Ludolphy Catharina, Kahle Patricia, Kierdorf Horst, Kierdorf Uwe
Department of Biology, University of Hildesheim, Universitätsplatz 1, 31141, Hildesheim, Germany.
BMC Vet Res. 2018 May 2;14(1):150. doi: 10.1186/s12917-018-1473-5.
Pathological changes and resulting functional impairment of the temporomandibular joint (TMJ) can substantially affect physical condition, morbidity, and mortality of wildlife species. Analysis of TMJ disorders is therefore of interest for the characterization of the health status of populations of wild mammals. This paper, for the first time, analyses the prevalence of TMJ osteoarthritis (TMJ-OA) and the spectrum of osteoarthritic bone lesions of the TMJ in the Eastern Atlantic harbour seal (Phoca vitulina vitulina), applying a standardized scoring system. Dry skulls of 1872 individuals from the German North Sea, collected between 1961 and 1994, were examined for lesions consistent with a diagnosis of TMJ-OA. Of the skulls, 913 (48.8%) were from male, 959 (51.2%) from female seals, with age at death ranging from 2 weeks to 25 years. Possible associations of TMJ-OA with dental or periodontal disorders were also analysed.
Lesions consistent with TMJ-OA were found in 963 (53.9%) of the 1787 juvenile/subadult (5 weeks to 5 years of age) and adult (> 5 years) specimens, the condition mostly (95.0% of affected individuals) occurring in a bilateral fashion. Males were affected more frequently than females (p < 0.001), while lesion severity tended to be higher in females (p < 0.05). Severity of TMJ-OA lesions was positively correlated with age (p < 0.001). Lesion severity was also weakly positively correlated with the number of fractured teeth (p < 0.05) and of intravitally lost teeth (p < 0.01), when controlling for age at death as a confounder.
TMJ-OA is a common disorder in the Eastern Atlantic harbour seal. The more pronounced severity of the lesions in females compared to males is basically attributed to the higher average age of the female subsample. The causes underlying the high prevalence of TMJ-OA in the studied assemblage remain unknown. Most of the specimens (75.3%) analysed in the present study were found dead during the first phocine distemper virus epizootic in 1988. Therefore, it is assumed that, contrary to other museum collections, only little overrepresentation of pathological skeletal conditions is present in this death sample compared with the population from which it originated.
颞下颌关节（TMJ）的病理变化及由此导致的功能障碍会严重影响野生动物的身体状况、发病率和死亡率。因此，分析颞下颌关节紊乱对于了解野生哺乳动物种群的健康状况具有重要意义。本文首次应用标准化评分系统，分析了东大西洋港海豹（Phoca vitulina vitulina）颞下颌关节骨关节炎（TMJ - OA）的患病率以及颞下颌关节骨关节炎性骨病变的范围。对1961年至1994年间从德国北海收集的1872个个体的干燥头骨进行检查，以确定是否存在与TMJ - OA诊断相符的病变。这些头骨中，913个（48.8%）来自雄性海豹，959个（51.2%）来自雌性海豹，死亡年龄范围从2周龄至25岁。还分析了TMJ - OA与牙齿或牙周疾病之间可能存在的关联。
在1787个幼年/亚成年（5周龄至5岁）和成年（>5岁）标本中，有963个（53.9%）发现存在与TMJ - OA相符的病变，这种情况大多（95.0%的受影响个体）以双侧形式出现。雄性比雌性更易受影响（p<0.001），而雌性的病变严重程度往往更高（p<0.05）。TMJ - OA病变的严重程度与年龄呈正相关（p<0.001）。在将死亡年龄作为混杂因素进行控制后，病变严重程度与折断牙数量（p<0.05）和生前脱落牙数量（p<0.01）也呈弱正相关。
TMJ - OA在东大西洋港海豹中是一种常见疾病。与雄性相比，雌性病变严重程度更明显，这主要归因于雌性子样本的平均年龄较高。在本研究群体中TMJ - OA高患病率的潜在原因尚不清楚。本研究分析的大多数标本（75.3%）是在1988年首次发生的海豹瘟热病毒疫情期间被发现死亡的。因此，与其他博物馆收藏的标本相反，据推测，与该死亡样本所源自的种群相比，该死亡样本中病理性骨骼状况的过度代表性较小。
