Age-Structured and Vaccination Models of Devil Facial Tumor Disease

Tasmanian devil populations have been devastated by devil facial tumor disease (DFTD) since its first appearance in 1996. The average lifespan of a devil has decreased from six years to three years. We present an age-structured model to represent how the disease has affected the age and breeding structures of the population. We show that with the recent increase in the breeding of juvenile devils, the overall devil population will increase but not nearly to pre-DFTD levels. The basic reproductive number may be increased with the influx of young breeding devils. In addition, our model shows that the release of nearly 100 captive-bred, vaccinated devils into infected, wild populations may help eliminate the disease and hence enable the population\u27s recovery. Specifically, we demonstrate that with this release of captive-bred, vaccinated devils the basic reproductive number is decreased to below one