Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Viruses. 2024 Jul 3;16(7):1070. doi: 10.3390/v16071070.
In populations of healthy show horses, the subclinical transmission and circulation of respiratory pathogens can lead to disease outbreaks. Due to recent outbreaks of equine herpesvirus-1 myeloencephalopathy (EHM) in the USA and Europe, many show organizers have instituted various biosecurity protocols such as individual horse testing, monitoring for early clinical disease and increasing hygiene and cleanliness protocols. The aim of this study was to determine the accuracy of detecting EHV-1 in the various environmental samples collected from the stalls of subclinical shedders. Four healthy adult horses were vaccinated intranasally with a modified-live EHV-1 vaccine in order to mimic subclinical shedding. Three additional horses served as non-vaccinated controls. All the horses were stabled in the same barn in individual stalls. Each vaccinated horse had nose-to-nose contact with at least one other horse. Prior to the vaccine administration, and daily thereafter for 10 days, various samples were collected, including a 6" rayon-tipped nasal swab, an environmental sponge, a cloth strip placed above the automatic waterer and an air sample. The various samples were processed for nucleic acid purification and analyzed for the presence of EHV-1 via quantitative PCR (qPCR). EHV-1 in nasal secretions was only detected in the vaccinated horses for 1-2 days post-vaccine administration. The environmental sponges tested EHV-1 qPCR-positive for 2-5 days (median 3.5 days) in the vaccinated horses and 1 day for a single control horse. EHV-1 was detected by qPCR in stall strips from three out of four vaccinated horses and from two out of three controls for only one day. EHV-1 qPCR-positive air samples were only detected in three out of four vaccinated horses for one single day. For the vaccinated horses, a total of 25% of the nasal swabs, 35% of the environmental stall sponges, 7.5% of the strips and 7.5% of the air samples tested qPCR positive for EHV-1 during the 10 study days. When monitoring the subclinical EHV-1 shedders, the collection and testing of the environmental sponges were able to detect EHV-1 in the environment with greater frequency as compared to nasal swabs, stationary strips and air samples.
在健康的展示马群中，呼吸道病原体的亚临床传播和循环会导致疾病爆发。由于最近在美国和欧洲爆发了马疱疹病毒 1 性脑脊髓炎（EHM），许多展览组织者制定了各种生物安全协议，例如对每匹马进行单独检测、监测早期临床疾病以及增加卫生和清洁协议。本研究的目的是确定从亚临床病马的马厩中收集的各种环境样本中检测 EHV-1 的准确性。四匹健康的成年马通过鼻腔接种改良活 EHV-1 疫苗以模拟亚临床排毒。另外三匹马作为未接种疫苗的对照。所有的马都在单独的马厩中饲养。每匹接种疫苗的马都与至少一匹其他马进行了鼻对鼻接触。在疫苗接种前，以及此后的 10 天内，每天采集各种样本，包括 6" 纤维头鼻腔拭子、环境海绵、自动饮水机上方的布条和空气样本。对各种样本进行核酸纯化处理，并通过定量 PCR（qPCR）分析是否存在 EHV-1。仅在接种疫苗的马中，在接种疫苗后 1-2 天检测到鼻腔分泌物中的 EHV-1。接种疫苗的马中，环境海绵的 EHV-1 qPCR 阳性结果持续了 2-5 天（中位数为 3.5 天），而只有一匹对照马持续了 1 天。在 4 匹接种疫苗的马和 3 匹对照马中的 2 匹中，仅 1 天检测到拭条 EHV-1 qPCR 阳性。在 4 匹接种疫苗的马中，只有 1 天检测到 1 份空气样本的 EHV-1 qPCR 阳性。对于接种疫苗的马，在 10 天的研究期间，总共 25%的鼻腔拭子、35%的环境马厩海绵、7.5%的拭条和 7.5%的空气样本通过 qPCR 检测到 EHV-1 呈阳性。在监测亚临床 EHV-1 排毒者时，与鼻腔拭子、固定拭条和空气样本相比，环境海绵的采集和检测能够更频繁地检测到环境中的 EHV-1。
