Detection of a novel circovirus PCV3 in pigs with cardiac and multi-systemic inflammation.
Porcine circovirus 2 causes different clinical syndromes resulting in a significant economic loss in the pork industry. Three pigs with unexplained cardiac and multi-organ inflammation that tested negative for PCV2 and other known porcine pathogens were further analyzed.



Histology was used to identify microscopic lesions in multiple tissues. Metagenomics was used to detect viral sequences in tissue homogenates. In situ hybridization was used to detect viral RNA expression in cardiac tissue.



In all three cases we characterized the genome of a new circovirus we called PCV3 with a replicase and capsid proteins showing 55 and 35 % identities to the genetically-closest proteins from a bat-feces associated circovirus and were even more distant to those of porcine circovirus 1 and 2. Common microscopic lesions included non-suppurative myocarditis and/or cardiac arteriolitis. Viral mRNA was detected intralesionally in cardiac cells. Deep sequencing in tissues also revealed the presence of porcine astrovirus 4 in all three animals as well as rotavirus A, porcine cytomegalovirus and porcine hemagglutinating encephalomyelitis virus in individual cases.



The pathogenicity and molecular epidemiology of this new circovirus, alone or in the context of co-infections, warrants further investigations.
Blood Systems Research Institute, San Francisco, CA, 94118, USA.|Department of Laboratory Medicine, University of California at San Francisco, San Francisco, CA, 94118, USA.
Tung Gia
TG
Phan
Veterinary Diagnostic Laboratory, University of Minnesota, Saint Paul, MN, 55108, USA.|Instituto Nacional de Investigación Agropecuaria, La Estanzuela, Colonia, 70000, Uruguay.
Federico
F
Giannitti
Veterinary Diagnostic Laboratory, University of Minnesota, Saint Paul, MN, 55108, USA.
Stephanie
S
Rossow
Veterinary Diagnostic Laboratory, University of Minnesota, Saint Paul, MN, 55108, USA.
Douglas
D
Marthaler
Veterinary Diagnostic Laboratory, University of Minnesota, Saint Paul, MN, 55108, USA.
Todd P
TP
Knutson
Blood Systems Research Institute, San Francisco, CA, 94118, USA.|Department of Laboratory Medicine, University of California at San Francisco, San Francisco, CA, 94118, USA.
Linlin
L
Li
Blood Systems Research Institute, San Francisco, CA, 94118, USA.
Xutao
X
Deng
Veterinary Diagnostic Laboratory, University of Minnesota, Saint Paul, MN, 55108, USA.
Talita
T
Resende
Veterinary Diagnostic Laboratory, University of Minnesota, Saint Paul, MN, 55108, USA.
Fabio
F
Vannucci
Blood Systems Research Institute, San Francisco, CA, 94118, USA. delwarte@medicine.ucsf.edu.|Department of Laboratory Medicine, University of California at San Francisco, San Francisco, CA, 94118, USA. delwarte@medicine.ucsf.edu.
Eric
E
Delwart
D000818:Animals; D018173:Circoviridae Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000145:classification* / Q000302:isolation & purification*; D006651:Histocytochemistry; D017403:In Situ Hybridization; D056186:Metagenomics; D008853:Microscopy; D013552:Swine; D013553:Swine Diseases / Q000473:pathology* / Q000821:virology*
Arteriolitis; Circovirus; Metagenomics; Myocarditis; Pig; Vasculitis