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.
History
Publication title
Journal of Animal Ecology
Volume
82
Pagination
182-190
ISSN
0021-8790
Department/School
School of Natural Sciences
Publisher
Blackwell Publishing Ltd
Place of publication
Oxford, UK
Rights statement
Copyright 2012 The Authors. Journal of Animal Ecology Copyright 2012 British Ecological Society
Repository Status
Restricted
Socio-economic Objectives
Assessment and management of Antarctic and Southern Ocean ecosystems