Tesfaye Yeneneh, Khan Fazlurrahman, Gelaye Esayas
Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, Uttar Pradesh, India.
Department of Research and Development, National Veterinary Institute, P.O. Box: 19, Bishoftu, Ethiopia.
Vet World. 2020 Mar;13(3):542-548. doi: 10.14202/vetworld.2020.542-548. Epub 2020 Mar 24.
Foot-and-mouth disease (FMD) is endemic in several developing countries and affects poor farmers through loss of production, death of diseased animals, and loss of animal byproducts. Forty-three samples were collected from 12 sites of five geographical located areas from suspected FMD virus (FMDV)-infected cattle during 2018. This study aimed to isolate and characterize the FMDVs using reverse transcription-polymerase chain reaction (RT-PCR) and gene sequencing.
Forty-three FMDV-suspected clinical samples cultured on BHK-21 cell were examined, followed by virus serotype identification using RT-PCR and gene sequencing.
Twenty-nine (67.44%) samples were cultured on BHK-21 cell, of which 14 (32.56%) were not isolated; the 43 samples were analyzed using FMDV screening primers and serotype-specific primers. The contribution of the disease-causing serotype was serotype O of 8 (18.60%) samples, serotype A of 20 (46.51%) samples, and mixed infection (O and A) of 1 (2.33%) sample. Serotypes O and A were further characterized by phylogenetic analysis, which grouped them under East Africa 3 and Africa topotypes of genotype IV, respectively. Interestingly, serotype A was isolated for the 1 time from Keyet sub-woreda and Mulo woreda of Ethiopia, and mixed serotypes (O and A) were identified from the purchased animal.
Molecular test result, sequencing, and phylogenetic tree reconstruction analysis revealed that the 2018 FMD outbreak in Ethiopia was caused by FMDV serotypes O and A. FMDV serotype A was the predominant strain circulating in most study areas of the country. Infections in one sample with mixed serotypes of O and A were also reported. The authors recommend a vaccine matching study of those field isolated viruses with the vaccine strain.
口蹄疫（FMD）在多个发展中国家呈地方流行，通过生产损失、患病动物死亡以及动物副产品损失影响贫困农民。2018年期间，从五个地理位置区域的12个地点的疑似感染口蹄疫病毒（FMDV）的牛身上采集了43份样本。本研究旨在使用逆转录-聚合酶链反应（RT-PCR）和基因测序分离并鉴定FMDV。
对在BHK-21细胞上培养的43份疑似FMDV临床样本进行检测，随后使用RT-PCR和基因测序进行病毒血清型鉴定。
29份（67.44%）样本在BHK-21细胞上培养成功，其中14份（32.56%）未分离出病毒；使用FMDV筛查引物和血清型特异性引物对43份样本进行分析。致病血清型的构成情况为：8份（18.60%）样本为O型，20份（46.51%）样本为A型，1份（2.33%）样本为混合感染（O型和A型）。通过系统发育分析对O型和A型血清型进行进一步鉴定，结果分别将它们归类于基因型IV的东非3型和非洲拓扑型。有趣的是，A型血清型首次从埃塞俄比亚的凯耶特次县和穆洛县分离得到，混合血清型（O型和A型）则从购买的动物中鉴定出来。
分子检测结果、测序以及系统发育树重建分析表明，2018年埃塞俄比亚口蹄疫疫情由FMDV血清型O型和A型引起。FMDV血清型A是该国大多数研究地区流行的主要毒株。还报告了一份样本存在O型和A型混合血清型感染的情况。作者建议对那些现场分离的病毒与疫苗株进行疫苗匹配研究。
