Introduction
China has a wide range of duck farming industries and has been a global
leader in commercial duck production. However, with the rapid
development of large-scale industries and increase in stocking density,
infectious disease of ducks, especially those caused by the avian
influenza virus (AIV), Newcastle disease virus (NDV), Tembusu Virus
(TMUV), and duck circovirus (DuCV) have become increasingly frequent
(Fan et al., 2014; L. Xie et al., 2012; Z. Xie et al., 2013; Yun et al.,
2012). These infectious diseases not only cause severe losses in the
duck industry, but also affect the safety of human life, such as in case
of AIV and TMUV infections (Cao et al., 2011; S. Su et al., 2015).
TMUV belongs to the genus Flavivirus and familyFlaviviridae . Its genome encodes three structural proteins and
seven nonstructural proteins (Bai et al., 2013; Mackenzie & Williams,
2009; Zhao et al., 2015). TMUV was first isolated in 1955 in Kuala,
Malaysia, and was reported in China in 2010 (Platt et al., 1975; J. Su
et al., 2011; Yun et al., 2012). The clinical symptoms caused by TMUV
include depression, thin body condition, severely reduced egg
production, severe neurological signs, and even death (Ti et al., 2015;
Zhu et al., 2012). Since 2010, TMUV has become one of the most
economically important infectious diseases of ducks in China (Wang et
al., 2011; Yu et al., 2013).
As a member of the genus Flavivirus , the relevance of TMUV to
human and animals is unclear (Zhang, Chen, Mahalingam, Wang, & Cheng,
2017). However, other members of Flavivirus such as West Nile
virus (WNV), dengue virus (DENV), yellow fever virus (YFN), Japanese
encephalitis virus (JEV), and Zika virus cause serious diseases in
humans, including mild febrile symptoms and fatal hemorrhagic or
neurologic disease every year worldwide (Q. Chen et al., 2020; Gubler,
2002; Hayes et al., 2005; Lanciotti et al., 1999). In nature, birds
usually serve as amplifying hosts, including for WNV, Sitiawan virus,
Usutu virus, and Bagaza virus. Notably, there has been a survey
reporting evidence that TMUV has the potential to be transmitted to
humans by infected birds, emphasizing the need for further study of the
virus (Aguero et al., 2011; Barnard, Buys, Du Preez, Greyling, &
Venter, 1980; Becker et al., 2012; Gould & Solomon, 2008; Kono et al.,
2000; Niu et al., 2018; Weissenbock et al., 2002; Zhang et al., 2017).
In this study, we obtained the TMUV gene sequences reported across China
from NCBI. Then, the epidemiologic, genetic diversity, and evolutionary
dynamics of TMUV were analyzed through bioinformatics research methods.
The findings of this study are expected to aid in the prevention and
control of TMUV in the future.