Comparison of three animal viruses with circular single-stranded DNA genomes

Abstract

No common antigenic determinants and no DNA sequence homologies were detected when three animal viruses, chicken anaemia agent (CAA), porcine circovirus (PCV), and psittacine beak and feather disease virus (PBFDV), all of which possess circular single-stranded DNA genomes, were compared. Negative contrast electron microscopy showed that PCV and PBFDV particles were 30% smaller than CAA particles and lacked the surface structure of CAA.

Revisiting the taxonomy of the family Circoviridae: establishment of the genus Cyclovirus and removal of the genus Gyrovirus

“…Circovirus genomes range in size from *1.8 to *2.1 kb and are packaged within non-enveloped virions that have an icosahedral T = 1 structure and have an average diameter of *15 -25 nm [10,69,82,83]. All circovirus genomes have an ambisense organisation containing open reading frames (ORFs) arranged on different strands of a dsDNA replicative form.…”

“…As early as 1991 it was noted that CAV virions had marked physicochemical and morphological differences when compared to BFDV and PCV, which were indistinguishable under the same conditions [82]. Therefore, even before animal viruses with circular ssDNA genomes were classified, it was 'inadvisable' to place CAV in the same family as BFDV and PCV based on comparative electron microscopy [82].…”

“…Although CAV virions are non-enveloped and icosahedral, they are larger than circovirus virions and have a unique structure with protruding pentagonal shaped units compared to flat pentameric units observed in circoviruses [10,82]. In addition to appearing structurally unrelated to circoviruses, CAV has a genomic architecture that is radically different from that of circoviruses.…”

Features of Porcine Circovirus-2 Disease: Correlations between Lesions, Amount and Distribution of Virus, and Clinical Outcome

“…Porcine circovirus 2 (PCV-2), the smallest known autonomously replicating mammalian DNA viral pathogen, 27,32,44 is established as the necessary cause of postweaning multisystemic wasting syndrome (PMWS) in swine. 1,2,11,12,17,22 In addition to PMWS, PCV-2 infection is also associated with porcine dermatitis and nephropathy syndrome 1,9,14,31,43 and reproductive disease including still births and abortions.…”

Pigeon circovirus infection: Pathological observations and suggested pathogenesis

“…Three other circoviruses are known to be causal agents of spontaneous diseases: chicken anaemia virus (CAV) infection in fowl, psittacine beak and feather disease (PBFD) virus in psittacine birds, and porcine circovirus that causes post-weaning multisystemic wasting syndrome in pigs (Todd et al, 1991;Nayar et al, 1997). Circoviruses are tiny non-enveloped icosahedral viruses (15-24 nm in diameter) with a single-stranded circular DNA of 1.76 kb to 2.31 kb (Bassami et al, 1998;Niagro et al, 1998).…”