Molecular detection of Porcine astrovirus in Sichuan Province, China

Background: Porcine astrovirus (PoAstV) is widely distributed worldwide, and is highly prevalent among piglets with or without diarrhea, existing as at least five distinct lineages (PoAstV1-PoAstV5) within the genus Mamastrovirus. However, our knowledge of the diversity and epidemiology of PoAstV in China is limited. Results: In this study, fecal samples from 21/120 (17.5 %) domestic pigs, including 18/100 (18 %) diarrheic and 3/20 (15 %) healthy pigs, and from 1/9 (11.1 %) healthy wild boars tested in Sichuan Province were positive for PoAstV on reverse transcription-PCR. Of the 22 positive samples, 13.6 % were positive for PoAstV only, whereas 40.9 % also contained Porcine epidemic diarrhea virus (PEDV), 22.7 % also contained porcine group A rotavirus (PRoVA), and 22.7 % also contained PEDV and PRoVA. A phylogenetic analysis of the RdRp gene revealed genetic heterogeneity among the PoAstV sequences and two lineages were detected in this study, with PoAstV-2 predominant. PoAstV-5 was detected in wild boars for the first time. Conclusions: PoAstV infections exist in Sichuan Province regardless of the disease status in the pig population, either alone or in combination with other enteric viruses, and may be associated with diarrhea.