Evolutionary evidence for multi-host transmission of cetacean morbillivirus

Cetacean morbillivirus (CeMV) has emerged as the pathogen that poses the greatest risk of triggering epizootics in cetacean populations worldwide, and has a high propensity for interspecies transmission, including sporadic infection of seals. In this study, we investigated the evolutionary history of CeMV by deep sequencing wild-type viruses from tissue samples representing cetacean species with different spatiotemporal origins. Bayesian phylogeographic analysis generated an estimated evolutionary rate of 2.34 × 10⁻⁴ nucleotide substitutions/site/year and showed that CeMV evolutionary dynamics are neither host-restricted nor location-restricted. Moreover, the dolphin morbillivirus strain of CeMV has undergone purifying selection without evidence of species-specific mutations. Cell-to-cell fusion and growth kinetics assays demonstrated that CeMV can use both dolphin and seal CD150 as a cellular receptor. Thus, it appears that CeMV can readily spread among multiple cetacean populations and may pose an additional spillover risk to seals.

鲸类麻疹病毒（Cetacean morbillivirus，CeMV）已成为全球范围内引发鲸类种群动物流行病风险最高的病原体，且具有极高的跨物种传播倾向，包括偶发感染海豹的情况。本研究通过对来自不同时空来源的鲸类物种组织样本中的野生型病毒进行深度测序，解析了CeMV的进化历史。贝叶斯系统地理学分析估算得到的进化速率为2.34×10⁻⁴ 核苷酸替换·位点⁻¹·年⁻¹，结果显示CeMV的进化动态既不受宿主限制，也不受地理区域限制。此外，CeMV的海豚麻疹病毒毒株经历了纯化选择，未发现物种特异性突变的证据。细胞间融合与生长动力学实验证实，CeMV可同时利用海豚和海豹的CD150作为细胞受体。综上，CeMV可在多种鲸类种群中高效传播，且可能对海豹构成额外的跨物种溢出感染风险。