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Mink circovirus (MiCV), a virus that was newly discovered in 2013, has been associated with enteric disease. However, its etiological role in acute gastroenteritis is unclear, and its genetic characteristics are poorly described. In this study, the role of circoviruses (CVs) in mink acute gastroenteritis was investigated, and the MiCV genome was molecularly characterized through sequence analysis. Detection results demonstrated that MiCV was the only pathogen found in this infection. MiCVs and previously characterized CVs shared genome organizational features, including the presence of (i) a potential stem-loop/nonanucleotide motif that is considered to be the origin of virus DNA replication; (ii) two major inversely arranged open reading frames encoding putative replication-associated proteins (Rep) and a capsid protein; (iii) direct and inverse repeated sequences within the putative 5ʹ region; and (iv) motifs in Rep. Pairwise comparisons showed that the capsid proteins of MiCV shared the highest amino acid sequence identity with those of porcine CV (PCV) 2 (45.4%) and bat CV (BatCV) 1 (45.4%). The amino acid sequence identity levels of Rep shared by MiCV with BatCV 1 (79.7%) and dog CV (dogCV) (54.5%) were broadly similar to those with starling CV (51.1%) and PCVs (46.5%). Phylogenetic analysis indicated that MiCVs were more closely related to mammalian CVs, such as BatCV, PCV, and dogCV, than to other animal CVs. Among mammalian CVs, MiCV and BatCV 1 were the most closely related. This study could contribute to understanding the potential pathogenicity of MiCV and the evolutionary and pathogenic characteristics of mammalian CVs. [ABSTRACT FROM AUTHOR]

Background: Mink circovirus (MiCV) is a newly discovered pathogen associated with mink diarrhea. The prevalence and economic importance of this virus remain poorly understood, and no specific serological assay has been developed for the diagnosis of MiCV infection. Results: In this study, a recombinant capsid protein antigen expressed in Escherichia coli was utilized to establish an indirect enzyme-linked immunosorbent assay (iELISA). Results revealed that the assay had no cross-reactivity with other related pathogens, and the respective sensitivity and specificity of the proposed iELISA were 92.31% and 91.67% compared with those obtained of Western blot on 138 serum samples from minks. The correlation coefficient between iELISA and Western blot was 0.838 (p > 0.05). iELISA was applied to detect MiCV antibodies in 683 clinical serum samples from different farms from the major mink industry province in China, and 21 of 24 farms with 163 of 683 (23.87%) individuals were tested positive for MiCV antibodies. The positive rates of each of the 21 flocks ranged from 2.33% to 73.68%. Conclusions: These results indicated that iELISA was a sensitive and specific method suitable for the large-scale detection of MiCV infections in mink. This study provided an effective method for the serological diagnosis and positive rate investigation of MiCV infection. [ABSTRACT FROM AUTHOR]

Aleutian mink disease is caused by a highly contagious parvovirus (Aleutian mink disease virus, AMDV). This disease is one of the most commercially important infectious disease worldwide and causes considerable economic losses to mink farmers. The capsid protein VP2 is the major immunogenic antigenic protein of AMDV, and is involved in viral tropism, pathogenicity, and host selection. However, few reports have described the use of VP2-specific monoclonal antibodies (mAbs) in B-cell epitope identification and immunological detection. In this study, we produced a specific mAb, 1G5, against AMDV VP2 protein (amino acids: 200 ∼ 588) and characterized its specificity and relative affinity. Six partially overlapping truncated recombinant proteins and seven synthetized peptides were used to identify the epitopes recognized by 1G5. The results indicate that mAb 1G5 can distinguish AMDV, MEV and CPV2 with high affinity ( K a  = 5.37 × 10 9 ), and the minimal linear epitope is located in amino acid residues 459 EEEGWPAASGTHFED 473 . Sequence alignments demonstrated that the linear epitope was completely conserved among most Amdoparvoviruses except the bat parvovirus, where three substitutions ( 463 W- 463 F, 466 A- 466 G and 471 F- 471 Y) were noted. Our results reveal that the identified epitope might be a common B-cell epitope of AMDV antibodies, and the 1G5 mAb can be used to identify the cleavage of the capsid proteins during AMDV infection. This is also the first report of a B-cell epitope on AMDV capsid protein VP2 (VP2: 459–473) using a mAb. These findings have potential applications in the development of new diagnostic tools for AMDV. [ABSTRACT FROM AUTHOR]