2.1 Sample collection and nucleic acid extraction
A total of 59 fecal swabs were collected from dogs in Vietnam residing in Hanoi (n = 19), Da Nang (n = 16), and Ho Chi Minh (n = 24) cities during July 2017 to August 2018. Samples were primarily tested for parvovirus and coronavirus infection using the rapid ELISA testkit (Bionote, South Korea). Essential information of the animals, including sex, age, breed, and vaccination status was also recorded (Supplementary Table S2). The swab was immersed in 0.5 mL sterile phosphate buffer saline pH 7.4 and stored at -80 0C until used. Viral DNA was extracted using a viral DNA/RNA extraction kit II (Geneaid Biotech, Taiwan) following the manufacturer’s recommendations.