Central Veterinary Research Laboratory, Dubai, UAE.
Istituto Zooprofilattico Sperimentale, dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy.
Equine Vet J. 2021 Jul;53(4):826-833. doi: 10.1111/evj.13363. Epub 2020 Oct 29.
African horse sickness (AHS) is a devastating viral disease of equids that was first recorded in 1327. Currently, prevention and control of the disease are based on attenuated vaccines and midge control. It has been shown that attenuated Orbivirus vaccines are not always safe as they may reverse to virulence.
In the Emirate of Dubai, a vaccination experiment was carried out with an inactivated AHS vaccine produced at the Central Veterinary Research Laboratory (CVRL), Dubai, UAE to investigate the humoral antibody response of AHS-naïve horses to this vaccine. Our vaccination experiment was performed to establish an AHS vaccine bank in the UAE to protect horses from the disease in case of an outbreak. Therefore, CVRL established an inactivated AHS vaccine containing all nine serotypes which induce high neutralising antibodies.
A total of 10 horses kept in a desert isolation area were subcutaneously and intramuscularly vaccinated with an inactivated vaccine containing all nine AHS serotypes previously isolated from Kenyan horse fatalities. Primary immunisation was followed by two booster immunisations 4 weeks and 6 months apart. After 13 months, an annual booster was administered.
Blood samples were regularly withdrawn for ELISA and virus neutralisation testing. Additionally, EDTA blood was tested every second day for 14 days post each vaccination for the presence of AHS virus or its RNA.
Results show that ELISA and virus neutralising antibodies appeared after the first booster, declined after 4-6 months and therefore three vaccinations and an annual vaccination are necessary to achieve high protective virus neutralising antibodies.
No challenge infection was carried out due to the lack of a safe facility in the UAE.
Before more advanced AHS vaccines become a reality, inactivated vaccines containing all nine serotypes should be used as they produce high ELISA and neutralising antibodies.
非洲马瘟（AHS）是一种毁灭性的马属动物病毒病，于 1327 年首次记录。目前，该病的预防和控制基于减毒疫苗和蠓控制。事实证明，减毒的环状病毒疫苗并不总是安全的，因为它们可能会恢复毒力。
在迪拜酋长国，使用由阿联酋迪拜中央兽医研究实验室（CVRL）生产的灭活 AHS 疫苗进行了疫苗接种实验，以研究 AHS 初免马对该疫苗的体液抗体反应。我们进行疫苗接种实验是为了在阿联酋建立 AHS 疫苗库，以防疫情爆发时保护马匹免受疾病侵害。因此，CVRL 建立了一种包含所有 9 种血清型的灭活 AHS 疫苗，这些血清型能诱导高中和抗体。
总共对 10 匹饲养在沙漠隔离区的马进行了皮下和肌肉接种，接种了先前从肯尼亚马死亡中分离出来的含有所有 9 种 AHS 血清型的灭活疫苗。初次免疫后，每隔 4 周和 6 个月进行两次加强免疫。13 个月后，每年进行一次加强免疫。
定期采集血样进行 ELISA 和病毒中和试验。此外，在每次接种后第 14 天，每隔一天采集 EDTA 血样，检测 AHS 病毒或其 RNA 的存在。
结果表明，ELISA 和病毒中和抗体在第一次加强免疫后出现，在 4-6 个月后下降，因此需要进行三次接种和每年一次接种，以获得高保护性的病毒中和抗体。
由于阿联酋缺乏安全设施，因此没有进行挑战感染。
在更先进的 AHS 疫苗成为现实之前，应使用包含所有 9 种血清型的灭活疫苗，因为它们能产生高 ELISA 和中和抗体。
