PDF(Pubmed)
Abstract：
Foot-and-mouth disease (FMD) outbreaks affecting Asiatic black bears (Ursus thibetanus) and a Malayan sun bear (Helarctos malayanus) were previously reported in 2011 in two housing facilities at a Vietnamese bear rescue centre. In this study, demographic data of all animals housed in the centre at the time of the outbreaks (n = 79) were collected. Blood samples drawn from 23 bears at different timepoints were tested for FMDV-specific antibodies targeting using a non-structural protein (NSP) ELISA and by virus neutralisation test (VNT). The relationship between seroconversion and clinical signs was explored and epidemic curves and transmission diagrams were generated for each outbreak, where FMD cases were defined as animals showing FMD clinical signs. Outbreak-specific attack rates were 18.75 and 77.77%, with corresponding basic reproduction numbers of 1.11 and 1.92, for the first and second outbreaks, respectively. Analyses of risk factors showed that after adjusting for sex there was strong evidence for a decrease in odds of showing clinical signs per year of age. All samples collected from bears before the outbreak tested negative to NSP and VNT. All cases tested positive to VNT following onset of clinical signs and remained positive during the rest of the follow up period, while only 6 out of 17 cases tested positive to NSP after developing clinical signs. Six animals without clinical signs were tested post outbreaks; five seroconverted using VNT and three animals were seropositive using NSP ELISA. This study provides initial epidemiological parameters of FMD in captive bears, showing that FMDV is easily spread between bears in close proximity and can cause clinical and subclinical disease, both of which appear to induce rapid and long-lasting immunity.
摘要：
先前于2011年在越南熊救援中心的两个住房设施中报道了影响亚洲黑熊（Ursusthibetanus）和马来亚太阳熊（Helarctosmalayanus）的口蹄疫（FMD）暴发。在这项研究中,收集爆发时在中心饲养的所有动物的人口统计学数据(n=79).使用非结构蛋白（NSP）ELISA和病毒中和测试（VNT）测试了在不同时间点从23只熊抽取的血液样品的FMDV特异性抗体靶向性。探讨了血清转换与临床体征的关系,并为每次爆发生成流行曲线和传播图,其中FMD病例定义为显示FMD临床体征的动物。特定于爆发的攻击率为18.75和77.77%，对于第一次和第二次爆发，相应的基本繁殖数为1.11和1.92，分别。对风险因素的分析表明，在调整性别后，有强有力的证据表明，每年出现临床症状的几率降低。爆发前从熊收集的所有样本对NSP和VNT均呈阴性。所有病例在临床症状出现后VNT检测呈阳性，在其余的随访期间保持阳性。而17例中只有6例在出现临床症状后检测出NSP阳性。爆发后测试了六只没有临床体征的动物；使用VNT将五只血清转化，使用NSPELISA将三只动物血清阳性。这项研究提供了圈养熊中口蹄疫的初始流行病学参数，表明口蹄疫病毒很容易在近处的熊之间传播，并可引起临床和亚临床疾病，两者似乎都能诱导快速和持久的免疫力。
