Epidemiological analysis and detection of a 27a-like porcine parvovirus strain with pathogenicity in pregnant sows in Japan

Porcine parvovirus (PPV) is a major cause of reproductive failure in pigs. This study reports the first detection of a PPV 27a-like strain in Japan. A total of 387 samples from 113 cases (2015-2024) were analyzed, revealing 35 PPV-positive cases. Phylogenetic analysis identified the NG2794-2-3/2019 strain as a 27a-like variant. Experimental infection in pregnant sows resulted in fetal death and mummification, confirming pathogenicity. The strain exhibited prolonged viremia, indicating a high transmission risk. Owing to antigenic differences from vaccine strains, conventional PPV vaccines may be ineffective. This study highlights the urgent need for enhanced vaccines to control PPV-related reproductive disorders in Japan.