Abstract：
Canine parvovirus type 2 (CPV-2) is a major cause of fatal gastroenteritis and myocarditis in puppies of domestic and wild carnivores. CPV-2 has accumulated changes over time lead to the emergence of three antigenic variants CPV-2a, CPV-2b, and CPV-2c. VP2 is the major capsid protein that determines virus antigenicity, and host range. Although the three CPV-2 variants were previously identified in Egypt, most reports covered a restricted geographic region and/or time period, and only analyzed partial fragments of VP2 gene. Therefore, this study was designed to test 100 rectal swabs collected from 7 Egyptian governorates between 2019 and 2021 for CPV-2 using PCR. A total of 65 positive samples were identified, mostly in pure dog breeds of young age. The three variants co-circulated in 2019, while CPV-2b was not detected in 2020 and 2021. The frequency of CPV-2b and CPV-2c was higher in 2019 and 2021, respectively. Analysis of CPV-2 full-length VP2 gene sequence from 19/65 positive samples has identified four common amino acid substitutions F267Y, S297A, A300G, Y324I, which are characteristic for the new CPV-2 variants currently circulating worldwide. Unique substitutions including A5G, G36R, V38E, Q370R, and G392V were recognized in certain samples, and appears to have distinct effect on receptor binding, nuclear translocation, and inter-species transmission. Phylogenetic analysis showed separation of CPV-2 strains into two clades. All strains of this study were classified in clade I with Asian strains. In conclusion, this study provides updated comprehensive molecular analysis of CPV-2 variants in Egypt.
摘要：
犬细小病毒2型（CPV-2）是家养和野生食肉动物幼犬致命性胃肠炎和心肌炎的主要原因。CPV-2随时间积累的变化导致出现三种抗原变体CPV-2a，CPV-2b,和CPV-2c。VP2是决定病毒抗原性的主要衣壳蛋白,和主机范围。尽管这三种CPV-2变种以前在埃及被发现，大多数报告涵盖了有限的地理区域和/或时间段，只分析了VP2基因的部分片段。因此,本研究旨在使用PCR对2019年至2021年间从7个埃及省收集的100份直肠拭子进行CPV-2检测.共鉴定出65个阳性样本,大多是年轻的纯狗品种。这三种变体在2019年共同传播，而在2020年和2021年未检测到CPV-2b。2019年和2021年CPV-2b和CPV-2c出现频率较高。对来自19/65阳性样品的CPV-2全长VP2基因序列的分析已经确定了四个常见的氨基酸取代F267Y，S297A,A300G,Y324I,这是目前在全球范围内流通的新CPV-2变体的特征。独特的替代品，包括A5G，G36R,V38E,Q370R,和G392V在某些样品中被识别，似乎对受体结合有明显的影响，核易位,和物种间传播。系统发育分析表明，CPV-2菌株分为两个进化枝。本研究的所有菌株均与亚洲菌株一起分类为I型进化枝。总之,本研究提供了埃及CPV-2变异体最新的全面分子分析.
