Rouby Sherin Reda, Bazid Abdel-Hamid, Wasfy Momtaz, El-Sayed Magdy
Department of Veterinary Medicine, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef 62511, Egypt.
Department of Virology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Menoufia 32897, Egypt.
Vet World. 2019 Dec;12(12):1924-1930. doi: 10.14202/vetworld.2019.1924-1930. Epub 2019 Dec 11.
Lumpy skin disease (LSD) and sheep pox are economically important -induced diseases of cattle and sheep, respectively. Despite the extensive vaccination program adopted by Egyptian veterinary authorities, LSD and sheep pox are still prevalent and spread throughout the whole country. The current study was designed for molecular characterization and phylogenetic analysis of LSD virus (LSDV) and (SPPV) recovered from field cases in Egypt along with vaccinal strains to assess their genetic relatedness.
Skin biopsies were collected from naturally infected cases of LSD in Ismailia (n=3 farms) and Beni-Suef (n=2 farms) Governorates and sheep pox in Beni-Suef (n=1 flock). Virus isolation was carried out on primary ovine fetal kidney and heart cell cultures. DNA was extracted from infected materials (skin lesions, infected cell cultures) as well as LSDV Neethling vaccine strain and Romanian SPPV vaccine strain. Polymerase chain reaction was performed using oligonucleotide primers targeting the entire open reading frame of G protein-coupled receptors (GPCR) gene and gene sequences were analyzed.
Virus isolation on primary ovine fetal kidney and heart cell culture revealed a cytopathic effect at the third passage characterized by rounding of infected cells and margination of nuclear chromatin. Comparative sequence analysis of GPCR gene revealed that Egyptian LSDV isolated from Ismailia and Beni-Suef shared 99:100% nucleotide and amino acid (AA) identities with each other. In comparison to the vaccinal strains, Egyptian LSDV isolates shared 98:99 nucleotide and AA identities with LSDV Neethling vaccine strain and 93:94% with SPPV Romanian vaccine strain. No differences at the nucleotide or AAs were observed between the SPPV vaccine and virulent strains (100% identity). Phylogenetic analyses revealed that LSDV Neethling vaccine strain is more related to field Egyptian LSDV and clustered within the LSDV group while Romanian SPPV vaccine strain clustered in a separate clade with SPPV field isolates.
Comparative sequencing and phylogenetic analyses of the GPCR gene reveal a minimal genetic variation between LSDV field isolates from different locations and a close relationship between virulent field strains and homologous vaccines.
结节性皮肤病（LSD）和绵羊痘分别是对牛和羊具有重要经济影响的诱发疾病。尽管埃及兽医当局实施了广泛的疫苗接种计划，但LSD和绵羊痘仍然流行并在全国范围内传播。本研究旨在对从埃及现场病例以及疫苗株中分离出的LSD病毒（LSDV）和绵羊痘病毒（SPPV）进行分子特征分析和系统发育分析，以评估它们的遗传相关性。
从伊斯梅利亚（n = 3个农场）和贝尼苏韦夫（n = 2个农场）省自然感染LSD的病例以及贝尼苏韦夫（n = 1群）的绵羊痘病例中采集皮肤活检样本。在原代绵羊胎儿肾和心脏细胞培养物上进行病毒分离。从感染材料（皮肤病变、感染的细胞培养物）以及LSDV尼斯林疫苗株和罗马尼亚SPPV疫苗株中提取DNA。使用靶向G蛋白偶联受体（GPCR）基因整个开放阅读框的寡核苷酸引物进行聚合酶链反应，并对基因序列进行分析。
在原代绵羊胎儿肾和心脏细胞培养物上进行病毒分离，在第三代传代时显示出细胞病变效应，其特征为感染细胞变圆和核染色质边缘化。GPCR基因的比较序列分析表明，从伊斯梅利亚和贝尼苏韦夫分离出的埃及LSDV彼此之间核苷酸和氨基酸（AA）同一性为99:100%。与疫苗株相比，埃及LSDV分离株与LSDV尼斯林疫苗株的核苷酸和AA同一性为分别为98:99，与罗马尼亚SPPV疫苗株的同一性为93:94%。在SPPV疫苗株和强毒株之间未观察到核苷酸或氨基酸差异（100%同一性）。系统发育分析表明，LSDV尼斯林疫苗株与埃及现场LSDV的关系更密切，聚集在LSDV组内，而罗马尼亚SPPV疫苗株与SPPV现场分离株聚集在一个单独的进化枝中。
GPCR基因的比较测序和系统发育分析表明，来自不同地点的LSDV现场分离株之间的遗传变异极小，强毒株与同源疫苗之间关系密切。
