Vaccine Development Unit, Department of Infectious Disease Research, King Abdullah International Medical Research Center, Riyadh 11564, Saudi Arabia.
College of Science, King Saud University, Riyadh 11564, Saudi Arabia.
Viruses. 2020 Oct 27;12(11):1215. doi: 10.3390/v12111215.
MERS-CoV is a zoonotic virus that has emerged in humans in 2012 and caused severe respiratory illness with a mortality rate of 34.4%. Since its appearance, MERS-CoV has been reported in 27 countries and most of these cases were in Saudi Arabia. So far, dromedaries are considered to be the intermediate host and the only known source of human infection. This study was designed to determine the seroprevalence and the infection rate of MERS-CoV in slaughtered food-camels in Riyadh, Saudi Arabia. A total of 171 nasal swabs along with 161 serum samples were collected during the winter; from January to April 2019. Nasal swabs were examined by Rapid test and RT-PCR to detect MERS-CoV RNA, while serum samples were tested primarily using S1-based ELISA Kit to detect MERS-CoV (IgG) antibodies and subsequently by MERS pseudotyped viral particles (MERSpp) neutralization assay for confirmation. Genetic diversity of the positive isolates was determined based on the amplification and sequencing of the spike gene. Our results showed high prevalence (38.6%) of MERS-CoV infection in slaughtered camels and high seropositivity (70.8%) during the time of the study. These data indicate previous and ongoing MERS-CoV infection in camels. Phylogenic analysis revealed relatively low genetic variability among our isolated samples. When these isolates were aligned against published spike sequences of MERS-CoV, deposited in global databases, there was sequence similarity of 94%. High seroprevalence and high genetic stability of MERS-CoV in camels indicating that camels pose a public health threat. The widespread MERS-CoV infections in camels might lead to a risk of future zoonotic transmission into people with direct contact with these infected camels. This study confirms re-infections in camels, highlighting a challenge for vaccine development when it comes to protective immunity.
MERS-CoV 是一种人畜共患病毒，于 2012 年在人类中出现，并导致严重的呼吸道疾病，死亡率为 34.4%。自出现以来，MERS-CoV 已在 27 个国家报告，其中大多数病例发生在沙特阿拉伯。到目前为止，单峰驼被认为是中间宿主，也是人类感染的唯一已知来源。本研究旨在确定沙特阿拉伯利雅得屠宰食用骆驼中 MERS-CoV 的血清流行率和感染率。2019 年 1 月至 4 月冬季期间共采集了 171 份鼻拭子和 161 份血清样本。鼻拭子通过快速检测和 RT-PCR 检测 MERS-CoV RNA，血清样本首先使用基于 S1 的 ELISA 试剂盒检测 MERS-CoV（IgG）抗体，然后使用 MERS 假病毒颗粒（MERSpp）中和试验进行确认。根据尖峰基因的扩增和测序确定阳性分离株的遗传多样性。我们的结果表明，屠宰骆驼中 MERS-CoV 感染的流行率很高（38.6%），研究期间的血清阳性率很高（70.8%）。这些数据表明骆驼中存在先前和正在进行的 MERS-CoV 感染。系统发育分析显示，我们分离的样本之间遗传变异相对较低。当这些分离株与全球数据库中已发表的 MERS-CoV 尖峰序列进行比对时，序列相似性为 94%。骆驼中 MERS-CoV 的高血清流行率和高遗传稳定性表明，骆驼对公共卫生构成威胁。骆驼中广泛存在的 MERS-CoV 感染可能导致未来与这些受感染骆驼直接接触的人发生人畜共患传播的风险。本研究证实了骆驼的再感染，这突显出在保护性免疫方面，疫苗开发面临挑战。
