals, including wild birds, sea lions, pigs, horses, dogs, and more recently, cows. Outbreaks and epizootics of influenza in agricultural species are a threat to food security and the economy whereas in wild animals they could affect biodiversity and conservation efforts. Given the zoonotic nature of influenza viruses and the high levels of contact between domestic animals and humans, animal influenza is also a public health concern. Here, we combined geographical, epidemiological, and virus sequence data to determine key factors that led to one of the largest epizootics of equine influenza in the United Kingdom in decades. We show that an American equine influenza virus lineage was introduced into Europe and replaced the virus lineage that had been circulating in the United Kingdom for nearly 20 years. We also analysed a global dataset of virus genomes and propose a model of equine influenza virus intercontinental migration, in which USA is the main source of viruses to other countries. Our results provide important information concerning the basic principles of influenza virus circulation in animal populations. This is central to devise effective measures of disease control that would increase animal health while reducing zoonotic risk.

Source: PLoS Pathogens, https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013227

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#Japan - Equine #influenza virus (Inf. with) - Immediate notification

 <Outbreaks 1-3> In early April, Livestock Hygiene Service Centres (LHSCs) in Kumamoto Prefecture received notifications from farmers with animals presenting clinical signs and collected samples. On 8 April, the LHSCs confirmed positive for Equine Influenza by RT-PCR. Genotyping is currently underway.

Source: WOAH, https://wahis.woah.org/#/in-review/6420

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#Equine #Influenza: #Epidemiology, #Pathogenesis, and Strategies for #Prevention and Control

Abstract

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.

Source: Viruses, https://www.mdpi.com/1999-4915/17/3/302

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Use of #equine #H3N8 #hemagglutinin as a broadly protective #influenza #vaccine immunogen

Abstract

Development of an efficacious universal influenza vaccines remains a long-sought goal. Current vaccines have shortfalls such as mid/low efficacy and needing yearly strain revisions to account for viral drift/shift. Horses undergo bi-annual vaccines for the H3N8 equine influenza virus, and surveillance of sera from vaccinees demonstrated very broad reactivity and neutralization to many influenza strains. Subsequently, vaccinating mice using the equine A/Kentucky/1/1991 strain or recombinant hemagglutinin (HA) induced similar broadly reactive and neutralizing antibodies to seasonal and high pathogenicity avian influenza strains. Challenge of vaccinated mice protected from lethal virus challenges across H1N1 and H3N2 strains. This protection correlated with neutralizing antibodies to the HA head, esterase, and stem regions. Vaccinated ferrets were also protected after challenge with H1N1 influenza A/07/2009 virus using whole viral or HA. These data suggest that equine H3N8 induces broad protection against multiple influenzas using a unique antigen that diverges from other universal vaccine approaches.

Source: npj Vaccines, https://www.nature.com/articles/s41541-024-01037-1

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#Sudan - #Equine #influenza virus (Inf. with) - Immediate notification

Virus untyped. Unspecified domestic equidae species in South Darfur.

Source: WOAH, https://wahis.woah.org/#/in-review/6097

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