2.1 Sample collection and DNA preparation
From 2016 to 2019, a total of 281 samples including 236 intestinal
tissue samples and 45 fecal samples were collected from diarrheal
piglets in 37 different pig farms in 18 cities of central China. Each
sample was collected from different pigs, and the origin and the number
of samples were summarized in Table 1.
Samples were diluted 1:10 with phosphate-buffered saline (PBS, pH7.4),
and the suspensions were vortexed and centrifuged at 12 000 × g for 5
min at 4°C to collect the clarified supernatants. The viral DNA was
extracted using an UNlQ-10 Column Virus Genomic DNA Isolation Kit
(Sangon Biotech Shanghai Co, Ltd., China) according to the
manufacturer’s instructions, and stored at -80°C.