The canine parvovirus (CPV) infection is a highly contagious and serious enteric disease of dogs with high fatality rate. The present study was taken up to characterize the full-length viral polypeptide 2 (VP2) gene of CPV of Indian origin along with the commercially available vaccines. The faecal samples from parvovirus suspected dogs were collected from various states of India for screening by PCR assay and 66.29% of samples were found positive. Six CPV-2a, three CPV-2b, and one CPV-2c types were identified by sequence analysis. Several unique and existing mutations have been noticed in CPV types analyzed indicating emergence of newer variants of CPV in India. The phylogenetic analysis revealed that all the field CPV types were grouped in different subclades within two main clades, but away from the commercial vaccine strains. CPV-2b and CPV-2c types with unique mutations were found to be establishing in India apart from the prevailing CPV-2a type. Mutations and the positive selection of the mutants were found to be the major mechanism of emergence and evolution of parvovirus. Therefore, the incorporation of local strain in the vaccine formulation may be considered for effective control of CPV infections in India.

中文翻译：

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犬细小病毒的全长VP2基因分析表明在印度出现了新的变异体。

犬细小病毒（CPV）感染是具有高死亡率的高传染性和严重肠病犬。进行本研究以表征印度血源CPV的全长病毒多肽2（VP2）基因以及市售疫苗。从印度各州收集了细小病毒可疑狗的粪便样本，以进行PCR分析进行筛选，发现66.29％的样本呈阳性。通过序列分析鉴定出六种CPV-2a，三种CPV-2b和一种CPV-2c类型。在分析的CPV类型中已经注意到一些独特和现有的突变，表明在印度出现了CPV的新变种。系统发育分析表明，所有现场CPV类型都分为两个主要进化枝中的不同子进化枝，但远离商业疫苗株。除了流行的CPV-2a类型外，在印度也发现了具有独特突变的CPV-2b和CPV-2c类型。发现突变体和突变体的正选择是细小病毒出现和进化的主要机制。因此，可以考虑在疫苗制剂中掺入局部菌株以有效控制印度的CPV感染。