Tembusu virus (TMUV) is a positive-sense RNA virus that is associated
with severe reduction in egg production and even death in ducks. TMUV
infection shows high incidence and is a threat to the global duck
industry. However, the possible origin, genotype, and codon usage bias
of TMUV are not very clear. Here, we addressed these questions by
analyzing the available genomic sequences from China. The results showed
that the ancestor of avian TMUV was most likely a mosquito TMUV.
Moreover, three TMUV clades were identified by three different
phylogenetic analysis methods. The TMUV genome exhibits a stronger
mutation pressure than natural selection pressure. TMUV has the
potential to cause an infection outbreak among humans, thereby posing a
major threat to public health. Our findings provide important insights
that reveal the ongoing TMUV spread in China and can aid in future
prevention and control.