Detection of equine influenza virus gene in the air around infected horses.
Abstract: Equine influenza virus (EIV) can be transmitted by inhalation of aerosolized droplets, direct contact, and contaminated fomites. However, to our knowledge, there are no reports of the recovery of EIV from the air surrounding infected horses. Here, we evaluated whether EIV can be recovered from the air in the stalls of experimentally infected horses by using an air sampler. Furthermore, we examined whether rapid molecular test kits with reaction times of less than 30 min can detect EIV from air samples for potential field application. Two horses kept in individual stalls were experimentally infected with EIV. Air samples were collected daily by using an air sampler until 13 days post-inoculation (dpi). Viral genes were detected in 26 out of 28 air samples from both horses at 1-13 dpi by real-time RT-PCR. A rapid molecular test kit based on real-time RT-PCR detected viral genes in 23 air samples from one horse at 1-9 and 12 dpi, and from the other at 1-13 dpi. These findings confirm that horses infected with EIV shed the virus into the air. Air sampling is safe for humans and horses and avoids the potential for injury when nasopharyngeal swabs need to be collected from untrained or aggressive horses. EIV RNA was detected in the air samples by using real-time RT-PCR or the rapid molecular test kit before the horses showed clinical signs. Thus, air samplers can detect EIV RNA as early as possible through routine testing in locations such as quarantine facilities.
Copyright © 2025 Elsevier B.V. All rights reserved.
Publication Date: 2025-01-11 PubMed ID: 39823717DOI: 10.1016/j.vetmic.2025.110388Google Scholar: Lookup
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- Journal Article
Summary
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This research article investigates the presence of equine influenza virus (EIV) in the air surrounding infected horses and tests the effectiveness of rapid molecular tests in detecting the virus from air samples.
Methodology
- The researchers carried out an experiment using two horses that were individually kept in stalls and infected with EIV.
- Air samples were collected daily until 13 days post-infection using an air sampler.
- Real-time RT-PCR technology was utilized to detect viral genes in the collected air samples.
- A rapid molecular test kit based on real-time RT-PCR was then used to detect these viral genes. This kit has the advantage of providing results in less than 30 minutes, making it suitable for potential field application.
Findings
- The researchers found that viral genes were present in 26 out of the total 28 air samples collected from both horses at various time intervals ranging from day 1 to 13 post-infection.
- The rapid molecular test kit was able to detect viral genes in 23 air samples from one horse at various intervals, and from the other horse across the entire 13-day post-infection period.
- The findings confirmed that horses infected with EIV shed the virus into the surrounding air, thereby posing an airborne infection risk. This novel finding added new insights as there were previously no reports of EIV in the air around infected horses.
Implications
- This study presents new evidence of the airborne transmission of EIV.
- The use of rapid molecular tests shows promise in quickly detecting EIV in air samples, holding potential for applications in field settings.
- Finding EIV in the air provides further options for testing beyond the typical nasal swabs, particularly useful for dealing with untrained or aggressive horses where swab testing can pose an injury risk.
- Being able to detect EIV in the air before the infected horse shows clinical symptoms could help with early prevention and control of the disease, especially in quarantine facilities.
Cite This Article
APA
Nemoto M, Kawanishi N, Kambayashi Y, Bannai H, Yamanaka T, Tsujimura K.
(2025).
Detection of equine influenza virus gene in the air around infected horses.
Vet Microbiol, 302, 110388.
https://doi.org/10.1016/j.vetmic.2025.110388 Publication
Researcher Affiliations
- Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan. Electronic address: nemoto_manabu@equinst.go.jp.
- Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
- Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
- Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
- Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
- Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
MeSH Terms
- Animals
- Horses
- Orthomyxoviridae Infections / veterinary
- Orthomyxoviridae Infections / virology
- Horse Diseases / virology
- Influenza A Virus, H3N8 Subtype / genetics
- Influenza A Virus, H3N8 Subtype / isolation & purification
- Air Microbiology
- Real-Time Polymerase Chain Reaction / veterinary
- RNA, Viral / genetics
Conflict of Interest Statement
Declaration of Competing Interest The AerosolSense Sampler was loaned by Thermo Fisher Scientific to the Equine Research Institute, Japan Racing Association. None of the authors had any other conflicts of interest.
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