School of Zoology, University of Tasmania, Private Bag 5, Hobart, Tas., 7001, Australia.
J Anim Ecol. 2013 Jan;82(1):182-90. doi: 10.1111/j.1365-2656.2012.02025.x. Epub 2012 Sep 3.
The Tasmanian devil is threatened with extinction by devil facial tumour disease (DFTD), a unique infectious cancer in which the tumour cells themselves, which derive from a single long-dead host devil, are the infective agent and the tumour is an infectious parasitic cell line. Transmission is thought to occur via direct inoculation of tumour cells when susceptible and infected individuals bite each other or by fomitic transfer of tumour cells. The nature of transmission and the extent to which biting behaviour and devil ecology is associated with infection risk remains unclear. Until our recent study in north-west Tasmania showed reduced population and individual impacts, DFTD had caused massive population declines in all populations monitored. In this paper, we investigate seasonal patterns of injuries resulting from bites between individuals, DFTD infection status and tumour location in two populations to determine whether the number of bites predicts the acquisition of DFTD and to explore the possibility that the reduced impacts of DFTD in north-west Tasmania are attributed to reduced bite rates. Devils with fewer bites were more likely to develop DFTD and primary tumours occurred predominantly inside the oral cavity. These results are not consistent with transmission occurring from the biter to the bitten animal but suggest that dominant individuals delivering bites, possibly by biting the tumours of other devils, are at higher risk of acquiring infection than submissive individuals receiving bites. Bite rates, which were higher during autumn and winter, did not differ between sites, suggesting that the reduced population impacts in north-west Tasmania cannot be explained by lower bite rates. Our study emphasizes the importance of longitudinal studies of individually marked animals for understanding the ecology and transmission dynamics of infectious diseases and parasites in wild populations.
塔斯马尼亚恶魔受到恶魔面部肿瘤病（DFTD）的威胁，这是一种独特的传染性癌症，其中肿瘤细胞本身来自一个早已死亡的宿主恶魔，是感染剂，而肿瘤是一种传染性寄生细胞系。据认为，当易感和感染的个体相互咬伤时，肿瘤细胞会通过直接接种传播，或者通过肿瘤细胞的飞沫传播。传播的性质以及咬行为和恶魔生态学与感染风险的关联程度尚不清楚。直到我们最近在塔斯马尼亚西北部的研究表明，种群和个体数量减少，DFTD 已经导致所有监测的种群数量大幅下降。在本文中，我们调查了两个种群中个体之间咬伤导致的伤害的季节性模式、DFTD 感染状况和肿瘤位置，以确定咬伤次数是否可以预测 DFTD 的获得，并探讨在塔斯马尼亚西北部影响较小的可能性DFTD 归因于咬伤率降低。咬伤次数较少的恶魔更有可能患上 DFTD，原发性肿瘤主要发生在口腔内。这些结果与从攻击者到被攻击者的传播不一致，但表明施咬的主导个体（可能通过咬其他恶魔的肿瘤）比接受咬伤的顺从个体更容易获得感染。咬伤率在秋季和冬季较高，但两个地点之间没有差异，这表明塔斯马尼亚西北部的种群影响较小不能用较低的咬伤率来解释。我们的研究强调了对个体标记动物进行纵向研究的重要性，以了解野生动物种群中传染病和寄生虫的生态学和传播动态。
