de Oliveira Pablo Sebastian Britto, Cargnelutti Juliana Felipetto, Masuda Eduardo Kenji, Weiblen Rudi, Flores Eduardo Furtado
Setor de Virologia, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria (UFSM), Av. Roraima, 1000, Prédio 63A, Santa Maria, RS, 97105-900, Brazil.
Programa de Pós-Graduação em Medicina Veterinária, Universidade Federal de Santa Maria (UFSM), Av. Roraima, 1000, Prédio 97, Santa Maria, RS, 97105-900, Brazil.
Arch Virol. 2019 May;164(5):1361-1369. doi: 10.1007/s00705-019-04198-w. Epub 2019 Mar 11.
Carnivore protoparvovirus 1 (canine parvovirus 2, CPV-2) has undergone a rapid evolution through mutations in the capsid protein VP2, giving rise to variants associated with unique clinicopathological and immunological features. VP2 is a major capsid protein involved in key steps of virus biology, including interactions with cellular receptors and with the immune system. This study analyzed the complete VP2 coding sequence of 38 CPV-2 isolates obtained from dogs with clinical parvovirosis in southern Brazil. Amplicons encompassing the whole VP2 coding region were subjected to nucleotide sequencing, and predicted amino acid sequences were analyzed to identify molecular markers of viral variants. Viral variants were classified as CPV-2a, -2b or -2c based on the presence of the amino acid Asn, Asp or Glu, respectively, at VP2 residue 426. Amino acid sequence analysis identified 20 CPV-2c and four CPV-2b isolates. Eleven viruses were identified as New CPV-2a, two as New CPV-2b, and one resembled the original CPV-2 and was designated CPV-2-like. In addition to the mutation at amino acid 426 of VP2, new 2a/2b variants containing a Ser297Ala mutation at residue 297 were identified. CPV-2-like samples contained some mutations that were also present in the original CPV-2 isolate, including as Leu, Thr, Ala and Asp at residues 87, 101, 300 and 305, respectively. The New CPV-2a isolates had three additional mutations (Phe267Tyr, Tyr324Ile and Thr440Ala) associated with selective pressure and development of disease in vaccinated dogs. The resemblance of the CPV-2-like isolate to CPV-2 suggests reemergence of CPV-2 and/or evolution from vaccine strains. Phylogenetic analysis grouped the variants with their respective reference strains, in general, according to amino acid changes. These results demonstrate the high VP2 diversity of CPV circulating in dogs in southern Brazil and indicate the emergence of new viral variants that differ markedly from the current vaccine strains.
肉食动物细小病毒1型（犬细小病毒2型，CPV - 2）通过衣壳蛋白VP2的突变经历了快速进化，产生了与独特临床病理和免疫学特征相关的变体。VP2是一种主要的衣壳蛋白，参与病毒生物学的关键步骤，包括与细胞受体和免疫系统的相互作用。本研究分析了从巴西南部患有临床细小病毒病的犬只中获得的38株CPV - 2分离株的完整VP2编码序列。对包含整个VP2编码区域的扩增子进行核苷酸测序，并分析预测的氨基酸序列以鉴定病毒变体的分子标记。根据VP2第426位残基处分别存在天冬酰胺、天冬氨酸或谷氨酸，将病毒变体分类为CPV - 2a、- 2b或- 2c。氨基酸序列分析鉴定出20株CPV - 2c和4株CPV - 2b分离株。11株病毒被鉴定为新型CPV - 2a，2株为新型CPV - 2b，1株与原始CPV - 2相似，被命名为CPV - 2样株。除了VP2第426位氨基酸的突变外，还鉴定出在第297位残基处含有Ser297Ala突变的新型2a/2b变体。CPV - 2样株样本含有一些也存在于原始CPV - 2分离株中的突变，分别为第87、101、300和305位残基处的亮氨酸、苏氨酸、丙氨酸和天冬氨酸。新型CPV - 2a分离株还有另外三个与疫苗接种犬的选择性压力和疾病发展相关的突变（Phe267Tyr、Tyr324Ile和Thr440Ala）。CPV - 2样株与CPV - 2的相似性表明CPV - 2的重新出现和/或从疫苗株进化而来。系统发育分析通常根据氨基酸变化将变体与其各自的参考菌株分组。这些结果表明巴西南部犬只中循环的CPV的VP2具有高度多样性，并表明出现了与当前疫苗株明显不同的新病毒变体。
