Air sampling for flu detection

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 Air sampling may provide a safe and effective method for detecting horses infected with equine influenza virus (EIV), according to new research from Japan.

EIV, a highly contagious respiratory disease in horses, spreads through aerosolised droplets, direct contact, and contaminated surfaces (“fomites”). Traditionally, confirming EIV infection requires nasopharyngeal swabs, which can be invasive and challenging, especially for untrained or aggressive horses.

 

A study conducted by researchers at the Equine Research Institute, Japan Racing Association, in Shimotsuke, Tochigi, Japan, has demonstrated that EIV can be recovered directly from the air surrounding infected horses. The research, led by Manabu Nemoto and colleagues and published in Veterinary Microbiology, involved experiments with two horses intentionally infected with EIV and housed in individual stalls.

 

Air samples were collected daily for 13 days post-inoculation using an air sampler. The findings showed that EIV RNA was detected in 26 out of 28 air samples using real-time RT-PCR and in 23 samples using a rapid molecular test kit. Significantly, viral RNA was detected in the air before the horses displayed clinical symptoms, emphasising the potential of air sampling for early detection.

 

The research team highlighted that air sampling is a non-invasive and safe alternative to traditional methods, avoiding the risks associated with swab collection. Additionally, the combination of air sampling with rapid molecular diagnostic kits, which can identify viral RNA in under 30 minutes, offers a practical and efficient approach for monitoring and controlling EIV outbreaks.

 

They suggest that this method could be particularly beneficial in quarantine facilities and other high-risk settings where early detection and containment of EIV are essential.

 

For more details, see:

 

Manabu Nemoto, Nanako Kawanishi, Yoshinori Kambayashi, Hiroshi Bannai, Takashi Yamanaka, Koji Tsujimura,

Detection of equine influenza virus gene in the air around infected horses,

Veterinary Microbiology, (2025), Vol 302, 110388,

 

https://doi.org/10.1016/j.vetmic.2025.110388

Horses in Asia Found Infected with H5N1 Avian Influenza

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A recent study has revealed that horses in Asia have been infected with H5N1 avian influenza,
with these infections occurring undetected.  

The research, led by Professor Pablo Murcia from the MRC-University of Glasgow Centre for Virus Research, in collaboration with an international team of scientists from the US and Mongolia, involved antibody testing on horse herds in Mongolia.  The findings, published in Emerging Infectious Diseases, reveal asymptomatic infections in Mongolian horse herds.

 

The researchers tested horse herds in two distinct Mongolian regions: a wetland area with a high population of wild birds and a dry area with low bird density. The results showed higher exposure rates in the wetland region. Importantly, there were no reports of previous respiratory disease outbreaks among the horses, suggesting that the infections were acquired asymptomatically.

 

These findings confirm that avian influenza can spread to other species, including horses. While equine influenza is typically caused by the H3N8 subtype, the detection of H5N1 highlights the potential for avian influenza to infect horses.

The study raises concerns about cross-species transmission, particularly in agricultural environments where horses may be exposed to infected livestock. Since March 2023, the rapid spread of H5N1 in US dairy cattle has amplified the risk of horses contracting avian influenza.

Coinfection with H5N1 and equine influenza (H3N8) could result in genetic reassortment, potentially creating new influenza strains with unpredictable consequences for animals and humans. Professor Murcia noted parallels to the 2009 swine-origin influenza pandemic, emphasizing the importance of preventing such reassortment events.

The researchers conclude by recommending serologic surveys in premises that keep horses. Such studies, they say, would aid early virus detection, provide a comprehensive picture of the changing ecology of avian influenza viruses, and inform the design of control measures to prevent influenza emergence.

This study highlights the need for:

1. Enhanced surveillance of influenza infections in horses, particularly in regions with high wild bird densities or significant interaction with infected livestock.
2. Strengthened biosecurity measures to reduce interspecies transmission in agricultural settings.
3. Further research into the mechanisms of avian influenza spillover and the potential for new virus emergence.

