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Microbes & Immunity

ORIGINAL RESEARCH ARTICLE
Isolation and identification of a highly

pathogenic strain of porcine epidemic diarrhea
virus

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Yongbo Xia , Xiaolu Li 1† , Xiaowei Wang , Xiaoyuan Diao , Wenjing Qiu ,
1†
1
Yihong He , Yue Li 1 , Yunfei Li 1 , Chunyi Xue 1 , Yongchang Cao 1 ,
1
Hanqin Shen , and Zhichao Xu *
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1 State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou,
Guangdong, China
2 Guangdong Provincial Enterprise Key Laboratory of Healthy Animal Husbandry and Environment
Control, Wen’s Foodstuff Group Co. Ltd., Yunfu, Guangdong, China
Abstract

Porcine epidemic diarrhea virus (PEDV) causes acute watery diarrhea and high
mortality in neonatal piglets, resulting in substantial economic losses to the
global swine industry. Here, we successfully isolated a PEDV strain, designated
CHN-CQ-2021, from PEDV-positive diarrheic samples collected from a pig farm in
Chongqing, China. Electron microscopy observation revealed that the CHN-CQ-2021
strain exhibited typical coronavirus morphology and could be recognized by
† These authors contributed equally PEDV-specific antibodies. Phylogenetic analysis of its full-length genome and S
to this work. gene further classified this isolate as a G2b variant strain. Importantly, 1-day-old
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*Corresponding author: newborn piglets were orally challenged with CHN-CQ-2021 at 2 × 10 50% tissue
Zhichao Xu culture infectious dose/mL. Compared with the control group, the infected piglets
(xuzhich5@mail.sysu.edu.cn) developed severe diarrhea with 100% mortality. In addition, viral RNA was detected
Citation: Xia Y, Li X, Wang X, in rectal swabs and multiple tissues, including the intestinal tract and brain, with
et al. Isolation and identification of a
highly pathogenic strain of porcine macroscopic/microscopic intestinal lesions and viral antigen distribution confirmed
epidemic diarrhea virus. Microbes & using histopathology and immunohistochemistry. These findings demonstrate the
Immunity. 2025;2(4):110-121. presence of a pathogenic PEDV strain in Chongqing, China, capable of causing severe
doi: 10.36922/MI025260059 neonatal piglets’ enteric disease.
Received: June 28, 2025
Revised: July 24, 2025 Keywords: Porcine epidemic diarrhea virus; Isolation and identification; Pathogenicity;
Accepted: September 05, 2025 Newborn piglets; China
Published online: October 3, 2025
Copyright: © 2025 Author(s).
This is an Open-Access article 1. Introduction
distributed under the terms of the
Creative Commons Attribution Porcine intestinal infectious diseases pose significant threats to the swine industry and
License, permitting distribution,
and reproduction in any medium, have exhibited an increasing prevalence in multiple regions across global pig farming
provided the original work is countries in recent years. Various pathogens, including viruses (such as norovirus,
properly cited. astrovirus, and rotavirus) and bacteria (such as Salmonella, Campylobacter, and Escherichia
1-6
Publisher’s Note: AccScience coli), can cause diarrhea in both humans and animals. Among various pathogens, viral-
Publishing remains neutral with induced enteric diseases are particularly severe, resulting in substantial economic losses
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regard to jurisdictional claims in
published maps and institutional to the global swine sector. At present, clinically significant viral swine enteric pathogens
affiliations. include transmissible gastroenteritis virus, porcine rotavirus, porcine epidemic diarrhea
Volume X Issue X (2025) 110 doi: 10.36922/MI025260059