Sallu Raphael S, Kasanga Christopher J, Mathias Mkama, Yongolo Mmeta, Mpelumbe-Ngeleja Chanasa, Mulumba Misheck, Ranga Ezekia, Wambura Philemon, Rweyemamu Mark, Knowles Nick, King Donald
Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania and Southern African Centre for Infectious Diseases Surveillance, Sokoine University of Agriculture, Tanzania.
Onderstepoort J Vet Res. 2014 Apr 23;81(2):E1-6. doi: 10.4102/ojvr.v81i2.736.
Phylogeography data are of paramount importance in studying the molecular epidemiology dynamics of foot-and-mouth disease virus (FMDV). In this study, epithelial samples and oesophageal-pharyngeal fluids were collected from 361 convalescent animals (cattle and buffaloes) in the field throughout Tanzania between 2009 and 2013. The single plex real-time RT-PCR (qRT-PCR) assay for rapid and accurate diagnosis of FMDV employing the Callahan 3DF-2, 3DF-R primers and Callahan 3DP-1 probe were used. Preparation of the samples was performed according to the OIE manual, with a Kenya O serotype obtained from the attenuated vaccine serving as a positive control and samples collected from healthy animals serving as true negatives. The results indicated that 53.49% of samples (n = 176) were positive for FMDV genome by qRT-PCR, with Ct values ranging from 14 to 32. In addition, molecular typing of the FMDV genome positive samples using serotype specific primers revealed the existence of several serotypes: serotype South Africa Territory 1 (SAT1) (34.25%, n = 60), serotype A (68.92%, n = 98), serotype O (59.20%, n = 98) and SAT2 (54.54%, n = 96). The virus protein 1 sequences analysis for 35 samples was performed and the collective results indicated: 54.28% serotype O, 25.71% serotype A, 14.28% serotype SAT1 and 2.85% serotype SAT2. Therefore in this study, both the phylogenetic trees and spatial distribution of serotypes elucidated the phylodynamics of multiple FMDV field strains in Tanzania and neighbouring countries.
系统发育地理学数据在研究口蹄疫病毒（FMDV）的分子流行病学动态方面至关重要。在本研究中，于2009年至2013年期间从坦桑尼亚各地野外的361只康复动物（牛和水牛）中采集了上皮样本和食管-咽液。采用Callahan 3DF-2、3DF-R引物和Callahan 3DP-1探针的单重实时逆转录聚合酶链反应（qRT-PCR）检测法用于快速准确诊断FMDV。样本制备按照世界动物卫生组织手册进行，从减毒疫苗中获得的肯尼亚O血清型用作阳性对照，从健康动物采集的样本用作真阴性对照。结果表明，通过qRT-PCR检测，53.49%的样本（n = 176）FMDV基因组呈阳性，Ct值范围为14至32。此外，使用血清型特异性引物对FMDV基因组阳性样本进行分子分型，发现存在几种血清型：南非领土1型（SAT1）（34.25%，n = 60）、A型（68.92%，n = 98）、O型（59.20%，n = 98）和SAT2型（54.54%，n = 96）。对35个样本进行了病毒蛋白1序列分析，总体结果显示：O型占54.28%，A型占25.71%，SAT1型占14.28%，SAT2型占2.85%。因此，在本研究中，血清型的系统发育树和空间分布阐明了坦桑尼亚及周边国家多种FMDV野外毒株的系统发育动态。