For more details, see: 

 

Batchuluun Damdinjav, Savitha Raveendran, Laura Mojsiejczuk, Ulaankhuu Ankhanbaatar, Jiayun Yang, Jean-Remy Sadeyen, Munir Iqbal, Daniel R. Perez, Daniela S. Rajao, Andrew Park, Mafalda Viana, and Pablo R. Murcia (2025)

Evidence of Influenza A(H5N1) Spillover Infections in Horses, Mongolia.

Emerging Infectious Diseases, 31(1) 

https://doi.org/10.3201/eid3101.241266 

https://www.gla.ac.uk/news/headline_1134067_en.html

Inflammatory marker increase after routine vaccination

 Routine vaccination can lead to a temporary increase in Serum Amyloid A (SAA), according to a recent study in the USA.

Serum amyloid A (SAA) is an acute-phase protein, meaning its levels in the blood increase rapidly in response to infection, injury, or stress. Due to its rapid increase during inflammatory conditions, SAA is often used in horses as a biomarker to assess inflammation or infection 

 

Researchers at the Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, conducted a two-part study to monitor the response to vaccination. Cassandra M. Baumgarten was the lead author of the study, which was published in the Journal of the American Veterinary Medical Association.

 

The study included a total of 36 clinically normal horses. Twenty-eight horses received routine booster vaccinations recommended for horses in the southern states of the USA (rabies, tetanus, West Nile virus, Eastern and Western equine encephalomyelitis, equine herpesvirus-1/-4, and influenza). Eight horses received placebo injections of saline.

 

The research team conducted daily clinical examinations of the horses, which included measuring their temperature and collecting blood samples to monitor serum amyloid A (SAA) levels for the first ten days after vaccination.

 

They found that, compared to the control group, vaccinated horses had higher SAA concentrations for up to ten days after vaccination, generally returning to normal by the ninth day. About 85.7% of the horses had their SAA levels return to normal within ten days of vaccination.

 

Fever (temperature >38.4°C) was observed in 78.6% of the horses after vaccination, but there was no correlation between fever and SAA concentration.

 

The authors suggest that elevated SAA levels for 10 days after vaccination and fever lasting 12 to 24 hours cannot be used as indicators of illness. They recommend that clinicians, when assessing a patient’s condition after vaccination, should not rely on just one or two clinical signs but rather evaluate the patient as a whole. They also state that measuring SAA for 10 days post-vaccination cannot reliably indicate illness.

 

Based on their findings that routine vaccination increases SAA concentrations, the authors suggest that when advising horse owners about travel or competition, practitioners should recommend a recovery period following vaccination.

 

They also suggest the need for further studies to investigate the effect of travel or competition on the antibody response.

 

 

 

For more details, see: 

 

Baumgarten, C. M., Delph Miller, K. M., Davis, E. G., Beard, L. A., Blevins, C. A., Wottowa, M., Hill, M., & Larson, R. L. (2024). 

Serum amyloid A increases following routine vaccination of healthy adult horses. 

Journal of the American Veterinary Medical Association, 262(9), 1181-1187. 

https://doi.org/10.2460/javma.24.04.0244

North American horse owners sought for biosecurity study

Even with vaccination and modern medicines, biosecurity plays a crucial role in preventing the spread of infectious disease.

 The Equine Disease Communication Center, with the support of the United States Department of Agriculture, is conducting a study into the awareness and knowledge of biosecurity in the horse industry. Based at the American Association of Equine Practitioners (AAEP) headquarters in Lexington, Kentucky, the EDCC provides real-time and accurate information about diseases, vaccination and biosecurity.

 

They have devised an online survey, which they say will take about ten minutes to complete. The findings will be shared with all parts of the horse industry and used to create educational information and resources to help owners protect their horses. 

