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Microbes & Immunity Isolation and identification of PEDV strain CHN-CQ-2021

and death. 34,35 The PEDV GDS01 strain isolated in another of Agriculture and Rural-Youth top talent project
study over a decade ago was initially highly pathogenic to (#NYQN2024001) and the Key-Area Research and
newborn piglets. However, its virulence has attenuated due Development Program of Guangdong Province
36
to extensive in vitro passaging, which could affect vaccine (#2022B1111030001).
evaluation and related studies. Orally inoculating 1-day-
old newborn piglets with the CHN-CQ-2021 strain caused Conflict of interest
severe diarrhea and 100% mortality in piglets, indicating that The authors declare that they have no competing interests.
this epidemic strain is highly pathogenic and poses a huge
threat to pig farms. Viral nucleic acids could be detected Author contributions
in anal swabs, suggesting that fecal-oral transmission
is a predominant route of PEDV dissemination. In Conceptualization: Zhichao Xu
addition, gross and histological examinations of intestinal Data curation: Yongbo Xia, Xiaolu Li
tissues from infected piglets revealed extensive lesions. Formal analysis: Zhichao Xu
Microscopic observations showed severe cellular damage Funding acquisition: Zhichao Xu
in the jejunum and ileum. Immunohistochemical analysis Investigation: Yongbo Xia, Xiaolu Li
confirmed the predominant localization of PEDV antigens Methodology: Zhichao Xu
in the cytoplasm of enterocytes, consistent with previous Project administration: Yongchang Cao, Zhichao Xu
studies. These findings collectively demonstrate that PEDV Resources: Zhichao Xu, Chunyi Xue, Yongchang Cao
36
CHN-CQ-2021 causes intestinal lesions, resulting in severe Software: Zhichao Xu
diarrhea. Interestingly, PEDV nucleic acids were also detected Supervision: Zhichao Xu, Chunyi Xue, Yongchang Cao
in the brains of virus-infected piglets. The mechanisms Validation: All authors
underlying PEDV entry into the brain and its potential Visualization: Yongbo Xia, Xiaolu Li, Zhichao Xu
neuropathogenicity remain to be elucidated. Importantly, Writing–original draft: Xiaolu Li
we successfully isolated a highly pathogenic PEDV epidemic Writing–review & editing: Zhichao Xu
strain. However, several questions remain to be addressed
in future research. For example, has the virulence of this Ethics approval and consent to participate
strain increased compared to previously circulating strains? The animal study was supervised by the Institutional
If so, what are the underlying mechanisms? Do current Animal Care and Use Committee of Sun Yat-sen University
commercial vaccines confer protective immunity against (IACUC-2023-B0404) and conducted in accordance with
this strain? If not, can this strain serve as a candidate for the regulations and guidelines of this committee.
vaccine development? Clarifying these questions will aid in
better controlling PEDV outbreaks. Consent for publication
5. Conclusion Not applicable.

A novel PEDV strain named CHN-CQ-2021 was isolated Availability of data
from the pathological samples of diarrheic piglets in this The data that support the findings of this study are available
study. Phylogenetic analysis classified this strain as a G2b from the corresponding author on reasonable request.
genotype variant, exhibiting the typical morphological
features of coronavirus. Oral inoculation of newborn piglets References
with the CHN-CQ-2021 strain induced severe clinical
symptoms, including watery diarrhea, dehydration, and high 1. Chen J, Cheng Z, Chen J, Qian L, Wang H, Liu Y. Advances in
human norovirus research: Vaccines, genotype distribution
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and characterization of the CHN-CQ-2021 strain provide a
critical foundation for studying the pathogenic mechanisms doi: 10.1016/j.virusres.2024.199486
of PEDV and developing prevention and control measures. 2. Roach SN, Langlois RA. Intra- and cross-species
transmission of astroviruses. Viruses. 2021;13(6):1127.
Acknowledgments
doi: 10.3390/v13061127
None.
3. Kotloff KL, Platts-Mills JA, Nasrin D, Roose A,
Funding Blackwelder WC, Levine MM. Global burden of diarrheal
diseases among children in developing countries: Incidence,
This work was supported by the grant from the “Special etiology, and insights from new molecular diagnostic
Support Plan” of Guangdong Provincial Department techniques. Vaccine. 2017;35(49):6783-6789.

Volume X Issue X (2025) 119 doi: 10.36922/MI025260059