Coinfection and Genetic Characterization of Porcine Astrovirus in Diarrheic Piglets in China From 2015 to 2018.

Mingjun Su,Shanshan Qi,Donghua Guo,Baishuang Yin,Dan Yang,Dongbo Sun

doi:10.3389/fvets.2020.00462

Abstract

Porcine astrovirus (PAstV) is broadly distributed globally and exists as at least five distinct genotypes. PAstV, which was recently identified as an important pathogen of diarrhea in piglets, is widely distributed in China. However, few studies have investigated the coinfection and genetic characterization of PAstV in diarrheic piglets in China. In this study, 89 PAstV-positive samples were identified in 543 diarrhea samples in China from 2015 to 2018, of which 75.28% (67/89) were coinfected with three to five different porcine pathogens, while none were positive for PAstV only. Among the 543 diarrhea samples, statistical analysis showed that PAstV-induced diarrhea was potentially associated with coinfection of PEV (p < 0.01) and GARV (p < 0.01). Phylogenetic analysis showed that the 27 identified PAstV strains belong to three different genotypes and that PAstV-2 (81.48%, 22/27) was predominant in diarrheic piglets in China, followed by PAstV-4 (11.11%, 3/27) and PAasV-5 (7.41%, 2/27). Sequence analysis revealed that the 27 RdRp genes identified in this study had nucleotide homologies of 53.8–99.5%. In addition, the RdRp gene of PAstV-4 strain JL/MHK/2018/0115 harbored a unique insert of three nucleotides (GAA) as compared with other known PAstV-4 strains. Furthermore, the genotypes of PAstV varied among different geographical locations, although PAstV-2 was the most widely distributed in China. These data demonstrate that PAstV coinfection with other porcine pathogens was common and there was genetic diversity of PAstV in diarrheic piglets in China.

Highlights

Porcine astrovirus (PAstV), belonging to the family Astroviridae, genus Mamastrovirus, is a nonenveloped, single-strand, positive-sense RNA virus [1]
The obtained RNA-dependent RNA polymerase (RdRp) genes were genetically characterized in order to provide insights into the epidemiology of PAstV circulating among diarrheic piglets in China
Of the 89 PAstV-positive diarrhea samples, the rate of PAstV coinfection with 12 other porcine pathogens ranged from 7.87% (7/89) to 85.39% (76/89) (Figure 1A)

Summary

INTRODUCTION

Porcine astrovirus (PAstV), belonging to the family Astroviridae, genus Mamastrovirus, is a nonenveloped, single-strand, positive-sense RNA virus [1]. PAstV, which has been identified as an important agent of diarrhea [10], and frequently presents as a coinfection with other porcine pathogens [3, 5, 6, 9, 11]. Data regarding coinfections with PAstV in diarrheic piglets in China are limited. Coinfections with PAstV and other porcine pathogens should be monitored in China. 89 PAstV-positive diarrhea samples were collected to investigate the prevalence of PAstV coinfection with 12 other porcine pathogens. The obtained RdRp genes were genetically characterized in order to provide insights into the epidemiology of PAstV circulating among diarrheic piglets in China. Data regarding the detection of porcine circovirus type 3, porcine group A rotavirus (GARV), mammalian reovirus, porcine bocavirus, porcine deltacoronavirus, porcine enterovirus 9/10 (PEV), porcine kobuvirus (PKV), porcine sapelovirus, porcine torovirus, porcine teschovirus, porcine transmissible gastroenteritis virus (TGEV), and torque teno sus virus 2 in the 543 diarrhea samples (including the 89 PAstV-positive samples) were published in our previous reports [9, 17]

MATERIALS AND METHODS

RESULTS AND DISCUSSION

DATA AVAILABILITY STATEMENT

ETHICS STATEMENT