Molecular characterization of feline caliciviruses isolated from several adult cats with atypical infection showing severe flu-like symptoms on a remote island in Ehime, Japan

In November 2020, a volunteer group reported an outbreak of an infectious disease with a high fatality rate and flu-like symptoms among stray cats in Aoshima, a remote island in Ehime, Japan. Nine adult cats with severe symptoms were hospitalized. Feline calicivirus (FCV) was isolated from pharyngea...

Full description

Saved in:
Bibliographic Details
Main Authors: Yuki Nishisaka, Hikaru Fujii, Fumiko Ono, Sho Kadekaru, Hiroyuki Kogiku, Yumi Une, Shione Takeguchi, Naomi Ohta, Masumi Eto, Chiharu Takeuchi, Seigou Takeuchi, Tetsuko Miki, Akihiko Tokuda, Keiko Ookawa, Yukinobu Tohya, Keita Ishijima, Akiko Okutani, Ken Maeda, Shumpei Watanabe, Shigeru Morikawa
Format: Article
Language:English
Published: Elsevier 2025-03-01
Series:Virus Research
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0168170225000115
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In November 2020, a volunteer group reported an outbreak of an infectious disease with a high fatality rate and flu-like symptoms among stray cats in Aoshima, a remote island in Ehime, Japan. Nine adult cats with severe symptoms were hospitalized. Feline calicivirus (FCV) was isolated from pharyngeal swabs of six hospitalized cats. An outbreak of virulent systemic FCV (VS-FCV) infection was initially suspected because of obvious flu-like symptoms in adult cats; however, no symptoms typically associated with VS-FCV, such as skin ulcers on the limbs, edema, or viremia, were observed. Notably, two of the hospitalized cats that showed severe disease had diarrhea and anemia, and died or had a prolonged illness. These cases reveal atypical symptoms of FCV infection that have not been previously reported. We further isolated typical strains from western Japan (Osaka, Kumamoto, and Ehime) and analyzed the viral genes along with virulent strains from Aoshima. Phylogenetic analysis showed that the Aoshima strain formed a new lineage distinct from known FCVs. The Aoshima strains isolated in the initial outbreak before December 5, 2020, and those isolated after the end of the outbreak, which are suspected pathogenic and typical non-pathogenic strains, respectively, were located in the same cluster and shown to be very similar in sequence. The virulent Aoshima strain, which causes atypical FCV infections in cats, may have been derived by acquiring several mutations from a typical strain that chronically infects cats on a remote island.
ISSN:1872-7492