Namatovu Alice, Tjørnehøj Kirsten, Belsham Graham J, Dhikusooka Moses T, Wekesa Sabenzia N, Muwanika Vincent B, Siegismund Hans R, Ayebazibwe Chrisostom
National Animal Disease Diagnostics and Epidemiology Centre, Ministry of Agriculture Animal Industry and Fisheries, P. O. Box 513, Entebbe, Uganda; Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda.
National Veterinary Institute, Technical University of Denmark, Lindholm, DK-4771 Kalvehave, Denmark.
PLoS One. 2015 Feb 9;10(2):e0114811. doi: 10.1371/journal.pone.0114811. eCollection 2015.
To investigate the foot-and-mouth disease virus (FMDV) serotypes circulating in Uganda's cattle population, both serological and virological analyses of samples from outbreaks that occurred during 2012-2013 were performed. Altogether, 79 sera and 60 oropharyngeal fluid (OP)/tissue/oral swab samples were collected from herds with reported FMD outbreaks in seven different Ugandan districts. Overall, 61/79 (77%) of the cattle sera were positive for antibodies against FMDV by PrioCHECK FMDV NS ELISA and solid phase blocking ELISA detected titres ≥ 80 for serotypes O, SAT 1, SAT 2 and SAT 3 in 41, 45, 30 and 45 of these 61 seropositive samples, respectively. Virus neutralisation tests detected the highest levels of neutralising antibodies (titres ≥ 45) against serotype O in the herds from Kween and Rakai districts, against SAT 1 in the herd from Nwoya district and against SAT 2 in the herds from Kiruhura, Isingiro and Ntungamo districts. The isolation of a SAT 2 FMDV from Isingiro was consistent with the detection of high levels of neutralising antibodies against SAT 2; sequencing (for the VP1 coding region) indicated that this virus belonged to lineage I within this serotype, like the currently used vaccine strain. From the Wakiso district 11 tissue/swab samples were collected; serotype A FMDV, genotype Africa (G-I), was isolated from the epithelial samples. This study shows that within a period of less than one year, FMD outbreaks in Uganda were caused by four different serotypes namely O, A, SAT 1 and SAT 2. Therefore, to enhance the control of FMD in Uganda, there is need for efficient and timely determination of outbreak virus strains/serotypes and vaccine matching. The value of incorporating serotype A antigen into the imported vaccines along with the current serotype O, SAT 1 and SAT 2 strains should be considered.
为调查乌干达牛群中流行的口蹄疫病毒（FMDV）血清型，对2012 - 2013年期间发生疫情的样本进行了血清学和病毒学分析。总共从乌干达七个不同地区报告发生口蹄疫疫情的牛群中采集了79份血清以及60份口咽液（OP）/组织/口腔拭子样本。总体而言，通过PrioCHECK FMDV NS ELISA检测，79份牛血清中有61份（77%）针对FMDV的抗体呈阳性，在这61份血清阳性样本中，固相阻断ELISA分别在41份、45份、30份和45份样本中检测到血清型O、SAT 1、SAT 2和SAT 3的滴度≥80。病毒中和试验在来自Kween和Rakai地区的牛群中检测到针对血清型O的最高水平中和抗体（滴度≥45），在来自Nwoya地区的牛群中检测到针对SAT 1的最高水平中和抗体，在来自Kiruhura、Isingiro和Ntungamo地区的牛群中检测到针对SAT 2的最高水平中和抗体。从Isingiro分离出一株SAT 2 FMDV，这与检测到的针对SAT 2的高水平中和抗体一致；测序（针对VP1编码区）表明该病毒属于该血清型内的I系，与目前使用的疫苗株相同。从Wakiso地区采集了11份组织/拭子样本；从上皮样本中分离出了血清型A FMDV，非洲基因型（G - I）。本研究表明，在不到一年的时间内，乌干达的口蹄疫疫情由四种不同血清型即O、A、SAT 1和SAT 2引起。因此，为加强乌干达对口蹄疫的防控，需要高效、及时地确定疫情病毒株/血清型并进行疫苗匹配。应考虑将血清型A抗原与目前的血清型O、SAT 1和SAT 2毒株一起纳入进口疫苗。