 

“Dealing with Covid-19 has highlighted the need for biosecurity procedures to reduce risk of infection; however, most horse owners are still not fully aware of the threat to their horses from both endemic and foreign animal diseases either at home or when traveling,” said Dr. Nathaniel White, EDCC director. “We need to understand the gaps in biosecurity knowledge. Armed with that information, we will create specific plans for facilities and events, enabling the industry to react to domestic and foreign disease threats.”

 

Owners or carers of horses in the USA and Canada are asked to participate in the survey

 

To take part in the survey, go to:

 

https://www.research.net/r/EDCCowner

 

For more about the EDCC, see:

 

https://www.equinediseasecc.org

Minimising Risk from Equine Infectious Disease

Each year the Beaufort Cottage Educational Trust puts on a series of lectures in honour of Mr Gerald Leigh and his passion for the Thoroughbred horse and its health and welfare. 

This year, because of the coronavirus pandemic it was not possible for the meeting to go ahead as planned in Newmarket, however, the lectures are now available to view online.

Topics covered were:

Gastrointestinal disease in the first year of life: how to minimise risks

Dealing with infectious challenges in young horses on training yards

Herpes virus: can we defeat a uniquely challenging foe?

The European flu epizootic: what are the lessons learned?

To view the lectures, go to :

https://www.beaufortcottage.com/news-events/

Free live streaming of National Equine Forum

The 27^th National Equine Forum takes place in London on Thursday 7^th March 2019 from 10am – 4.30pm.

The Forum programme will include:

• Brexit and what it means for the horse industry in practical terms
• Equine health, including the latest information on equine flu
• How to make the most of the Central Equine Database
• The latest thoroughbred welfare racing initiatives
•  Preliminary results of the National Equestrian Survey
•  Horse and rider fitness
•  Equine stereotypical behaviours
• The Sir Colin Spedding Memorial lecture: Dr Simon Curtis FWCF on farriery
• Panel discussion: How do charities fit into the modern world?

Tickets have now sold out, but you don’t have to miss out if you don’t have one as you can watch the FREE live streaming on the NEF website. Go to: http://www.nationalequineforum.com/

It is also available via Equestrian Pro TV and the International channel Clip My Horse.

Experts to advise on equine infectious diseases

Thanks to the opportunities of modern transport, it's not only horses that can travel the world. They may also take with them their infectious diseases.

The recent equine influenza outbreak in Australia showed what can happen when susceptible horses are exposed to infection.

So with all the current scientific knowledge about  vaccination, immunity and infectious disease in horses, What can be done to prevent, control  limit the risk of similar outbreaks disasters events happening in the future.

Recently a group know as the Prevention of Equine Infectious Disease Guidelines Group (PrEquID) has been set up to compile recommendations for preventing and managing major equine infectious diseases, based on current scientific knowledge and available vaccines.

After an initial meeting in November 2009, the group met again in March 2010, to discuss guidelines for Equine Influenza and Equine Herpes virus infections. These diseases are widely considered to have a significant impact on the horse industry, based on disease outcome, economic impact, veterinary care and travel restrictions.

Practical, evidence-based recommendations are currently being finalised and will be made available shortly.

“Our aim is to develop overarching international guidelines for the management of infectious diseases,” said Professor Marian C Horzinek, Chairman of PrEquID. “These should contain practical, evidence-based recommendations for disease control and horse movement.”

Professor Peter Timoney, of the University of Kentucky, added, “the equine industry worldwide is facing an unprecedented threat from the challenge of infectious diseases. It’s a huge industry involving a complex range of stakeholders, including veterinarians, owners, breeders, trainers, shippers and regulators. We must set aside individual and national agendas and concentrate on the bigger picture if we’re to achieve greater international control over the spread of equine diseases and protect our industry for the future.”

The establishment of PrEquID was initiated and sponsored by Fort Dodge Animal Health (a division of Wyeth). With the acquisition of Wyeth by Pfizer in 2009, this initiative is now supported by Pfizer Animal Health.