Description of the identified case of a new porcine circovirus, PCV3, in France
Description du premier cas d’identification d’un nouveau circovirus porcin, le PCV3, en France
Abstract
Porcine circovirus 3 (PCV3) was first identified by meta-genomics in the United States in 2015 on a farm that had recorded an increase in the mortality rate, a decrease in sow reproduction and clinical signs compatible with nephropathy dermatitis syndrome. Epidemiologically, PCV3 has gradually spread to several countries, including some in Europe, and is currently widely distributed in pigs and wild boars throughout the world. In 2019, a PCV3 infection was identified for the first time in France during suspected atypical circovirosis on a farm with post-weaning growth retardation and withering at the beginning of fattening. Histological examinations performed on 3 animals with typical clinical signs showed lymphoid depletion, lympho-histiocytic infiltration and the presence of syncytial cells that are typical lesions of circovirosis. Immuno-histochemical examination with an anti-CAP PCV2 antibody was found to be positive, but detection of the PCV2 viral genome by qPCR was negative. Qualitative and quantitative PCR of the PCV3 genome carried out on samples from fattening pigs showing signs of atypical circovirosis were found to be positive. SANGER sequencing of PCR products confirmed the presence of the PCV3 viral genome in these pigs. These results show for the first time the detection of PCV3 in the French pig herd associated with clinical manifestations of circovirosis. Research is currently underway to evaluate the real involvement of PCV3 in the various syndromes associated with its presence.