Pathogenic potential and growth kinetics of Muko virus in mice and human-derived cells

Gianne Eduard L. Ulanday, Satoshi Shimada, Ngwe Tun Mya Myat, Takeshi Nabeshima, Kouichi Morita, Daisuke Hayasaka

Ticks have been long known as vectors of various pathogens, some of which can cause high fatality rates among infected individuals. Our enhanced tick surveillance around Nagasaki, Japan, led to the isolation and identification of a new strain of a recently identified Orbivirus, Muko virus (MUV). The orbiviruses have a wide host range, including humans, and is related to a spectrum of clinical outcomes. However, the zoonotic potential of some members of the genus, although reported, were not clearly elucidated. Hence, it is imperative to characterize newly isolated orbiviruses and investigate its ability to endanger public health. In this study, we explored the in vivo pathogenicity of a newly isolated MUV strain (MUV-Hay) using a mouse model and demonstrated its growth kinetics in human-derived cells. Our results showed the ability of MUV-Hay to propagate in human neuronal and renal cells with some cytopathic effect. Furthermore, intracerebral inoculation of our new isolate caused high mortality in adult A129 mice. Our study provided a first step to experimentally test the hypothesis, that MUV can replicate and produce cytopathic effect in human cells and demonstrate virulence in adult mice.